This section is devoted to the information that will be useful in the creation of a Kin's Domains.
The Incredible Benefits Of Speed Reading
Speed reading involves not only the ability to read vast amounts of information at an accelerated rate but also the ability to absorb and comprehend the information you've just read. This can be a huge benefit during school and in many professions that require copious amounts of reading on a daily basis.
In addition to reading and retaining more information more rapidly speed reading has other benefits as well. Among these benefits are not needing to go back and reread passages that have already been read as frequently (this process is known as skip back), lessening the amount of time in which your eyes linger on particular words or blocks of words, and enlarging the area upon which your eyes rest while reading. This is known as the fixation zone and includes the word or block of words that you are reading at any given time. Some people can only manage a word or two at a time and others can read entire lines at a time. The more words you can read at a time, the faster you will ultimately read.
While it probably comes as little or no surprise that speed reading gives most students a noticeable edge in the studies, it may come as a surprise to discover that students who can speed read in another language (their native language) have a much easier time of learning English as a second language than those who have not developed this particular skill. They are much more likely to excel in the learning of a new language and far less likely to give up the learning of a new language.
There are also many professions that will find speed reading abilities of an incredible benefit as well. The very first one that comes to mind is the field of law. Attorneys and judges must perform massive amounts of reading in the course of an ordinary day, the faster they can read and comprehend the material at hand the quicker they can manage decisive action in regards to the materials they've just read.
Scholars and professors must also do a great amount of reading as do journalists, reporters, writers, novelists, researchers, and any number of other professions. We live in a world that is moving at the speed of sound many days in order to keep up with the world it is becoming more and more necessary to develop speed reading skills rather than the hobby or edge that it once may have been within professional communities.
Even recreational reading benefits from speed reading. The less time you spend the reading, the less eye strain and fatigue you are likely to experience. Additionally, eliminating the need to linger as often is a great benefit to your reading times and how quickly you can go through a book that might have you on the edge of your seat. While speed reading is murder on your book budget, it is a great way to work in a great novel over the course of a night or a weekend.
For those who love and live to read, speed reading is the only way to go. As your skills improve so does you ability to not only learn new things rapidly but also retain the knowledge you've gained. For many, that alone is worth the price of a speed reading course or two.
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Teach speed reading to your children even if you can't speed read yourself
By George Stancliffe
For over two years, I have had the hobby of teaching speed reading to people in the community where I live. So far I have taught over 300 people (most of them children) to speed read.
As a result of the many classes I've taught, I've made some observations:
- Children learn the speed reading skill far more easily than adults.
- Children master the skill far more completely than adults do. It literally becomes a natural part of them if they learn it by age 12 or so, just as much as speaking.
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English is a natural part of them.
In fact, recently I made the discovery that children learn to speed read so easily that you can teach kids to speed read even if you don't know how to speed read yourself.
Impossible? Not at all. I even tested the idea out on some school teachers and homeschoolers who gave it the acid test. They did just fine.
One homeschooling mother got her 11-year-old daughter to read comfortably at 12,000 words per minute (most adults read at about 250 to 300 wpm). An English teacher at a local high school got two thirds of her class to catch on to speed reading within four weeks at an average speed of about 4,000 wpm. Others who gave this concept the acid test had similar results.
Let me repeat: The instructors did not know how to speed read themselves.
So why can't I just learn speed reading first, before teaching it to my kids? You can, but in my experience as an instructor, it isn't going to happen. It's at least 10 times harder for an adult to learn speed reading than it is for a child. By the time you finish struggling through the process yourself you will be so weary that you'll doubt that children are capable of learning it at all. Teaching it is really the easy part.
I've checked out a number of commercially available speed reading courses and they usually don't even allow kids under 11- to 13-years of age to enroll. That's too bad. Ninety percent of my very best students were 12 and under. Most of the rest were aged 13 to 14. Older kids can get good at speed reading but they have to work harder at it. The professionals are locking out most of their star students and only admitting their worst prospects. I believe they don't promote their speed reading courses to kids for three reasons:
- Money. The adults have it, the kids don't.
- The methods they use to teach speed reading are so rigorous that no young children could survive them. I took one speed reading course that required one hour of homework each night, much of it in the form of written notes or "recall patterns." No kids will ever keep up with that amount of paperwork.
- It probably has never occurred to them that children could master the speed reading skill very easily, as long as it's presented to them in the right way.
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The following method for teaching kids to speed read may not be the only way to teach them. It may not even be the best. But I haven't come across any other that is so simple. And no other method I am aware of allows a non-speed reader to teach it effectively.
This article is an abbreviated plan for teaching your kids to speed read.
Keys to speed reading
There are four major keys to learning to speed read:
- Natural vision
- Visualize
- Relax
- Daily practice
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Let me briefly explain each one.
Natural vision: Take a minute right now and look at a picture. Let's just say that you're looking at the Mona Lisa. When you look at her does your vision narrow down to tunnel vision so that you see just her left eye? Of course not. Yet when we look at a page of print we have been trained to have tunnel vision. You may as well read through a straw.
You need to look at a page of print with the same natural vision that we use to see a whole picture at once. With natural vision you use your whole field of vision (peripheral vision) to catch large blocks of print on a page. You not only see 3 to 10 words per line, but you also see 3 to 10 lines of print at once also.
Using your natural vision to see the words is the chief cornerstone of speed reading.
There are many different ways of seeing all the words on a page using your natural vision. By experimenting you will find the method that works best for you. (Figure 1.)
Visualize: Have you ever read a really good book, one that was so good that you felt that you were living inside the story, or you were able to picture it in your mind so well that it was like watching a good movie? Well, that is your goal when you visualize.
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Figure 1. There are different ways of seeing all the words on a page using natural vision. By experimenting you will find the method that works best for you.
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The trouble is that your mind has never visualized like this while reading before, so it will take effort to jump-start the visualization process. In fact, for the first day or so, it may seem impossible. But keep trying anyway.
Relax: Normally, when people concentrate on something they focus their minds on something and become somewhat mentally tense. With speed reading it is different. To get maximum comprehension, one must be relaxed while concentrating (visualizing). One can get a feel for this relaxed feeling after doing the casual reading exercise that I explain later. Once you get a feel for how to properly relax while visualizing, it will become easier to become relaxed whenever you speed read.
Daily practice: The importance of daily practice cannot be overstated. After teaching many speed reading classes, one trend has become obvious: Those who practice daily are the ones who get really good at speed reading while those who neglect it don't get good at it.
Of course, all is not lost if you forget to practice once or twice each week. But the more you skip practice, the worse your end result will be. This is especially true for adults. Sometimes I get kids who forget to practice regularly who still catch on to speed reading. However, they don't get as good as the kids who are diligent in their practice. I recommend at least 15 minutes of relaxed, casual speed reading each day. This is in addition to the regular lessons.
Preparation & equipment
Before we start, here's the preparation we need to make:
- Mark out on the calendar one month that you will stick to the program of at least two speed reading lessons per week. Of course, the more lessons you have per week, the better your results tend to be. This is because even when the kids forget to practice on their own, they will still get some daily practice for that day during the lesson.
When I teach a speed reading class twice a week, I make the lessons 90 minutes long. However, when I teach daily classes, 25 to 30 minutes is sufficient, as long as you make good use of your time. One homeschool parent I know found it more effective to break practice sessions up into 15 minute blocks, twice per day. Her daughter got to where she could cruise at over 10,000 words per minute with good recall.
- Collect enough interesting reading materials. Anything that is easy to read and interesting is appropriate: Goosebumps, Hardy Boys, Babysitter's Club, etc.
But please note: a few kids have difficulty catching on to speed reading using books containing regular-sized print. So what I usually do is start all of them off, for the first day or two at least, with something that has very large print. If they are 10-years-old or older, the large-print edition of Reader's Digest magazine is good. If that is too technical for them, then the Little Sisters series by Ann M. Martin has the largest-sized print that I've seen for regular reading books for kids. Try that. After a few days, at most, they should ease their way into normal-sized print.
All these materials should be easily available at your local library. Yard sales and Goodwill are another possible source.
- You'll need a watch with a second hand for timing regular drills and tap drills.
- You may need to make arrangements with other homeschoolers to get enough kids together to do a class.
It has been my experience that kids learn to speed read better in a group setting than they do in a tutoring environment because in any group of 6-10 kids, there is almost always at least one kid who will catch on to the skill immediately, usually within three days or so and sometimes on the very first day. The others will try hard, but may not get it for a couple of days more. If there isn't someone in the group who catches on to speed reading really soon, it is easy for most kids to give up on speed reading after the first week. Outwardly they may go through the motions, but secretly they are saying, "This is baloney, nobody can read this fast."
To keep the kids (and adults) motivated, it is important to insure that there is at least one kid in the class that will be the catalyst that will help motivate the others. Once they see others speed reading in real life, or even doing it themselves, it is much easier for them to "remember" to practice every day on their own.
- Also plan to have a minimum of two months follow-up after the initial month of instruction. This consists of getting them into the habit of always speed reading 10-15 minutes per day on a continuing basis. This is not only easy to do, but it's necessary. This 10-15 minutes should be spent speed reading books that are enjoyable to the child. No pressure. Just, "Here, read this book and tell me about it." That's it for the day. Most kids can speed read a fun book in 10 minutes or so.
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Now that you have made the preparations for teaching the course, it is time to discuss the basic activities that take place during class time. After that I will present a simple lesson plan that will help you to quickly see how a block of class time should proceed.
Basic class activities
Drills: A drill is a timed period (usually 30 seconds long) in which the student speed reads as many pages as he can. Afterwards, he reports on what he recalls to the instructor or to a class partner.
Speed reading drills help to build speed. They are short enough to enable the student to recall at least some of what he reads, yet long enough to make a significant dent in a reading selection. I encourage students to see at least six pages during a drill. It's common for 10-year-olds to be two or three times faster than this.
While doing drills, the focus is on visualization. Of course, we attempt to recall what we can immediately after each drill. But good recall may not always be attained. Sometimes there may not be any recall at all. This is okay. Just the effort to visualize, alone, is the main point of the drill.
After a couple of weeks, fair comprehension (35% to 65%) is commonly attained in drills. I come at the comprehension figure by just asking the student, "About how much of the material are you understanding?" The students actually have a pretty good idea of how much they've learned.
Reading speed during drills is different for each student. Some kids only see 6 pages, while others can read 15 to 20 pages, or more, with good comprehension during one drill.
Drill sets: In this course, speed reading drills are arranged into sets of three drills each. This is for the purpose of building greater speed and comprehension than would be achieved by reading each selection only once.
Commonly, on the first drill, a student will read only a few (example: five or six) pages in 30 seconds, and his comprehension will be not-so-good. I'll count any comprehension, even if he understood it only as he was reading through the selection but forgot it immediately.
However, the second time through the same story, he will often go faster, like seven or eight pages, and he will comprehend it better at the same time.
Then, finally, on the 3rd drill, the student will often be capable of even better speed and comprehension.
Tap drills: Tap drills are absolutely essential to building and maintaining high reading speeds with good comprehension. Here's an example of how I do them: Give the students three seconds to complete each page. Tap your pen on the table every three seconds for about three minutes. Then give them another three-minute tap drill at two seconds per page. Finish off with a one second tap drill for three more minutes. I usually do two or three tap drills per day just after a series of drill sets, but they can be useful any time the kids are starting to slow down too much.
Casual reading: Usually, at the end of each lesson I have 5 to 10 minutes of what I call "Casual Speed Reading" or just Casual Reading. The goal is to learn to relax while concentrating and visualizing. Go through the book at a comfortable rate, usually about three to five seconds per page—faster if you wish. Just make sure it is an even methodical pace. Don't worry if you have already read part of the book before while you are going through. Keep alert, deep seeing large groups of words with your peripheral vision. Keep trying to Visualize and Relax at the same time.
While students are doing the casual speed reading, discreetly time how many seconds per page they are reading. This way you can calculate an approximate reading speed for them. Many children's books have around 200 words per page, so six seconds per page would be 2,000 wpm; 4 seconds per page, 3,000 wpm; 2 seconds, 6,000 wpm; and 1 second, 12,000 wpm.
During the casual speed reading, quietly announce to each student what his reading speed is so that each will know his progress. I also ask them how much they are understanding. Often it is quite a bit. I have found that this alone motivates kids more than almost anything else. They had no idea that they could read 3,000 wpm or better. That's 10 times faster than most college graduates.
Occasionally, someone will get bogged down in an interesting story and revert to the old way of reading. When this happens, just encourage him to speed up next time.
Fun rewards: Bored children will not practice on their own, no matter how much you nag. Uninterested kids will not even believe that speed reading is possible. I vividly recall one class of third and fourth graders I taught. On the second day of class I nonchalantly asked them which ones had practiced for at least 15 minutes the previous night. Only three children raised their hands. I then pulled three packs of Grandma's Cookies out of a hiding place, tossed them to the diligent ones for a reward, and announced to the others, "Gee, that's too bad nobody else remembered to practice."
A few happy kids ate cookies in front of their friends that day. That's bad manners, but it's good motivation. Nobody forgot their homework again. I reward the kids for their efforts every day. I also reward them for achieving their goals in any activity that I can think of to keep the excitement up. I rarely forget to bring something for those who make the effort. It makes a big difference.
Lesson plans
For these lessons I am assuming a 45 minute block of time is available each day for five days per week. This course will last for four weeks.
Lesson 1:
The lesson plan for Lesson 1 is different from the rest of the lessons. That is because this is where the children are introduced to all of`the basic concepts and activities of speed reading. After Lesson 1, the rest of the lessons are pretty similar, the main differences only being the alterations you make to tailor the course to fit your needs. Conduct Lesson 1 as follows:
1. Pre-test the students to tabulate current reading speed.
2. Explain natural nision. Give the kids five seconds to see all the words on one page using Natural Vision as you've explained it. Tell them, "Do not try to understand anything. If you understand anything you are going too slow." Repeat this step, if necessary until all the kids understand the concept of Natural Vision.
3. 30 Seconds: See all the words clearly, on as many pages as you can. Do not try to understand anything. This is only for the purpose of getting used to using your Natural Vision. If the kids aren't seeing at least six pages of print clearly, repeat this step so they learn to go fast.
4. 30 Seconds: Going at least as fast as you did in step 3, try to understand one word per page. Do not slow down for this. Don't stop so that you can better focus in on any particular word. Only use your Natural Vision. Report how many pages you covered.
Usually, if you concentrate, a random word will jump out at you from somewhere on the page. Don't slow down to think about it when it jumps out at you. Just keep going fast. Also, this word will vanish from your mind just as fast as it came. Don't worry about that. It still counts. Recall will come later with time and practice.
5. 30 Seconds: Understand 3 words per page, otherwise same rules as for step 4.
Report how many pages you covered.
6. 30 Seconds: Understand five words per page. Same rules as step 5.
7. 30 Seconds: Understand seven words per page. Same rules as step 5.
8. By now they should be used to using their Natural Vision. We will now work on Visualization.
30 Seconds: See as many pages as you can, and try to get a general understanding of what the story is about. Do not slow down. At least, try not to slow down. Try to Visualize as much as possible. Don't worry if you forget everything immediately after the drill, this is a common occurrence at this point. Just do your best.
9. 30 Seconds: Do the same reading selection again that you did in step 8. Tell the instructor all about it, especially anything new that you didn't catch the last time.
10. 30 Seconds; Same as step 9.
11. Tap drill. Three seconds between each tap for 2 minutes. If anybody finishes their book during the tap drill, they can either start the book over again or pick up another book quickly and keep on going.
Remind the kids during the tap drill to focus their energies on trying to visualize and relax at the same time. Even if they feel like they are getting nothing out of it, they are to at least see all the words on each page with their Natural Vision and try to Visualize and Relax.
12. Two-Second Tap Drill. Same as step 11, but two seconds between each tap.
13. One-Second Tap Drill. Same as step 11, but only one second between each tap.
14. Casual Reading. They should speed read fast enough to challenge themselves, but slow enough to get some enjoyment value out of it.
Try not to go slower than five seconds per page. If only one kid is going too slow, overlook it. But if much of the class is starting to slow way down, start tapping your pen at five seconds per tap and tell them they have to go as fast as the taps or faster.
During the Casual Reading let each child know approximately how fast he is reading.
15. Assign the kids to practice on their own with Casual Reading for 15 minutes tonight.
Lessons 2 to 20:
1. Reward those who practiced for at least 15 minutes last night.
2. Do a Drill Set (three drills) at 30 seconds per drill in the same story or selection. Divide the class into groups of two or three students per group. Have each student tell all their recollections to their partner. Have them be sure to always use Natural Vision and try to Visualize in all their speed reading from now on.
3. New story or section. Repeat step 2.
4. New story or section. Repeat step 2 again.
5. Three-Second Tap Drill for three minutes. Remind the kids to Visualize and Relax during each Tap Drill.
6. Two-Second Tap Drill for three minutes.
7. One-Second Tap Drill for three minutes.
8. Casual Reading. Have them go fast enough to be challenged, yet slow enough to get some enjoyment out of it.
As the kids are speed reading, go to each one and tell him or her how fast he or she is reading.
If any of the children are still using very large print materials, try to wean them off them and onto more normal-sized print by Lesson 5.
On Tap Drills, kids are always allowed to go faster than the taps if they wish, but not slower.
After Lesson 10 you may want to spend more time on three to five minute Casual Readings, followed by telling your partner all about it, and less time doing the drill sets.
After Lesson 10 you may want to skip the three-second Tap Drill.
Throughout the course, remind the students that they should practice for 15 minutes each day, after the four-week course ends, for the following two months. More would be better. If practicable, make a poster and put it on the wall to remind everyone. Or send a note home to parents to make sure it gets done.
Comprehension
So that you won't get discouraged in the middle of the course, you need to know what to expect. The only kind of comprehension I look for is what I sometimes call "passing through" comprehension. That is, those things that you understand while you are just passing through the reading material. If you understand 70% of the material while you are reading, but one second after finishing you can only remember 20%, I still stand by the 70%.
Why? Because the only difference between the two is time and regular use of the skill. The part of your brain you use for speed reading has never been used before. And just like a broken leg that has been in a cast for six months and can't yet support you. This part of your brain has no strength to hang on to any comprehension at first. But if you exercise your brain regularly by using your speed reading talent, your ability to recall what you recognize while passing through will increase dramatically.
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Figure 2. This chart shows how the students' comprehension develops slowly at first, then improves at an accelerated pace before tapering off as it nears 100%.
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So the real goal to shoot for is the passing-through comprehension. The long-term recall will just take care of itself with time and regular use.
There is another matter which concerns some kids with regard to comprehension. Some people who don't catch on to speed reading as quickly as others get frustrated because their comprehension isn't increasing as quickly as others in the same class.
I diffuse this frustration by explaining that everybody learns this at a different rate and it has nothing to do with IQ. I draw my Comprehension Chart (Figure 2) and explain the Three Stages of Comprehension that we all go through while learning to speed read:
Stage 1: The Beginner's Stage. This is the first part of the course when we are seeing many words and understanding almost nothing. Some children pass out of this stage on day one. Some adults stay here for three weeks. Most children that I teach stay here for about a week. However, if you are teaching a very small class chances are you may not have that one student who catches on and leads the way and your students may remain at this stage longer than average.
Stage 2: This is the Growth Stage. Your mind is finally able to begin grasping the skill and making sense of the material at high speeds. Comprehension may increase steadily over two weeks time to 60% to 80%. Or it may shoot up to 70% to 90% in just a day or two for some kids.
Stage 3: This is the Power Stage. This is where speed reading begins to be a powerful tool for learning. Comprehension almost levels off, usually at around 60% to 80%. Some kids reach this stage within two days. Others need a few weeks. After this, the comprehension slowly increases just a little bit more each week as it gets closer and closer to 100%. Day by day a student won't notice any improved comprehension. But week by week, or even month by month, the differences will be noticed.
The Power Stage is also the time when the brain bridges the "recall gap," where the long-term recall begins to catch up with the "passing-through" comprehension. As always, this happens much more quickly for children than for adults.
Questions and answers
Q. If I learn to speed read, will I still be able to read the old way whenever I need to?
A. Yes. They are two different skills. You'll find that you will prefer to use speed reading for some jobs and regular reading for others.
Q. I want to learn speed reading too. Should I try to teach myself to speed read while I am teaching the kids?
A. I don't recommend it. It usually messes up the system. If you want to teach yourself to speed read, I recommend you teach the kids first and yourself later, or have one of the kids help you through it.
Q. Is it true that some kids develop photographic memories as a result of mastering the skill of speed reading by the age of 10?
A. In some cases, I believe this to be true. However, more research needs to be done in this area.
Q. How young can kids be taught to speed read?
A. I teach anybody that is reading competently on the 3rd grade level or better, regardless of age.
Q. What about those video or audio courses?
A. I'm sure those courses are good, but they are geared for adults, not kids. Even so, I've never encountered anybody who mastered speed reading from a video course, have you? I believe the reason that in-class courses with real, live teachers are more successful is because in a live class everybody is accountable to a teacher for completing each assignment. However, in video courses, there is no accountability.
Finally, not too long ago, while I was at the library making some copies, a 10-year-old girl came in. I saw her go up to the checkout desk with a stack of five books. I recognized her as Shawna, who had been in one of my speed reading classes over a year ago. I asked her if she still speed reads and she said she does. Of course, I expected this from looking at the five books she had. Her mother was standing nearby and said that Shawna reads books really fast. Meanwhile, Shawna went back to fetch more books from the shelves.
Moments like this make me glad that I teach speed reading.
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Speed Reading for Kids
The Pros and Cons of a Low Fat Diet
by Joan Salge Blake, MS, RD, LDN.
Blake is a nutrition professor at Boston University and a nationally known writer, lecturer and nutrition expert.
The Pros
One of the major benefits of a low fat diet is the potential for cutting back on calories in an attempt to better manage your weight. Since fat serves up more than double the amount of calories per gram (9 calories per gram) as compared to carbohydrates and protein (4 calories per gram each), cutting back on fat, theoretically, will provide you with more caloric trimming for your efforts. For example, dousing your dinner salad with two tablespoons of an oily Italian salad dressing will glisten your greens with approximately 140 extra calories while the same amount of a low fat Italian salad dressing will cover your salad for a mere 32 calories, a trimming of over 100 calories. With over 5,000 low fat food products available, fat-conscious consumers have a plethora of leaner options available in supermarkets that will meet their needs and satisfy their palates.
Since the Nutrition Fact Panel on the back of the food product label must list the grams of fat in a serving of food, it is relatively easy to keep track of your fat intake. (See the food label panel below.) The front of the food label can also help you when you are low fat shopping. By law, a food product that is labeled as "low fat" must contain 3 grams or less of fat per serving, whereas a "fat-free" food must contain less than 0.5 grams of fat in a serving.
Low fat diets could also help lower your risk of heart disease. Since the total amount of fat that you eat is a combination of both artery-clogging saturated fat and heart-healthy unsaturated fat, reducing the amount of fat in your diet to between 20 to no more than 35 percent of your calories will help you harness your saturated fat intake. A high amount of saturated fat in your diet can raise your "bad" LDL cholesterol levels in your blood. Too much of the "bad" LDL cholesterol in your blood can increase your risk for heart disease. In fact, if more than 35 percent of your daily calories are coming from fat in your diet, it would become extremely challenging to keep your saturated fat intake to a modest amount.
The Cons of a Low Fat Diet
Many individuals mistakenly think that a diet chock full of low fat foods is automatically a low calorie, healthy diet. It isn?t. Jelly beans, soda, fat free ice cream, cookies and pretzels are all low in fat but they aren't low in calories, especially if you eat them without regard to portion sizes. In fact, a diet that is full of low fat treats can quickly add up to a high calorie, unhealthy diet. It isn't a coincidence that the weight of Americans has been steadily climbing over the last couple of decades, and they have also been simultaneously tacking on approximately an extra 300 calories daily, on average.
Interestingly, the majority of these extra calories are coming from sugars and refined grains (products made with white flour), which are both low in fat. Any excess calories in your diet, whether they are from full fat or low fat foods, can contribute to weight gain.
Reducing fat too dramatically in the diet can also be unhealthy for certain individuals. For some sedentary, overweight individuals, a diet that is low in fat and high in carbohydrates can cause an increase of triglycerides (fat) in the blood, a decrease of the "good" HDL cholesterol, and an adverse change in the size of the "bad" LDL cholesterol. All of these changes add up to an unhealthy combination for your heart. (A high amount of the "good" HDL cholesterol is protective against heart disease.)
Also, a diet too low in fat can also cause you to come up short with some important dietary nutrients, such as the mineral zinc, some B vitamins, and certain essential fatty acids that your body needs. (A fat is made up of fatty acids.) You also need some fat in your diet in order to help your body absorb the fat-soluble vitamins A, D, E, and K, as well some compounds such as lycopene. Lycopene is found abundantly in tomatoes and tomato products and may be protective against prostate cancer.
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Why Fat-Free Foods Are Not As Good For You As You Might Think
We try so hard to make wise choices with our food. We select fat-free, light or diet versions of various foods in hopes of cutting calories and losing, or at least not gaining, weight. Is this a good solution? You may be surprised to hear this, but NO! Fat-free foods are actually more harmful for your overall health than the full fat versions. Here is some proof.
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The more educated you are about the hidden dangers of certain foods, the easier it is to make a decision what to fuel your body with. Photo: web
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According to USDA and FDA labeling laws, foods labeled fat-free do NOT have to be fat-free. They just have to have less than 0.5 grams of fat per serving. Low-fat foods must have 3 grams or less per serving. Reduced fat must have 25% less fat than the full fat versions, and Light must have 1/3 less calories or 50% less fat than the full fat version. So now you can see how the labels can be misleading. Also, many times people tend to eat MORE of the food because of the label, and may end up inadvertently eating more calories and fat than they would have with a standard serving of the original.
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Reading labels is a good habit, but it can be misleading. The rule of thumb is, the less ingredients, the better it is for you. Photo: web
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Next time you are at the store, compare the labels of a full fat and a fat free counterpart of any given food. We will use Daisy brand sour cream as an example. Original Daisy Sour Cream has only one ingredient: Grade A Cultured Cream. In comparison, the Fat-Free Daisy Sour Cream contains Cultured Skim Milk, Modified Food Starch, Carrageenan, Vitamin A Palmitate. What are the added ingredients? Modified food starch is a starch that has been changed through chemical, enzymatic or physical ways to enhance some quality of the starch (ie gelling, thickening, stabilization). Carrageenan is an extract from seaweed used as a thickening agent. Vitamin A Palmitate is found in fish and fish liver oil, but is most commonly made synthetically by chemically altering Vitamin A (which is very unstable on its own). Why do we need all these extra ingredients when the original version is only made of CREAM? We know what cream is, where it comes from and how to pronounce it, but how about the other three?
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"Light" of fat-free is not necessarily good. Photo: web
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Basically, to make foods fat free, light, etc. the manufacturers take out NATURAL ingredients that contain the fat and calories, and replace them will modified or chemical ingredients in an attempt to achieve a flavor that resembles the original version. Do you agree that if something is NATURAL, it has to be better for us than a chemical? Your body knows what to do with the natural ingredients; it was made to process them. When you eat synthetic foods your body doesn't know what they are or what to do with them, so it has adverse and sometimes toxic reactions to them like creating free radicals that damage healthy cells or are being broken down and stored as fats.
Think twice next time before you reach for the fat-free version of a product you like. Is it really better for you, or does it just create the opposite effect?
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Truth about Fat, Trans Fat, Saturated Fat and Nutrition
Should You Get the Flu Shot?
By Natasha Turner, ND
It's flu season again, and in light of the recent SARS outbreak, health departments, government agencies, school boards, as well as corporations are pushing everyone to take the flu shot this year. Before you opt for the flu shot, be sure you are making an informed decision by considering some of the pros and cons associated with flu vaccination.
What is the Flu?
Symptoms of influenza include fever, chills, muscle aches, headache and/or cough. In most cases, the illness lasts three to seven days, but some people have more severe cases or complications that require hospitalization. About 20,000 people in the U.S. die each year as a result of the flu or flu complications. Most of those who die are elderly, young children or people with compromised immune systems.
The flu is different from a cold:
Pros of the Flu Shot
Flu shots can decrease the risk of upper respiratory illness by 25%.
Flu shots can reduce work absenteeism due to illness by 36%.
Flu shots can reduce doctor visits for upper respiratory illness by 44%.
In addition to helping elderly people avoid an unpleasant and possibly dangerous illness, a flu shot can provide some protection against hospitalization for heart disease and stroke.
Immunizing high-risk people prevents many potential deaths from influenza. Immunization of those who care for high-risk people decreases the potential of spreading the flu from otherwise healthy people to those who are at higher risk of complications.
Cons of the Flu Shot
The influenza vaccine should not be recommended for all people. This is because influenza infection is generally not serious, and it would be enormously expensive and logistically difficult to vaccinate everyone each year. However, certain groups of people who are at increased risk of complications should be vaccinated to prevent death and/or hospitalization. This group includes all people over age 65, all people who live or work in homes for the elderly or chronically ill, all individuals with chronic cardiac or respiratory illnesses (such as asthma) and all individuals with chronic medical disorders.
Even if you get the flu shot you may still get the flu. The viruses that cause influenza change rapidly and flu vaccines are developed each year to protect people from the strains expected to be most prevalent. Studies of healthy young adults have shown flu vaccine to be 70 to 90% effective. In the elderly and those with certain long-term medical conditions, the flu shot is often less effective in preventing illness. However, in the elderly, flu vaccine is very effective in reducing hospitalization and death from flu-related causes.
The flu vaccine contains mercury from thimerosal, a preservative added to prevent bacterial contamination. Mercury is toxic to the brain, nerve cells, arterial linings and has been linked to an increase in the risk of Alzheimer's disease, dementia, memory loss, depression, anxiety, ADD, heart disease, hypertension and birth defects.
According to the world's leading immunogeneticist, Dr. Hugh Fudenberg, if an individual has had five consecutive flu shots, his or her chances of getting Alzheimer's disease is 10 times higher than if they had one, two or no shots. This is seemingly related to the gradual accumulation of mercury in the brain which has been found to cause cognitive dysfunction.
All viruses in the vaccine are dead, so it is not possible to get the flu from the vaccine, however, soreness at the injection site or aches and low-grade fever may be present for several days.
Elderly individuals who receive the flu shot are more likely to be diagnosed with dementia or stroke.
As with any drug or vaccine, there is a possibility that allergic reactions, more serious reactions or even death may occur after receiving the injection.
Who Should Not Have the Flu Shot?
The following groups should not get the flu vaccine or should do so only after consultation with their primary care providers:
- People with an allergy to chickens or egg protein
- People with a fever or illness that is more than "just a cold"
- Anyone who has exhibited a moderate to severe reaction after a previous influenza shot
- Pregnant women or women attempting to conceive. The flu shot contains a mercury preservative. Mercury has been linked to an increased incidence of birth defects.
- Anyone who has ever been paralyzed due to Guillain-Barre syndrome
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Confused?
It is proven that individuals who exercise, take vitamin C, manage stress, live a healthy lifestyle and subsequently have a healthy immune system have a decreased susceptibility to colds and the flu. As an alternative to the flu shot, work on preventing the flu by strengthening your immune system.
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12 Strategies to Strengthen Your Immune System
By Linda B. White, M.D.
Eating a variety of colorful vegetables is just one easy (and delicious!) way to naturally strengthen your immune system.
Infections are as inevitable as death and taxes. You spend your first years catching (or being caught by) colds, influenza and strep throat. You sniffle, scratch, cough, vomit, ache, sweat and shiver. Your immune system remembers the microbes it has encountered and protects you the next go around. At the other end of life, your immune system wearies from years of fighting. In that great expanse of active, productive life in between, you still get colds and flus and "stomach bugs." You may wonder why you are sick more or less often than your partner, co-workers and neighbors. You may wonder why one person hacking on the airplane successfully sickens the passenger to his right but not the one to his left. The answer is that not all immune systems function alike. A number of factors affect immune system health. Some you can't control: The very young and the very old are vulnerable. Surgery and wounds give microbes a chance to sneak into the inner sanctum. Other risks include chronic disease, poverty, stress, living with lots of other people (dormitories, low-income housing), and drinking tap water (with its local microbes) in many foreign countries. Fortunately, there are ways you can strengthen your immune system.
1: Eat Like Peter Rabbit.
Malnutrition impairs immune function. French fries, soft drinks and bourbon don't build strong white blood cells either. No, it's those virtuous, self-righteous diets high in fruits, vegetables and nuts that promote immune health, presumably because they're rich in nutrients the immune system requires. Adequate protein intake is also important; the source can be plant or animal.
Medicinal mushrooms such as shiitake, maitake and reishi contain beta-glucans (complex carbohydrates) that enhance immune activity against infections and cancer and reduce allergies (cases of inappropriate immune system activity). While studies have focused on purified mushroom extracts, fresh shiitake and maitake (also called "hen of the woods") mushrooms are delicious sauteed in a little olive oil.
One substance to avoid is simple sugar. Brigitte Mars, herbalist and author of The Desktop Guide to Herbal Medicines, notes that sugary foods and juices impair immune function; research bears her out.
If you're a new mother, breast milk provides essential nutrients and immune system components to your developing child. Compared with formula-fed babies, those nourished at the breast have fewer serious infections.
2: Stress Less.
When you're stressed, your adrenal glands churn out epinephrine (aka, adrenaline) and cortisol. While acute stress pumps up the immune system, grinding long-term duress taxes it. For instance, psychological stress raises the risk for the common cold and other viruses. Less often, chronic stress can promote a hyper-reactive immune system and aggravate conditions such as allergies, asthma and autoimmune disease.
While most of us can't move into a spa, we can learn to save our stress responses for true emergencies and not fire them up over stalled traffic, bad hair days and aphids on the begonias. Stress-reducing activities such as meditation produce positive changes in the immune system. Massage has shown to improve immune function in studies of Dominican children with HIV. Quiet music can aid recovery from everyday hassles and may therefore buttress immune function.
3: Move Your Body.
Moderate exercise discharges tension and stress and enhances immune function. In a 2006 study, researchers took 115 obese, sedentary, postmenopausal women and assigned half of them to stretching exercises once a week and the other half to at least 45 minutes of moderate-intensity exercise five days a week. At the end of the year-long study, the stretchers had three times the rate of colds as the moderate-exercise group.
4: Sleep Soundly.
Sleep is a time when growth-promoting and reparative hormones knit up the raveled sleeve of daily life. Sleep deprivation activates the stress response, depresses immune function and elevates inflammatory chemicals (which cause you to feel ill).
Chronic sleep deprivation raises the risk of the common cold. Mothers whose small children interrupt their sleep have more respiratory infections, particularly if those wee ones go to day care. In one study, after researchers inoculated volunteers' noses with cold viruses (a reward was involved), men and women who habitually slept less than seven hours a night were almost three times more likely to develop a cold than those who slept eight hours or more.
5: Socialize More.
People with richer social lives enjoy better health and longevity than loners do. You may think that the more people you interact with, the more chances you have for picking something up. Not so. Again, researchers blew cold viruses up people's noses and sent them into the world. Compared with the lone wolves, the social butterflies were less susceptible to developing common colds, and, if they did get sick, they had fewer symptoms for a shorter period of time.
Many of us count furred and feathered companions as friends, and it turns out they do us a world of good. Animals such as dogs and horses get us outside exercising. Stroking an animal stirs feelings of well-being, lowers blood pressure and, according to recent research, boosts the immune system. Researchers assigned college students to pet either a stuffed dog or a live dog. Those who petted a real dog had a significant increase in levels of salivary IgG, an antibody (immune protein) that fights infection. Those who petted the stuffed dog just felt silly.
6: Make more love.
While having lots of friends is healthy, science also shows that intimate, sexual relationships have immune system perks. Michael Castleman, renowned health writer and publisher of Great Sex After 40, writes, "A 2004 study shows that the close contact of lovemaking reduces the risk of colds." Specifically, this study found that college students who had sex once or twice a week had 30 percent more salivary IgA antibody than those who had sex infrequently.
7: Shun Tobacco Smoke.
Tobacco smoke triggers inflammation, increases respiratory mucus, and inhibits the hairlike projections inside your nose (cilia) from clearing that mucus. Children and adults exposed to tobacco smoke are more at risk for respiratory infections, including colds, bronchitis, pneumonia, sinusitis and middle ear infections.
8: Consume Friendly Bacteria.
Beneficial microorganisms colonize our intestinal, lower urinary and upper respiratory tracts. They outcompete bad "bugs" and enhance immune function. You can consume such bacteria in the form of live-cultured products such as yogurt, sauerkraut and kimchi. Probiotic supplements, available at natural food stores, may reduce the risk of antibiotic-induced diarrhea, viral diarrhea, vaginitis and respiratory infections.
9: Expose Yourself.
Vitamin D plays a number of roles in promoting normal immune function. Vitamin D deficiency correlates with asthma, cancer, several autoimmune diseases (e.g., multiple sclerosis), and susceptibility to infection (including viral respiratory infections). One study linked deficiency to a greater likelihood of carrying MRSA (methicillin-resistant Staphylococcus aureus) in the nose.
Unfortunately, nearly one-third of the U.S. population is vitamin D deficient. Because few foods contain much vitamin D, your best bet is to regularly spend short periods of time in the sun (without sunscreen), and to take supplements in northern climes during the colder months. Guidelines for the Recommended Daily Allowance (RDA) of vitamin D, currently set at 400 IU/day, are being revised. Experts predict that the new RDA will be about 1,000 IU/day (25 ug/day).
10: Choose Vitamin and Mineral Supplements Wisely.
Studies link deficiencies of zinc, selenium, folic acid, and vitamins A, B6, C, D and E to reduced immune function. But scientists have yet to pinpoint exact levels of these nutrients for optimal immune function, much less whether dietary supplementation really helps the average, well-fed American. For instance, research on vitamin C for prevention and treatment of the common cold has been inconclusive. Some micronutrients, notably vitamin A, can be toxic in overdose. Excessive levels of zinc paradoxically suppress immune function. A varied, plant-based diet and a good multivitamin supplement should meet your needs.
11: Immunize Yourself.
Routine vaccinations have had a huge impact on reducing, and in many cases nearly eradicating, a number of infectious diseases. Most immunizations occur during childhood. Vaccinations for adults to consider include yearly influenza vaccines, tetanus boosters, the shingles vaccine for people 60 and up, and the pneumococcus vaccine for people over the age of 65. For more information, check with the Centers for Disease Control.
12: Familiarize Yourself With Immune-Enhancing Herbs.
A long list of medicinal plants contain chemicals that enhance immune system activity, including echinacea, eleuthero (also called Siberian ginseng), ginseng (Asian and American), astragalus, garlic, and shiitake, reishi and maitake mushrooms.
Garlic is the favorite choice of many. In addition to boosting the immune system, it's anticancer and antimicrobial against a variety of bacteria, viruses, fungi and parasites. Key ingredients don't survive cooking, so add a clove or two of raw, minced garlic to meals just before serving.
When someone in my family sniffles, I make an immune soup based on a recipe Brigitte Mars shared with me years ago:
Pretend you're making chicken soup. Sauté onions, shiitake mushrooms and chicken, adding just enough water to keep the chicken from drying out.
Remove the chicken when it's cooked and set aside. Add fresh vegetables such as carrots and celery. Cover with plenty of water. Toss in three or four astragalus roots (the pressed roots, available in natural foods stores or from online herb retailers such as Mountain Rose Herbs and Pacific Botanicals). Toward the end of cooking, add Italian seasonings (thyme, rosemary, oregano), which are tasty and antimicrobial, and the chopped, cooked chicken. Before serving, add fresh, pressed garlic (one to two cloves per person) and remove the astragalus roots.
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Natural Ways to Boost Your Immune System
How to: Grow Greens Indoors
It may dark and chilly in November in most parts of the country, but a true gardener will always find a way to keep growing plants, even under adverse conditions. Gardeners in warm climates are enjoying the fall planting and harvest season, while gardeners in cold climates still continue to harvest winter hardy vegetables such as kale, carrots, leeks and Brussels sprouts. These will survive temperatures in the 20 degree F range with some winter protection.
But if you crave delicate salad greens and don't live where you can grow them outdoors in winter, or you live in an apartment with little room to garden outdoors, there's another option. The solution is indoor gardening under lights. By using an artificial light setup and growing plants in pots or containers, you can harvest lettuce, spinach and other greens right through the winter instead of paying through the nose for these salad greens at the grocery store. All it takes is a little preparation to grow your own salad garden this winter. Here's how:
- Purchase a lighting system for growing greens indoors. It's best to have a 2 or 4 fluorescent bulb fixture with a mix of cool white and warm white bulbs. You can also purchase grow lights or the newer T-5 lights. Though more expensive than other fluorescent lights, T-5 lights are skinnier than regular fluorescent bulbs, use less energy, last longer and deliver more of the light spectrum plants need to grow. Replace fluorescent bulbs when they turn black at the ends. The black color indicates the light output has greatly diminished.
- Choose greens that are adapted to indoor growing. Loose leaf lettuce varieties, such as 'Black Seeded Simpson' and 'Tom Thumb', baby spinach varieties, such as 'Catalina', arugula and mesclun mix are some good choices. You can even experiment with growing radishes, Asian greens and broccoli as micro-greens, or grow herbs indoors. See the links at the end of this article for more information on these crops.
- For containers, use plastic pots, seed trays or even the clear plastic containers in which lettuce is sold at grocery stores. If using recycled plastic containers such as the lettuce containers, be sure there are plenty of drainage holes in the bottom.
- Add moistened soilless potting soil or seed starting mix to the pots and trays so it's about 3 to 4-inches deep.
- Sow seeds 1/2 to 1inch apart in rows in the trays, or sow a few seeds per small pot. Some lettuce varieties need light to germinate, so barely cover the seeds with potting soil and mist with water.
- Cover the trays and pots with a black plastic bag and place them in a warm (70F) spot. Often the top of the refrigerator is a good place to hasten germination since it stays consistently warm.
- Check the pots and trays daily. Once the seeds begin to germinate, remove the plastic bag and place the seedlings under lights.
- Position the lights just above the growing seedlings. Using a timer, keep the lights on during the day for 14 hours/day.
- Move the lights up as the seedlings grow, keeping them about 6-inches from the top of the plants. If you place your hand on top of the greens and it's warm, then the bulb is too close and may burn the tender foliage.
- If you're growing lettuce, spinach and mesclun mix for baby greens, begin to harvest when they are 4-inches tall (20-30 days after seeding), cutting them with a scissors one inch above the soil. Allow the greens to grow back again for a second and even third harvest.
- If you're growing lettuce and spinach into larger heads, transplant individual seedlings into 4 to 6-inch diameter pots. Let them grow to full size (45-60 days), then remove the entire plant when harvesting.
- Keep the pots watered and fertilize weekly with a dilute organic fertilizer. While fish emulsion is a great organic fertilizer for greens, be aware if you use fish emulsion indoors, the smell will permeate the house. Consider other organic fertilizer options if that's a concern.
- Once you harvest the large heads of lettuce and spinach, or the baby greens begin to get tough and woody, compost the plants and potting soil and start over again. You can repeat sowing a greens garden 2 to 3 times in winter to have a continual salad crop. You can even time your greens garden to be in full harvest for the holidays or a special birthday. Imagine a celebration featuring greens grown indoors in your house.
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Grow Your Own Tomatoes Indoors This Winter
By Robert Cox
Colorado State University Cooperative Extension Agent, Horticulture
Tomatoes here, tomatoes there, tomatoes everywhere. When we're adrift in a sea of tomatoes, why a column about growing more tomatoes?
Think about the taste of those store-bought facsimiles you purchased last January and you have the answer. Those pale, hard, tasteless, imitations made you long for the real thing. This winter, you can have it.
You don't need a green thumb or a greenhouse to grow vine-ripened tomatoes indoors. "Window-sill" tomatoes will do well in 6-inch pots filled with good potting soil. You'll also need the right tomato seed, seed starter mix, fertilizer, and plant stakes. Presto! Tomato salad comin' up!
Window-sill tomatoes are smaller than their outdoor relatives -- quarter-to-half-dollar-size. But don't let their small size fool you -- they come with a big tomato taste. They aren't "slicers," but they are perfect for salads or snacks.
Here's how to grow a winter tomato garden:
You can grow one plant in a 6-inch pot or two plants in larger pots. For a continuous winter supply, start one or two new plants from seed every two weeks. Recommended varieties are Pixie, Patio, Toy Boy, Small Fry or Tiny Tim. These varieties will produce small plants, but they still may need to be staked, especially when they begin to bear fruit. Quarter-inch dowels make good stakes.
Germinate seeds in a small pot with starter mix. Plant seeds about 1/4 inch deep and water. Keep starter mix moist but not soggy. Germination should occur in 5 to l0 days.
Transplant from starter mix into potting soil when seedlings are about 3 inches tall. Fertilize regularly, but lightly, beginning about two weeks after transplanting. Water plants thoroughly, but not too frequently. A catch pan under the pot will keep windowsills dry.
When plants bloom, help Mother Nature along: Tap the main stem and larger side branches with your finger. This moves the plant slightly and encourages pollination. As you tap the plant, you might see a small cloud of pollen falling from the open flowers.
Turn plants occasionally, so all sides get a fair share of sunlight. After each plant has provided a bumper crop and has become unproductive, cut it off at the base, saving the potting soil for future transplants. Toss the old plant in the compost pile.
THE STORY BEHIND STORE-BOUGHT TOMATOES
To satisfy our year-round demand, commercial suppliers plant tomato varieties suitable to production and shipping needs. Often, these tomatoes lack the taste, color or texture that most people prefer. To better withstand shipping, they usually are picked at the "mature green" stage. To complete ripening at their destination, they are gassed with ethylene, a natural plant hormone that is part of the ripening process.
A United States Department of Agriculture study found that ethylene gas has no effect on the tomato's nutritional quality. Surprisingly, such tomatoes provide only slightly less beta carotene, which the body converts to vitamin A, and vitamin C than the tastier vine-ripened fruits. One 5-ounce tomato -- whether home-or-greenhouse grown -- provides a third of our daily needs for these vitamins, along with some iron, fiber and B vitamins.
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Grow a tomato plant indoors in winter
Eco Friendly Ventilation
James Murray
We all know what its like to be in an office environment or home without air conditioning, particularly if there's an untypical heat wave across the UK, but how can we ensure when designing and constructing an ecologically sound building, that the ventilation system is eco-friendly?
The simplest solution is to ensure windows, and ideally doors, are open as wide and as often as possible. There is, after all nothing more ecologically friendly than encouraging the air to circulate within a building by allowing as much to come in, and as much to escape, as possible.
Ensuring that the walls themselves are breathable is crucial too. A breathable wall simply means that air can pass through, while insulating at the same time.
Efficient systems of ventilation
Despite this, most buildings still need some sort of internal system to circulate air within them, to stop the build-up of stale air, to provide a healthier living space. Studies within hospitals have pointed some of the blame for recent outbreaks of disease at the air conditioning systems. Most of these systems, while controlling the air temperature in a regulated way, simply recycle the same stale air, and potentially air-borne parasites and gases are blasted at already sick and immune-weakened patients.
Other studies have also shown that people living in a naturally ventilated building feel more comfortable than in one that is air conditioned. But the site of the building, with factors such as topography and the proximity of other buildings and main roads, may well prevent this from being feasible.
Newer air-conditioning systems, such as the innovative eco-design being pioneered and installed at the Sandbrook primary school in the North-West Borough of Rochdale, have been developed to shift air currents that become blocked, and release air through specially designed wind towers. A series of louvered vents in each classroom connect to these, which expel air outward. Such systems can also store heat from the circulating air and use it as and when required, in conjunction with solar heating systems.
A key factor in the design of this system is that it uses less electricity, and is therefore more energy efficient. This is crucial in terms of the whole system being regarded as an ecologically friendly method of ventilation. It is just as important to have energy efficient methods of air circulation, as it is to have a good supply of fresh air to a building.
http://www.sustainablebuild.co.uk/
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Natural Ventilation
by Andy Walker
Introduction
Almost all historic buildings were ventilated naturally, although many of these have been compromised by the addition of partition walls and mechanical systems. With an increased awareness of the cost and environmental impacts of energy use, natural ventilation has become an increasingly attractive method for reducing energy use and cost and for providing acceptable indoor environmental quality and maintaining a healthy, comfortable, and productive indoor climate rather than the more prevailing approach of using mechanical ventilation. In favorable climates and buildings types, natural ventilation can be used as an alternative to air-conditioning plants, saving 10%-30% of total energy consumption.
Natural ventilation systems rely on pressure differences to move fresh air through buildings. Pressure differences can be caused by wind or the buoyancy effect created by temperature differences or differences in humidity. In either case, the amount of ventilation will depend critically on the size and placement of openings in the building. It is useful to think of a natural ventilation system as a circuit, with equal consideration given to supply and exhaust. Openings between rooms such as transom windows, louvers, grills, or open plans are techniques to complete the airflow circuit through a building. Code requirements regarding smoke and fire transfer present challenges to the designer of a natural ventilation system. For example, historic buildings used the stairway as the exhaust stack, a technique now prevented by code requirements in many cases.
Description
Natural ventilation, unlike fan-forced ventilation, uses the natural forces of wind and buoyancy to deliver fresh air into buildings. Fresh air is required in buildings to alleviate odors, to provide oxygen for respiration, and to increase thermal comfort. At interior air velocities of 160 feet per minute (fpm), the perceived interior temperature can be reduced by as much as 5°F. However, unlike true air-conditioning, natural ventilation is ineffective at reducing the humidity of incoming air. This places a limit on the application of natural ventilation in humid climates.
A. Types of Natural Ventilation Effects
Wind can blow air through openings in the wall on the windward side of the building, and suck air out of openings on the leeward side and the roof. Temperature differences between warm air inside and cool air outside can cause the air in the room to rise and exit at the ceiling or ridge, and enter via lower openings in the wall. Similarly, buoyancy caused by differences in humidity can allow a pressurized column of dense, evaporatively cooled air to supply a space, and lighter, warmer, humid air to exhaust near the top. These three types of natural ventilation effects are further described below.
Wind
Wind causes a positive pressure on the windward side and a negative pressure on the leeward side of buildings. To equalize pressure, fresh air will enter any windward opening and be exhausted from any leeward opening. In summer, wind is used to supply as much fresh air as possible while in winter, ventilation is normally reduced to levels sufficient to remove excess moisture and pollutants. An expression for the volume of airflow induced by wind is:
Qwind = K x A x V, where
Qwind = volume of airflow (m³/h)
A = area of smaller opening (m²)
V = outdoor wind speed (m/h)
K = coefficient of effectiveness
The coefficient of effectiveness depends on the angle of the wind and the relative size of entry and exit openings. It ranges from about 0.4 for wind hitting an opening at a 45° angle of incidence to 0.8 for wind hitting directly at a 90° angle.
Sometimes wind flow prevails parallel to a building wall rather than perpendicular to it. In this case it is still possible to induce wind ventilation by architectural features or by the way a casement window opens. For example, if the wind blows from east to west along a north-facing wall, the first window (which opens out) would have hinges on the left-hand side to act as a scoop and direct wind into the room. The second window would hinge on the right-hand side so the opening is down-wind from the open glass pane and the negative pressure draws air out of the room.
It is important to avoid obstructions between the windward inlets and leeward exhaust openings. Avoid partitions in a room oriented perpendicular to the airflow. On the other hand, accepted design avoids inlet and outlet windows directly across from each other (you shouldn't be able to see through the building, in one window and out the other), in order to promote more mixing and improve the effectiveness of the ventilation.
Buoyancy
Buoyancy ventilation may be temperature-induced (stack ventilation) or humidity induced (cool tower). The two can be combined by having a cool tower deliver evaporatively cooled air low in a space, and then rely on the increased buoyancy of the humid air as it warms to exhaust air from the space through a stack. The cool air supply to the space is pressurized by weight of the column of cool air above it. Although both cool towers and stacks have been used separately, the author feels that cool towers should only be used in conjunction with stack ventilation of the space in order to ensure stability of the flow. Buoyancy results from the difference in air density. The density of air depends on temperature and humidity (cool air is heavier than warm air at the same humidity and dry air is heavier than humid air at the same temperature). Within the cool tower itself the effect of temperature and humidity are pulling in opposite directions (temperature down, humidity up). Within the room, heat and humidity given off by occupants and other internal sources both tend to make air rise. The stale, heated air escapes from openings in the ceiling or roof and permits fresh air to enter lower openings to replace it. Stack effect ventilation is an especially effective strategy in winter, when indoor/outdoor temperature difference is at a maximum. Stack effect ventilation will not work in summer (wind or humidity drivers would be preferred) because it requires that the indoors be warmer than outdoors, an undesirable situation in summer. A chimney heated by solar energy can be used to drive the stack effect without increasing room temperature, and solar chimneys are very widely used to ventilate composting toilets in parks.
An expression for the airflow induced by the stack effect is:
Qstack = Cd*A*[2gh(Ti-To)/Ti]^1/2, where
Qstack = volume of ventilation rate (m³/s)
Cd = 0.65, a discharge coefficient.
A = free area of inlet opening (m²), which equals area of outlet opening.
g =9.8 (m/s²). the acceleration due to gravity
h = vertical distance between inlet and outlet midpoints (m)
Ti = average temperature of indoor air (K), note that 27°C = 300 K.
To = average temperature of outdoor air (K)
Cool tower ventilation is only effective where outdoor humidity is very low. The following expression for the airflow induced by the column of cold air pressurizing an air supply is based on a form developed by Thompson (1995), with the coefficient from data measured at Zion National Park Visitor Center (PDF 3.4 MB). This tower is 7.4 m tall, 2.4 m square cross section, and has a 3.1 m² opening.
Qcool tower =0.49 * A* [2gh (Tdb-Twb)/Tdb]1/2, where
Qcool tower = volume of ventilation rate (m³/s)
0.49 is an empirical coefficient calculated with data from Zion Visitor Center, UT, which includes humidity density correction, friction effects, and evaporative pad effectiveness.
A = free area of inlet opening (m²), which equals area of outlet opening.
g =9.8 (m/s²). the acceleration due to gravity
h = vertical distance between inlet and outlet midpoints (m)
Tdb = dry bulb temperature of outdoor air (K), note that 27°C = 300 K.
Twb = wet bulb temperature of outdoor air (K)
The total airflow due to natural ventilation results from the combined pressure effects of wind, buoyancy caused by temperature and humidity, plus any other effects from sources such as fans. The airflow from each source can be combined in a root-square fashion as discussed in ASHRAE (2009). The presence of mechanical devices that use room air for combustion, leaky duct systems, or other external influences can significantly affect the performance of natural ventilation systems.
B. Design Recommendations
The specific approach and design of natural ventilation systems will vary based on building type and local climate. However, the amount of ventilation depends critically on the careful design of internal spaces, and the size and placement of openings in the building.
- Maximize wind-induced ventilation by siting the ridge of a building perpendicular to the summer winds.
- Approximate wind directions are summarized in seasonal "wind rose" diagrams available from the National Oceanographic and Atmospheric Administration (NOAA). However, these roses are usually based on data taken at airports; actual values at a remote building site can differ dramatically.
- Buildings should be sited where summer wind obstructions are minimal. A windbreak of evergreen trees may also be useful to mitigate cold winter winds that tend to come predominantly from the north.
- Naturally ventilated buildings should be narrow.
- It is difficult to distribute fresh air to all portions of a very wide building using natural ventilation. The maximum width that one could expect to ventilate naturally is estimated at 45 ft. Consequently, buildings that rely on natural ventilation often have an articulated floor plan.
- Each room should have two separate supply and exhaust openings. Locate exhaust high above inlet to maximize stack effect. Orient windows across the room and offset from each other to maximize mixing within the room while minimizing the obstructions to airflow within the room.
- Window openings should be operable by the occupants.
- Provide ridge vents.
- A ridge vent is an opening at the highest point in the roof that offers a good outlet for both buoyancy and wind-induced ventilation. The ridge opening should be free of obstructions to allow air to freely flow out of the building.
- Allow for adequate internal airflow.
- In addition to the primary consideration of airflow in and out of the building, airflow between the rooms of the building is important. When possible, interior doors should be designed to be open to encourage whole-building ventilation. If privacy is required, ventilation can be provided through high louvers or transoms.
- Consider the use of clerestories or vented skylights.
- A clerestory or a vented skylight will provide an opening for stale air to escape in a buoyancy ventilation strategy. The light well of the skylight could also act as a solar chimney to augment the flow. Openings lower in the structure, such as basement windows, must be provided to complete the ventilation system.
- Provide attic ventilation.
- In buildings with attics, ventilating the attic space greatly reduces heat transfer to conditioned rooms below. Ventilated attics are about 30°F cooler than unventilated attics.
- Consider the use of fan-assisted cooling strategies.
- Ceiling and whole-building fans can provide up to 9°F effective temperature drop at one tenth the electrical energy consumption of mechanical air-conditioning systems.
- Determine if the building will benefit from an open- or closed-building ventilation approach.
- A closed-building approach works well in hot, dry climates where there is a large variation in temperature from day to night. A massive building is ventilated at night, then, closed in the morning to keep out the hot daytime air. Occupants are then cooled by radiant exchange with the massive walls and floor.
- An open-building approach works well in warm and humid areas, where the temperature does not change much from day to night. In this case, daytime cross-ventilation is encouraged to maintain indoor temperatures close to outdoor temperatures.
- Use mechanical cooling in hot, humid climates.
- Try to allow natural ventilation to cool the mass of the building at night in hot climates.
- Open staircases provide stack effect ventilation, but observe all fire and smoke precautions for enclosed stairways.
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Natural ventilation in most climates will not move interior conditions into the comfort zone 100% of the time. Make sure the building occupants understand that 3% to 5% of the time thermal comfort may not be achieved. This makes natural ventilation most appropriate for buildings where space conditioning is not expected. As a designer it is important to understand the challenge of simultaneously designing for natural ventilation and mechanical cooling—it can be difficult to design structures that are intended to rely on both natural ventilation and artificial cooling. A naturally ventilated structure often includes an articulated plan and large window and door openings, while an artificially conditioned building is sometimes best served by a compact plan with sealed windows. Moreover, interpret wind data carefully. Local topography, vegetation, and surrounding buildings have an effect on the speed of wind hitting a building. Wind data collected at airports may not tell you very much about local microclimate conditions that can be heavily influenced by natural and man-made obstructions. Hints about what type of natural ventilation strategies might be most effective can often be found in a region's historic and vernacular construction practices.
C. Materials and Methods of Construction
Some of the materials and methods used to design proper natural ventilation systems in buildings are solar chimneys, wind towers, and summer ventilation control methods. A solar chimney may be an effective solution where prevailing breezes are not dependable enough to rely on wind-induced ventilation and where keeping indoor temperature sufficiently above outdoor temperature to drive buoyant flow would be unacceptably warm. The chimney is isolated from the occupied space and can be heated as much as possible by the sun or other means. Air is simply exhausted out the top of the chimney creating suction at the bottom which is used to extract stale air.
Wind towers, often topped with fabric sails that direct wind into the building, are a common feature in historic Arabic architecture, and are known as "malqafs." The incoming air is often routed past a fountain to achieve evaporative cooling as well as ventilation. At night, the process is reversed and the wind tower acts as a chimney to vent room air. A modern variation called a "Cool Tower" puts evaporative cooling elements at the top of the tower to pressurize the supply air with cool, dense air.
In the summer, when the outside temperature is below the desired inside temperature, windows should be opened to maximize fresh air intake. Lots of airflow is needed to maintain the inside temperature at no more than 3-5 °F above the outside temperature. During hot, calm days, air exchange rates will be very low and the tendency will be for inside temperatures to rise above the outside temperature. The use of fan-forced ventilation or thermal mass for radiant cooling may be important in controlling these maximum temperatures.
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