Air Pollution Should Not Keep You From Exercising

It's healthful to exercise and harmful to breathe polluted air, so how can you decide whether you are doing more harm than good? The worst time for pollution is when clouds cover the sky and automobiles fill the roads. Automobile exhaust fumes are the principal source of air pollution in most cities, and overlying clouds increase pollution. Usually the sun's rays heat the ground to warm air closest to the ground. Hot air rises, taking large amounts of pollutants skyward. On air inversion days, the clouds prevent the sun's rays from getting through to the ground, so the air near the ground is not heated, remains colder and doesn't rise, causing the air with its pollutants to remain close to the ground.

Air pollutants such as carbon monoxide, ozone, carbon dioxide, and sulfur dioxide can damage your lungs. When you exercise, you breathe more deeply and more frequently so that you breathe in more pollutants. However, you don't retain more pollution. Bicycle riders in rush hour downtown Washington traffic breathe in more carbon monoxide than car riders do, but have lower blood levels of carbon monoxide. So keep exercising, but if possible, try to avoid heavily trafficked streets, and exercise before the heavy morning traffic peak or at least two hours after the evening rush hour ends.
Should you try to breathe only through your nose?

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Portion Sizes Do Matter

Whether or not you are overweight, portion sizes of food are a major factor in determining how much you eat. In a recent study, researchers at Pennsylvania State University in University Park measured how much normal and overweight people ate (Obesity, June 2007). They then fed these people fifty percent larger portions of food at every meal. Both overweight and normal weight people increased their intake of food equally and they continued to eat far more food for the duration of the study.

You might expect that when people overeat, they would eventually reach a point where they feel full and stop taking in too much food. However, this has not been shown to be the case. When people are offered large portion sizes, they continue to eat more food and it doesn't matter whether they were fat or thin when they received the larger portions. More

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Repetition Makes Muscles More Efficient

Training is specific, so the more you practice your sport, the better you are able to do it. That's why triathletes who compete and train in three sports are relatively mediocre in each sport when compared to those who only run, cycle or swim. (Sports Biomechanics, Volume 6, Issue 1, 2007). In this study, elite cyclists produced significantly more effective force on their pedals than triathletes. They had far less wasted side-to-side motion, and they required less oxygen to do the same amount of work.

Repeating the same motion over and over causes your muscles to become more efficient so they can generate more power with less oxygen. For example, when you run, you use your arms to maintain your center of gravity. When your right leg moves forward, so does your left arm; your left leg and right arm move backward. Efficiency requires that you move your body forward with the least motion wasted going side to side, so that the more energy you use to drive your body forward, the less oxygen your muscles require. The same efficiency is required in pedaling a bicycle. You are supposed to move your pedals through a full 360 degrees, rather than just pushing through one phase of pedaling, and you move your body from side to side as little as possible.

In competitive sports today, the best athletes put in the most time training. Runners usually run more than 100 miles a week, cyclists often go over 400 miles a week, and weight lifters spend many hours each day in the gym lifting prodigious amounts of weights. If you want to compete at a high level, you need to spend a lot of time practicing. More on training and fitness

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Muscles Cannot Become Fat

Some people believe that if they build muscles and then stop exercising, the muscles will turn into fat. This is not a reason to avoid exercise, because muscles can't possibly turn to fat. When you exercise, your muscles become larger and stronger because exercise causes extra protein building blocks, called amino acids, to deposit in muscles. All day long, amino acids pass from your muscles into your bloodstream and then back into muscles. Exercise is the major stimulus to force amino acids back into muscles.

When you stop exercising, fewer amino acids go into your muscles so the muscles get smaller. Your body has no way to store extra protein, so amino acids that are not used in your muscles are picked up by your liver, which uses them for energy or converts them into fat for storage. So if you stop exercising, you have to eat less or you will gain weight. But muscles never turn into fat. More on muscles and protein

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Reduce Oxidants Instead of Taking Antioxidants

Instead of taking antioxidants, researchers now think you should aim to prevent your mitochondria from making excessive amounts of oxidants. The cells of your body have tiny chambers in them called mitochondria that help convert food to energy. When they do this, they knock of electrons from nutrients, and these extra electrons eventually end up attached to oxygen. Electron-charged oxygen, called reactive oxygen species or free radicals, then attach to the DNA cells to damage them and shorten your life.

At this time, scientists have found only one practical way to reduce the amount of oxidants produced by mitochondria: exercise. Vigorous exercise helps the mitochondria burn food more cleanly with the production of fewer oxidants. The same effect can be accomplished with severe calorie restriction, or with chemicals such as resveratrol or dichloroacetate, but the results of these studies in animals have not yet been successfully applied to humans.

Here's another study showing that taking antioxidant vitamins does not prevent heart attacks (Archives of Internal Medicine, August 2007). 8,171 women over the age of 40, all with a history of heart disease or with three or more risk factors for that disease (high blood pressure, diabetes or high cholesterol) were randomly assigned into groups and given either 500 milligrams of ascorbic acid (vitamin C) every day, 600 units of vitamin E every other day or 50 milligrams of beta carotene every other day. None of the antioxidant vitamins, either alone or in combination, helped reduce the risk of a heart attack. As of today, there is no evidence that taking antioxidants vitamin pills helps prevent heart attacks. More on cell mitochondria

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Partial Knee Replacement: Less Pain, but Not for Everyone

The ends of bones are soft, so they must be covered with a thick white gristle called cartilage. Many people suffer from knee pain because the cartilage is damaged. They may have osteoarthritis in which the cartilage wears away, or they may have damaged cartilage in an accident or by playing sports. Once damaged, cartilage can never heal; the person spends the rest of his life losing cartilage until the cartilage is completely gone and the knee hurts 24 hours a day.

Until recently, the only effective treatment has been to cut out the ends of the bones of the knee and replace the entire knee joint. Now for some people, a simpler procedure may be effective: partial knee replacement, called unicompartmental knee arthroplasty. The surgeon removes just part of the cartilages and bones on the upper and lower legs on one side of the knee.

However, this procedure is not for everyone. Since partial replacements are more fragile than total knee replacements and do not last as long, the patient should be over 60, not obese and not a vigorous exerciser. All of the knee ligaments should be intact, the other compartments of the knee should not be damaged, and there should be no disease, such as rheumatoid arthritis, that causes progressive joint damage. If a partial knee replacement fails, more extensive surgery will be required for a total knee replacement. If you think you may be a candidate for partial knee replacement, check with an orthopedist with experience in this procedure.

After any surgery on knee cartilage, you must protect that knee for the rest of your life. Running and jumping cause further damage, while pedaling and swimming usually do not. More on total knee replacement; more on arthroscopic knee surgery

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Awkward Running Form Can Be Improved

Many people look terribly uncoordinated when they run. Telling them to change their form will just make them more uncoordinated. If a coach criticizes a team member for poor running form and doesn't correct the underlying causes, the person is likely to become self-conscious about how he or she looks, and run even more slowly. Coordination usually improves just with repeated practice in the chosen sport.

Running form can improve markedly if you can correct muscle imbalances and structural abnormalities with appropriate exercises and perhaps mechanical devices. A coach can videotape the athletes while they run, then review the tape in slow motion to analyze the mechanical defects. For example, leaning forward during running is often caused by weak back muscles, which can be treated with exercises to strengthen the back. Pointing the toes out is often caused by weak lower leg muscles and can be corrected by doing exercises to strengthen the shin muscles. Leaning back on the heels after foot plant can be caused by excessive rolling-in motion of the feet or weak calf muscles.

Treatment often includes special inserts in the shoes and calf strengthening exercises, such as toe raises while holding a heavy weight in the hands. Holding the shoulders up towards the ears during running is usually caused by weak shoulder muscles, which can be corrected by shrugging the shoulders while holding weights. A low knee-lift is often caused by weak quadriceps muscles in the front of the upper leg. The quadriceps can be strengthened by pedaling a bicycle, skating, or running up hills. How to run faster

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