Friday, June 29, 2007

Heart Muscles Do Not Get Tired During Exercise

A healthy heart is so strong that it is almost never a cause of tiredness during exercise. Tiredness during exercise comes from your muscles. They run out of fuel or out of oxygen. Skeletal muscles use both fat and sugar for energy. When your muscles run out of their stored sugar supply, called glycogen, they cannot contract and function adequately. You feel tired, your muscles hurt and you have difficulty coordinating them. On the other hand, your heart muscle gets energy directly from fat and sugar in your blood and even from a breakdown product of metabolism called lactic acid. It is virtually impossible for the heart muscle to run out of fuel unless you are starving to death.

A healthy heart doesn't run out of oxygen either. Oxygen comes to the heart directly through arteries on its outside surface. If these arteries are not plugged up with plaques, they are large enough to supply all the oxygen that the heart can possibly need. However, fatty plaques in arteries can block the flow of blood. When the heart does not get enough blood, it will hurt and can start to beat irregularly. Exercise won't make a healthy heart hurt. If you develop chest pain during exercise, something is wrong and you need to check with a doctor immediately. More

Thursday, June 28, 2007

Chronic Stuffy Nose Often Caused by Fungi

If your nose is stuffy during the pollen seasons in the spring and fall, check with an allergist. Allergy injections can help control your symptoms. If your stuffy nose started after puberty, you don't have allergies and your nose is stuffy 12 months a year, allergy injections usually are ineffective. Chronic sinus infections with nasal polyps have been considered incurable because doctors didn't have the foggiest idea what causes them, but researchers at the Mayo Clinic found fungi in 96 percent of people with chronic sinusitis. Nasal polyps are small finger-like, fluid-filled blisters, often associated with asthma and serious reactions to aspirin.

The most common fungi are alternaria, penicillium, cladosporium, aspergillus, candida and fusarium. A sinus cat scan will tell whether a person has a sinus infection. If the cat scan shows fluid levels indicating a sinus infection, the doctor should order a fungus culture of the nose. If the culture is positive for fungi, the doctor should consider treatment with antifungal medication, even though there are no good studies to show the fungal medicines cure sinusitis, because the present treatment of cortisones works only in the short run, and shortens life by causing osteoporosis, high blood pressure and obesity. If the fungus infection is positive, the person should be treated with the appropriate anti-fungal medication such as Sporanox, Lamisil or Diflucan. People with positive skin tests to molds are the ones most likely to suffer asthma attacks so severe that they have to be hospitalized (14).

If your nose is stuffy during the pollen seasons in the spring and fall, check with an allergist. Allergy injections can help control your symptoms. If your stuffy nose started after puberty, you don't have allergies and your nose is stuffy 12 months a year, allergy injections usually are ineffective. Antihistamines and decongestant pills help to control your symptoms a little. Cortisone-type pills are highly effective but have side effects, such as obesity and osteoporosis. Cortisone-type nasal sprays are safer than the pills. So, doctors are continuously searching for better ways to treat people with chronically stuffy and running noses.

Surgeons can remove nasal polyps, but the polyps usually return within a few weeks. People with nasal polyps should never take aspirin as most will eventually develop shortness of breath, itching or increased nasal stuffiness when they take it. Until recently, the only effective treatment was cortisone-like injections and pills, such as prednisone, and antibiotics to treat the infections associated with polyps. However, cortisone-type pills and injections can make you fat, weaken your bones and rarely cause hip damage, so doctors try to avoid this treatment and prescribe cortisone-type pills for only a week or two, followed by cortisone-type nasal sprays to slow the return of the polyps. Polyps may be caused by infection with mycoplasma bacteria or fungi and may be treated most effectively by antibioitcs such as doxycycline, Zithromzx or Roxithromycin, or by fungi medication such as fluconazole. However, this is controversial and not accepted by many doctors; discuss it with your doctor. More information and journal references

Wednesday, June 27, 2007

Eating Before Swimming Won't Cause Stomach Cramps

If you are going to exercise vigorously for more than an hour, you need to eat before you exercise or your muscles and liver will run out of sugar and you will tire earlier. Your brain gets more than 98 percent of its energy from sugar in your bloodstream. But there is only enough sugar in your bloodstream to last three minutes. So you liver has to constantly release sugar from its cells into your bloodstream. There is only enough sugar in your liver to last about an hour when you exercise vigorously. Eating before exercising can help you to exercise longer. If you do not eat before you exercise for more than an hour, and during exercise that lasts more than two hours, your liver will probably run out of sugar. Your blood sugar level can drop, and you will feel terrible fatigue and tiredness.

Whenever your stomach fills with food, its muscles contract and require large amounts of blood. When you exercise vigorously, your heart pumps large amounts of blood to your skeletal muscles. If your heart is not strong enough to pump blood to both your stomach and your skeletal muscles, blood is shunted from your stomach muscles, the muscles lack oxygen, lactic acid builds up in muscles and they start to hurt. However, most people can exercise after eating without suffering stomach cramps because their hearts are strong enough to pump blood to both their exercising muscles and their stomach muscles.

Another theoretical concern is that eating sugar before you exercise will cause your blood sugar level to rise and your pancreas to release insulin, which will cause your blood sugar to drop too low so you will feel tired. However, the major cause of tiredness that you feel in your muscles during exercise is lack of stored sugar in muscles. Taking any extra calories before and during exercise helps to preserve the sugar that is stored in muscles and help you to exercise longer. If you are going to exercise for more than an hour, eat or drink anything you like before and during your exercise. Most people will not get stomach cramps while exercising, no matter what or when they eat.

Tuesday, June 26, 2007

Prevent Diabetes: Pistachio Nuts May Help

One third of Americans will become diabetic, regardless of their country of origin. Most doctors feel that a person's diet has a lot to do with whether he or she becomes diabetic, and the most likely cause is foods that cause a high rise in blood a sugar after you eat them. A study from the University of Toronto shows that pistachio nuts (and probably most other nuts) help to keep blood sugar levels from rising too high after eating meals that normally cause a high rise in blood sugar (reported at the Experimental Biology meeting, Washington DC, May 2007).

The Glycemic Index is a listing how much specific foods raise blood sugar. Foods with a high glycemic index are supposed to be off limits to diabetics, and perhaps they should be restricted by people who are likely to become diabetic. Not all doctors accept this theory because the glycemic index of foods can vary from person to person and even vary in the same person at different times. For example, the only places that you can store extra sugar in your body are in your muscles, liver and bloodstream. When you exercise, your muscle are empty of their stored sugar supply. Sugar passes from your intestines into your bloodstream and then directly into your muscles, so your blood sugar levels do not rise too high. However, when you are not exercising, your muscles are full of sugar and the sugar in your bloodstream has no place to go, so blood sugar levels rise and stay elevated.

If you want to prevent diabetes, reduce your intake of refined carbohydrates such as sugared water, sugared foods and flour. When you do eat refined carbohydrates, eat them with something that contains fat, such as nuts, to cause the sugar to remain in your stomach longer. Exercise every day to empty your muscles of sugar, so blood sugar will have a place to go and not rise to the high levels that can cause cell damage. More on preventing and treating diabetes; free weekly newsletter

Monday, June 25, 2007

High Blood Pressure in Children Increasing

The incidence of high blood pressure in children is increasing, probably because of the increased incidence of obesity. Unlike high blood pressure in adults, doctors can almost always find the cause of hypertension in a child. It may be kidney disease, blocked blood vessels, hormone abnormalities, pinching of the main blood vessels, or obesity. Many children with untreated high blood pressure have evidence of heart damage called left ventricular hypertrophy.

Whatever the cause, your child must learn how to control weight by exercising more and taking in fewer calories by limiting foods made with refined carbohydrates, saturated fats or partially hydrogenated oils. He or she will certainly need medication, at least until blood pressure is reduced or a cause is found. The drugs with the fewest side effects are ACE-inhibitors and angiotensin receptor blockers.

Children need at least 90 minutes of exercise a day to avoid heart disease when they are older. The old guidelines recommending 30 minutes of exercise three times a week, or even an hour a day do not appear to be adequate for preventing obesity and heart disease.
Journal reference for this article; more on children and exercise to prevent obesity.

Friday, June 22, 2007

Health Claims on Food Labels: Not So Reliable

The U.S. Food and Drug Administration has loosened restrictions on how much scientific proof is required before possible health benefits appear on food labels. For example, the FDA now allows sellers of certain nuts to claim that "Scientific evidence suggests, but does not prove, that eating 1.5 ounces per day of some nuts, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease." Sellers of seafood that is rich in omega-3 fatty acids will want to claim that their products prevent heart attacks, and so forth, so we will probably see a proliferation of these statements on food labels in the years ahead.

A manufacturer cannot claim that a product prevents heart attacks just because it contains nuts. For example, putting nuts in ice cream will not allow a manufacturer to claim that ice cream with nuts prevents heart attacks. The claims are supposed to help you understand that the specific food only helps to prevent heart attacks when a person does not take in too many calories, does not eat too much saturated and partially hydrogenated fats, and does eat lots of vegetables and other foods derived from plants. You cannot say that eating nuts prevents heart attacks, but you can say that eating nuts as part of a healthful diet helps to prevent heart attacks.

Many products that advertise zero grams of trans fat on their labels still have partially hydrogenated oils in their ingredient lists, which means that they DO contain trans fats despite their label claims.

US labeling laws allow a manufacturer to claim ZERO if there is less than one-half gram (.5g) of partially hydrogenated oil per serving. That doesn't sound like much, but if a serving size is one teaspoon or one cracker, it can add up to a lot of trans fats in a tub of margarine, a bowl of cereal or a bag of chips. I think the claims are deceptive, but the manufacturers are not breaking the law. Use the list of ingredients as your source of information, not the nutrition panel or the "Zero Trans Fat" claims. If the words "partially hydrogenated" appear in the list of ingredients, look for another brand.

Many manufacturers are developing new formulations of their popular brands that contain NO partially hydrogenated oils. Seek these products out and vote with your pocketbook.

Thursday, June 21, 2007

Salt restriction to lower blood pressure: an ongoing controversy

Nowhere in medicine is there more confusion than the issue of salt as a cause of high blood pressure. At a recent meeting of the American Association of Clinical Endocrinologists, Dr. Abdul-Rahman of Newark, Delaware reported that people who lowered blood insulin levels had a significant reduction in high blood pressure even though they also markedly increased their salt intake. Journal reference

These obese patients increased their daily salt intake from less than two grams a day to more than 20 grams a day. They avoided starchy and sugary foods and lost around 12 pounds in six weeks. They did not count calories. Their average blood sugars dropped from 106 to 98, average fasting insulin from 21 to 14 mu/ml and average diastolic blood pressure from 96 to 88. Some of the patients were able to stop their blood pressure drugs. This study and others show that high blood insulin levels are an important cause of high blood pressure, and that you can lower insulin levels by avoiding refined carbohydrates and losing weight. Instead of salt restriction, I recommend a modified DASH diet to all my patients.

Exercisers need salt, particularly in warm weather. When you exercise for more than three hours, you should take in salt as well as fluids. Taking in fluid without also taking in adequate amounts of salt dilutes the bloodstream, so that the concentration of salt in the blood is lower than that in brain cells. This causes fluid to move from the low-salt blood into the higher-salt brain causing the brain to swell which can cause seizures and death. Taking in extra salt during prolonged exercise increases thirst so you drink more fluids, and prevents blood salt levels from dropping so low that you become tired, develop muscle cramps, and can even die. Furthermore, without salt you do not recover as quickly and are more likely to be injured or tired all the time. More on hyponatremia

Wednesday, June 20, 2007

Asthma inhalers: how they improve athletic performance

Drugs called beta-2 agonists, such as salbutamol, salmeterol and terbutaline, open the closed lungs of asthmatics and help them to breathe. They also increase the amount of fat in the bloodstream to increase energy sources of exercising muscles, help to preserve the muscles’ store of sugar, and help muscles to contract with more force. The common inhaled asthma medication called albuterol has been shown to improve athletic performance.

These asthma medications are potent stimulants, so they could cause irregular heart beats. It is illegal for Olympic competitors to take albuterol pills. However, asthmatics need their medications, so the Olympic medical committee allows asthmatics to take these same medications by inhaler, provided that a doctor informs the Olympic committee beforehand that the athlete is an asthmatic and is taking this medication. Needless to say, there are unprecedented numbers of asthmatics registered with the Olympic committee and other authorities in sports that monitor drug use. More on asthma

Jumping rope for fitness: pros and cons

To use rope-jumping for fitness, you need to be skilled enough to jump continuously for twenty to thirty minutes, and jumping that long and fast requires that you be in good shape. All you need is a ten-foot rope. The ends of the rope should barely reach your armpits when you stand on the middle of it. You don't need special shoes, but sandals or loose shoes are likely to cause tripping. Start out by spinning the rope forward so you can see it as it passes. Bend your knees to absorb the shock of landing and protect the force of your feet striking the ground. To keep yourself from falling, bend slightly forward at the waist. Start out gradually and work up to thirty minutes three times a week.

The fitness benefit from any exercise depends on how fast you move, whether it's jumping, running, cycling or any other activity. Jumping rope has to be a vigorous sport, because you must spin the rope at least 80 times a minute to keep it from tangling. Most people use more energy when they jump rope than when they run. Jumping 80 times a minute uses the same amount of energy as running a mile in less than eight minutes, which is a rapid pace for most people. If you enjoy rope jumping, do it at a speed that is comfortable to you and stop when you feel discomfort. More on how to start an exercise program; the real meaning of fitness

Monday, June 18, 2007

Inability to chew properly can cause weakness, frailty in older people

Many older people are so weak that they move slowly, are terribly uncoordinated and often fall and break their bones. A study from France shows that part of this problem can be caused by faulty chewing (American Journal of Clinical Nutrition, May 2007).

As almost all people age, they lose muscle tissue and become weaker. Muscles are built from the protein digested from food. The authors measured protein absorption in older people by feeding them radioactive leucine and then measuring the amount in their blood. Half the subjects had normal teeth and half had full dentures. Those who lost all their teeth had far lower absorption of the protein that they ate, absorbing only 30 percent compared to 48 percent for those who had their own teeth. This study shows that the ability to chew food affects nutritional status and may be a major factor in the health of elderly people.

Loss of muscle mass in older people weakens immunity as well. As you age, you lose your ability to kill germs because of lack of muscle. When germs get into your body, you must make white blood cells and proteins called antibodies to kill them. Antibodies and cells are made from protein and the only place that you can store extra protein is in your muscles. When you have large muscles, you have a ready source of protein to make antibodies and cells. When you have small muscles, you have a very limited source of amino acids to make protein, so your immunity may be inadequate to kill germs. More

Sunday, June 17, 2007

Do Not Limit Calories Before Competition

Most athletes know that lack of fluids weakens and tires them, so they take adequate amount of fluids, before, during and after competitions. However, many do not know how much they need extra calories. They often are told incorrectly that the human body as so much fat on board that lack of calories is not a significant problem. Researchers at the University of Wales in the United Kingdom found that moderate calorie restriction two days prior to competition slows down endurance far more than reduced fluid intake over that same period (Medicine and Science in Sports and Exercise, February 2007). Moderate dehydration does not harm performance until a person becomes severely dehydrated. On the other hand, lack of calories stops you cold in your tracks.

Dehydration does not limit endurance until a person loses enough fluid to decrease blood volume, which takes a long time. However, endurance during exercise depends on having enough sugar stored in your muscles. When you exercise, you get energy from fat and sugar stored in muscles, fat and sugar from the bloodstream, and to a lesser extent, from protein. When your muscles run out of their stored sugar, they can hurt and you will find it more difficult to coordinate them. This happens no matter how much energy you have stored in body fat, which is virtually limitless during almost all athletic events. So a major nutritional principle of endurance exercise is to store as much sugar in muscles as possible and preserve that sugar supply for as long as possible. When you reduce calorie intake, you reduce your stored muscle sugar supply, so you should never fast or reduce calorie intake prior to athletic competition. In a few sports, athletes must lose weight so they can compete in a lower weight class, but they can compensate to some extent by eating as much as possible just before they start their competition. More

Thursday, June 14, 2007

Low Blood Sugar Symptoms Require an Explanation

When blood sugar levels drop, you may feel anxious, shaky, sweaty, hungry, a tingling in your skin or your heart may beat rapidly. More severe symptoms include confusion, a sensation of warmth, weakness or fatigue, loss of memory and in its extreme, seizures and passing out. As you suffer repeat attacks of low blood sugar, they affect you less and your symptoms lessen.

If your doctor tells you that you suffer from hypoglycemia, he must then tell you the cause because low blood sugar is the result of something going wrong in your body. It is not a cause. Your brain gets more than 98 percent of its energy from sugar in your bloodstream. There is only enough sugar in your bloodstream to last about three minutes, so your liver constantly releases sugar from its cells into your bloodstream. But your liver can store only enough sugar to last 12 hours at rest, so it must manufacture new sugar from protein and other energy stores.

There are two types of low blood sugar. First when your blood sugar rises too high, causing your pancreas to release a large amount of insulin that drops your blood sugar too low, and second, a slow drop in blood sugar caused by your liver running out of stored sugar. Doctors used to think that insulin-induced hypoglycemia follows meals and that your liver running out of sugar doesn't follow meals, but they now know that both types can occur any time.

It is almost impossible to diagnose hypoglycemia by drawing blood after you suffer an attack of dizziness, weakness or fainting because your body produces adrenalin immediately and raises blood sugar levels to normal before your doctor can draw blood. It can be diagnosed by feeding you lots of sugar and measuring your blood sugar level every half hour for several hours. If you indeed suffer from hypoglycemia, your doctor then has to find a cause that could include a damaged liver, an inadequate amount or an excess of many different hormones, a tumor or glandular abnormality. Journal references

Fluids Early in Competition Improve Performance

A study from the University of North Carolina at Chapel Hill shows that drinking fluids earlier can improve performance more than taking them later. Seven highly-trained male triathletes, aged 18 to 35 years, were tested during two simulated Olympic-distance triathlons. They took a full glass of water at 8, 16, 24, and 32 kilometers, and this was compared to taking the same drink 2, 4, 6 and 8 kilometers later in the event (at 10, 20, 30, and 40 kilometers).

As you would expect, opening swim times for 1500 meters were similar between trials; as were the second event (40-km cycling) times, but the third event (10-km run) times were faster when the athletes took food and drink earlier. Dehydration does not harm an athlete's performance until he lacks a large amount of water and his blood volume is depleted significantly. That explains why the athletes' performance was not harmed until the third event of the three-event competition.

When you exercise hard or in hot weather, you sweat and breathe off huge amounts of fluid. Losing fluid reduces blood volume to make you tired. Anyone who exercises vigorously can increase their endurance by taking in fluids, and competitive athletes can increase their endurance by taking in extra fluids just before the start of their event and drinking fluids regularly during events that last more than an hour. Be sure to replace salt as well as fluid you lose when you sweat, and don’t force yourself to drink large amounts of water. More on hyponatremia; journal reference; recommended books on fitness and nutrition

Tuesday, June 12, 2007

New Study Shows Mediterranean Diet Best for Heart Attack Prevention

Here is one more study that shows obesity, heart attacks, strokes, high cholesterol and high blood pressure are influenced by lifestyle. Researchers at the University of Athens, in Greece showed that a person's chances of becoming diabetic or developing high blood pressure, heart attacks or obesity can be predicted by the diet he eats (Preventive Medicine, April 2007).

The authors developed a diet score ranging from 0–55 to check adherence to the Mediterranean diet. The gave scores of 0 to 5 each for consuming non-refined cereals, fruits, vegetables, legumes, olive oil, fish and potatoes). They awarded scores of 0 to 5 for eating these foods: never, rare, frequent, very frequent, weekly and daily. They subtracted points for eating red meat, poultry and full fat dairy products. You guessed it. Those on healthy diets were at very low risk for these conditions, while those with low scores were at high risk.

This study confirms many others that advise you to eat plenty of fruits, vegetables, whole grains, beans, seeds, and nuts, and some fish and shellfish. For a perfect score, follow my modified DASH diet guidelines

Monday, June 11, 2007

Thirty Minutes Three Times a Week is Not Enough

If you have heard that you get maximum benefit from exercising for 30 minutes three times a week, you've been given bad advice. Exercise can help to lower high blood pressure, cholesterol, insulin levels and body fat. However, for most people, it takes a lot of exercise to see these results.

A recent study shows that many people need to exercise a very long time just to achieve a normal life expectancy (Current Opinion in Lipidology, February 2007). One out of three Americans can expect to develop diabetes, and most of these people have bodies that cannot respond adequately to insulin because they eat too much food and do not exercise enough. This causes their blood sugar to rise too high after meals, which, in turn, causes the pancreas to put out huge amounts of insulin that makes them even fatter. Exercise can keep blood sugar from rising too high after meals. When muscles are full of sugar, blood sugar goes from the intestines into the bloodstream and spikes to high levels. On the other hand, when muscles are empty of sugar, sugar goes from intestines into the blood and then directly into muscles to prevent the spike. It doesn't matter much whether you exercise before or after eating, because both help to prevent the spike in blood sugar that follows meals.

This study found that increasing the intensity of exercise reduces insulin resistance. If you store fat primarily in your belly, rather than your hips, the odds are overwhelming that you are either diabetic or pre-diabetic, and without changing your lifestyle, you will not live your normal lifespan. If your doctor clears you for exercise, start an exercise program. If your exercise program does not get rid of your belly fat, increase both the length and the intensity of your workouts. More on how to start an exercise program

Thursday, June 07, 2007

Ammonia odor caused by common stomach bacteria

Until recently, doctors couldn't explain why some people smell like ammonia when they exercise. A report from Japan tells us why.

To smell like ammonia, you have to eat a lot of protein or be infected with a germ called helicobacter. Many weightlifters eat tremendous amounts of protein because they mistakenly think that it will make them stronger. The food you eat contains carbohydrates, fats and proteins. Of the three, only protein contains nitrogen. The body has no way to store extra protein, so when you take in more protein than your body needs, your liver knocks nitrogen off the protein and the nitrogen is eventually converted to ammonia and passes through the sweat glands and kidneys.

Some people smell like ammonia when they do not take in large amounts of protein. An article in the European Journal of Gastroenterology and Hepatology showed that many people who smell like ammonia are infected with helicobacter, a bacteria that knocks nitrogen off protein also. When helicobacter grows in your stomach and intestines, it causes ulcer symptoms characterized by belching, burping, a sour taste in your mouth and a burning pain that often become more severe when you are hungry and better when you eat. More than 80 percent of people who have duodenal ulcers are infected with this bacteria. If your sweat smells like ammonia, ask your doctor to do a blood test for helicobacter. If you are infected, you can be cured with a one week course of antibiotics. Check with your doctor. More on helicobacter; journal references

Wednesday, June 06, 2007

Blood Pressure-Lowering Diet as Effective as Drugs

Scientists at the National Institutes of Health have shown why the DASH diet lowers high blood pressure to normal in more than 80 percent of people with high blood pressure. On the DASH diet you eat lots of leafy green vegetables that are rich sources of nitrites, common salts that your bloodstream, can be converted to nitric oxide which opens blood vessels.

This means that nitrites could be a new treatment for high blood pressure, heart attacks, sickle cell disease, and blocked arteries leading the heart, brain and legs. Hemoglobin is the red pigment in red blood cells that carries oxygen in your bloodstream. When hemoglobin releases oxygen, it converts nitrites to nitric oxide, to widen blood vessels. Blood nitrite levels are low in patients with high blood pressure.

However, at high concentrations nitrites are toxic, so you must take limited amounts. Leafy greens are rich sources of safe amounts of nitrites. The nitrites go into the bloodstream, where exposure to oxygen converts nitrites to nitrous oxide which dilates arteries and lowers high blood pressure. Hypertensives should also eat lots of other plants for the same reason and cut back on meat and chicken, that are rich sources of sodium that can raise high blood pressure.

The modified DASH diet I recommend will also lower cholesterol and help you lose excess weight; it is the most effective diet for preventing or controlling diabetes.
Journal reference

Tuesday, June 05, 2007

Master Athletes Age Better than Non-Exercisers

Almost 50 percent of Americans die of heart attacks and strokes, diseases that are associated with a faulty diet and lack of exercise. Almost 80 percent are overweight or obese, which is also associated with lack of exercise. Yet only 13 percent of people over 65 engage in vigorous physical activity three or more days a week. Among those over 75, only six percent exercise regularly.

Master athletes are older men and women who compete in sports at a very high level, no matter how old they are. They are healthier than age-matched people in virtually every category that has been measured. Of course they are more fit, as measured by their maximal ability to take in and use oxygen. They have lower cholesterols, comparable to those of people in their twenties. They have lower glucose tolerance and HBA1C screening tests for diabetes. They have lower waist-to-hip ratios, decreasing their risk for metabolic syndrome and diabetes. They have far less body fat.

Many people who have never exercised are afraid to start an exercise program. They should check with their doctors and get a special exercise stress test. If they pass the test, they are at low risk for complications during exercise. Then they should join an organized exercise program. One study showed that 85 percent of middle aged Americans who start an exercise program quit in the first six weeks. Those most likely to remain exercised with a spouse or friend, used a personal trainer, or participated in classes such as aerobic dancing or spinning. Successful lifelong exercisers usually make their sports part of their social life, not just a tedious chore. Journal reference; more on how to start an exercise program

Sunday, June 03, 2007

Hot-Weather Exercisers Need Salt to Avoid Fatigue

Fatigue during hot-weather exercise is caused by lack of water, salt, sugar or calories. Of the four, exercisers are most ignorant of their sodium needs. A study from The University of Otago in New Zealand shows that taking a salty drink prior to competition can help an athlete to exercise longer and harder (Medicine and Science in Sports and Exercise, January, 2007; and Clinical Journal of Sport Medicine, January 2007). Athletes who took the salty drink had larger blood volumes and greater endurance. Salt makes you thirsty earlier so you drink more, and salt in your body holds water so you have more water available to meet your needs.

In 1942, James Gamble of Harvard Medical School was hired to establish guidelines for soldiers fighting in the very hot climate of the South Pacific. He found that the only mineral needed for exercise in hot weather is sodium, found in common table salt. As a result of his studies, salt tablets were recommended for people who worked or exercised in hot weather, but since they caused stomach problems and because of concerns about high blood pressure, salt tablets were abandoned in the 1970s.

Salty drinks taste bad, so it is easier to meet your needs with salted foods. If you plan to exercise for more than a couple hours in hot weather, drink one or two cups of the liquid of your choice each hour and eat a salty food such as salted peanuts.
Fitness newsletter

Friday, June 01, 2007

Muscle Soreness is Necessary for Improvement

Your muscles should feel sore on some days after you exercise. If you go out and jog the same two miles at the same pace, day after day, you will never become faster, stronger or have greater endurance. If you stop lifting weights when your muscles start to burn, you won't feel sore on the next day and you will not become stronger. All improvement in any muscle function comes from stressing and recovering. On one day, you go out and exercise hard enough to make your muscles burn during exercise. The burning is a sign that you are damaging your muscles. On the next day, your muscles feel sore because they are damaged and need time to recover. Scientist call this DOMS, delayed onset muscle soreness.

It takes at least eight hours to feel this type of soreness. You finish a workout and feel great; then you get up the next morning and your exercised muscles feel sore. We used to think that next-day muscle soreness is caused by a buildup of lactic acid in muscles, but now we know that lactic acid has nothing to do it. Next-day muscle soreness is caused by damage to the muscle fibers themselves. Muscle biopsies taken on the day after hard exercise show bleeding and disruption of the z-band filaments that hold muscle fibers together as they slide over each other during a contraction.

Scientists can tell how much muscle damage has occurred by measuring blood levels of a muscle enzyme called CPK. CPK is normally found in muscles and is released into the bloodstream when muscles are damaged. Those exercisers who have the highest post-exercise blood levels of CPK often have the most muscle soreness. Using blood CPK levels as a measure of muscle damage, researchers have shown that people who continue to exercise when their muscles feel sore are the ones most likely to feel sore on the next day.

Many people think that cooling down by exercising at a very slow pace after exercising more vigorously, helps to prevent muscle soreness. It doesn't. Cooling down speeds up the removal of lactic acid from muscles, but a buildup of lactic acid does not cause muscle soreness, so cooling down will not help to prevent muscle soreness. Stretching does not prevent soreness either, since post-exercise soreness is not due to contracted muscle fibers.

Next-day muscle soreness should be used as a guide to training, whatever your sport. On one day, go out and exercise right up to the burn, back off when your muscles really start to burn, then pick up the pace again and exercise to the burn. Do this exercise-to-the-burn and recover until your muscles start to feel stiff, and then stop the workout. Depending on how sore your muscles feel, take the next day off or go at a very slow pace. Do not attempt to train for muscle burning again until the soreness has gone away completely. Most athletes take a very hard workout on one day, go easy for one to seven days afterward, and then take a hard workout again. World-class marathon runners run very fast only twice a week. The best weightlifters lift very heavy only once every two weeks. High jumpers jump for height only once a week. Shot putters throw for distance only once a week. Exercise training is done by stressing and recovering. Weekly fitness newsletter