Sunday, November 25, 2007

Mental Fatigue from Low Blood Sugar Levels

Exercisers and athletes can expect to feel fatigued when their blood sugar levels drop. Researchers at Loughborough University, UK showed that athletes who did not take sugar during soccer competition lasting 90 minutes felt more tired, had less competitive desire, and had far lower blood sugar levels than athletes who took a sugared drink every 15 minutes during their game.

Your brain gets more than 98 percent of its energy from sugar in the bloodstream. However there is only enough sugar in the bloodstream to last about three minutes. The liver must constantly release sugar into the bloodstream, but there is only enough sugar in the liver to last eight hours during rest and far less than that during exercise. So athletes who do not take a source of sugar during events lasting more than an hour can suffer the psychological effects of low blood sugar levels what include a mental feeling of fatigue and lowered competitive desire.

In another study, researchers at the University of Waterloo in Canada showed that taking sugar 30 minutes after starting to cycle and every 15 minutes afterwards increases strength, speed and endurance when exercising fairly intensely at 60 percent of maximal oxygen uptake. Muscles burn carbohydrates, fats, and protein for energy. Carbohydrates (sugars) require the least amount of oxygen for conversion to energy, which allows you to move faster with less effort. Athletes use sugared drinks, power bars or candy bars, concentrated sugared gels, cookies and almost any other source of carbohydrates during prolonged competition. It is possible to take in too much sugar and get a high rise in blood sugar if you are not exercising intensely, but this is rarely a concern for competing athletes. Competition takes great concentration, and eating and drinking are distractions that most athletes limit as much as possible. Journal references

Wednesday, November 21, 2007

Angioplasty Patients Can and Should Exercise

If you have had angioplasty and your doctor does not already have you in as supervised exercise program, ask when you can start. In one study from Bern, Switzerland, researchers showed that a three-month exercise program can increase blood flow to the heart in people who already have their coronary arteries blocked by plaques (European Journal of Cardiovascular Prevention and Rehabilitation, April 2007). The study participants were selected from patients who had stents inserted to widen blockages in their coronary arteries. The longer and harder the subjects were able to exercise, the greater the increase in blood flow.

The blood flow to the heart muscle comes primarily from arteries on the outside surface of the heart. Chest pain with exercise is usually caused by narrowing of these arteries, which prevents adequate amounts of blood to flow to the heart muscle. The heart muscle then suffers from lack of oxygen and hurts. A heart attack occurs when plaques that coat the inner lining of arteries leading to the heart break off and travel down the ever- narrowing artery until they completely obstruct the flow of blood to a part of the heart muscle. Then part of the heart muscle that is deprived of oxygen dies and a person suffers a heart attack. People with damaged coronary arteries are at higher risk for heart attacks during exercise, so the study participants were checked for blood flow to the heart before and after the program, and were monitored during exercise by professional personnel.

Monday, November 19, 2007

Smarter Baseball Players Live Longer

Smarter baseball players live longer, according to researchers at the Department of Economics at Shippensburg University in Pennsylvania. The authors collected data on players who were born between 1945 and 1964 and found that the death rate for players who attended only high school was almost twice as high as those who went to college. They also found what high body fat levels were associated with premature death. The study was published in the journal Death Studies.

The good news for all athletes is that the baseball players had only 31 percent of the death rate of the general population. The lower death rate in the more highly educated players is probably due to their increased awareness of life style factors linked to premature death, such as smoking, promiscuity, obesity, eating a high-fat, high-refined carbohydrate diet that is low in vegetables, and so forth.

Sunday, November 18, 2007

Small Lifestyle Changes Combat Obesity in Children and their Families

Pediatricians at the University of Colorado at Denver have shown that very small changes in lifestyle can help stem the epidemic of obesity in North American children. Families of overweight children, seven to fourteen years of age, were asked to make two lifestyle changes: 1) to walk an additional 2000 steps per day, as measured by pedometers, and 2) to eliminate 100 calories per day by replacing a source of dietary sugar with a non-caloric beverage or sweetener. At the end of the six-month trial, most of the children had lost weight and the parents had no significant weight gain. Journal reference

Obesity comes from eating too much and exercising too little. It is associated with increased risk for heart attacks, strokes, kidney failure, certain cancers, diabetes, and premature death. Various studies show that 80 percent of American adults are overweight, and the greatest rate of increase in obesity is occurring in children.

Recent research suggests that one important cause of obesity may be sugared drinks, because calories in liquid form do not suppress appetite as effectively as calories in solid food. Giving toddlers fruit juices and other sugared drinks to quench thirst can form a lifelong habit that sets them up for obesity. Teach your children to drink water or other non-calorie drinks when they are thirsty. The only time it makes sense to consume sugared beverages is during prolonged exercise, where they are a convenient source of energy for muscles that have been depleted of their sugar.

Thursday, November 15, 2007

Orthotics may relieve foot pain from running or exercising

People with high arches are at increased risk for foot pain and stress fractures of their bones of their feet because their feet are usually very poor shock absorbers. A report in Cochrane Database of Systematic Reviews (October 2007) shows that custom orthotics can help. When you run rapidly, your foot hits the ground with a force equal to about three times body weight. This force can break bones and damage muscles, nerves, and tendons. So most people land on the outside bottom of their feet and roll inward. This is called pronation which helps absorb some of the shock of the foot striking the ground. However, pronation can cause pain from stretched ligaments (plantar fasciitis), pulled tendons (tendinitis), or pinched nerves (neuromas). Some people are at high risk for injury because they have very stiff ankles that prevent their feet from rolling in normally. These people usually have normally-formed arches and only appear to have high arches.

Orthotics are special custom arch supports that help to absorb shock and prevent foot pain. To see if orthotics are likely to help you, ask your podiatrist to strap your foot with a special taping procedure called a low-dye strap. If this reduces the pain, you probably will benefit from custom orthotics. If orthotics do not cure your problem, pick another sport with limited foot impact such as cycling, swimming or rowing. Other foot problems

Wednesday, November 14, 2007

Muscle Cramps from Exercise: Causes and Prevention

Exercisers are often told that muscle cramps are caused by lack of salt (sodium) or low potassium. However, recent studies show that athletes in endurance events who suffer cramps usually have normal sodium and potassium levels. A review of the current literature from Buenos Aires, Argentina shows that doctors don't know very much about exercise-induced muscle cramps. The most common cause appears to be muscle damage. Athletes may be able to prevent cramps by slowing down when they feel the muscle pulling and tightening, and picking up the pace only when the muscle feels good again. Journal reference

Cramps may occur as a side effect of drugs used for high cholesterol, high blood pressure or diabetes. Oral contraceptives, various other drugs or alcohol can also cause muscle cramps. If you suffer from recurrent muscle cramps that cannot be explained, check with your doctor. Possible causes include pinched nerves, Parkinson's disease, hypothyroidism, diabetes, narrowed arteries, low blood mineral levels, or metabolic diseases that cause muscle damage. However, most exercisers who experience exercise- associated muscle cramps do not suffer from disease and can usually prevent cramps by slowing down when their muscle start to feel tight. Athletes are usually not willing to do this during competition, so they will continue to suffer from occasional cramps and work them out as they occur. More

Friday, November 09, 2007

Measurable Fat Loss from Exercise

If you weigh yourself before and after an hour or two of exercise, the difference is likely to be fluid loss. However, in events lasting several hours or even several days, measurable fat loss can occur. At a competitive 12-hour indoor stationary bicycle marathon, one athlete took fluids and food throughout the entire competition, and still lost 2.64 pounds. Of this weight loss, 1.98 pounds was due to loss of fat. His calculated muscle weight increased by 1.46 pounds due to damage to the muscle cells, which results in fluid retention in the cells. Journal reference

During vigorous cycling, an athlete can burn between 600 and 1000 calories per hour, so this cyclist probably used more than 9000 calories in his 12-hour event. That is equal to the amount of energy needed to form almost three pounds of fat. He lost only two pounds of fat because of the prodigious amount of food and drink he took in during the marathon. You can lose fat during a single exercise session, but you have to be in extremely good shape and exercise for a very long time to accomplish this. For most exercisers, true weight loss will be measured over weeks or months.

Tuesday, November 06, 2007

Saunas May Benefit Athletes and Exercisers

For many years I have believed that heating muscles in a hot tub or sauna after exercise interferes with muscle contractions and hampers muscular endurance. However, a study from the University of Otago in New Zealand shows that taking a sauna after workouts for three weeks helped athletes to exercise longer to exhaustion.

Trained runners sat in a humid sauna for 30 minutes at 89.9 degrees centigrade immediately after exercising, 12 times in three weeks. They then ran as hard as they could on a treadmill for about 15 minutes, to exhaustion. Sauna use increased run time to exhaustion by 32 percent, which would equal an improvement of approximately two percent in a full-length endurance time trial. Their blood volumes increased by more than seven percent, and higher blood volume increases endurance. If further research confirms these findings, athletes will be advised to use saunas or hot tubs after their workouts for several weeks before competition. Journal reference

Monday, November 05, 2007

Exercise More Important than Weight Loss for Diabetes Prevention

Exercise is even more important than weight loss for prevention or control of diabetes, according to a report from the Australian National University in Canberra. Dr. Richard Telford concludes that obesity is associated with, but does not cause, diabetes, heart disease and premature death. The health benefits of exercise include increasing cells' ability to respond to insulin, lowering blood sugar levels, and preventing all the side effects of diabetes. Weight loss is not necessary for a person to gain these benefits from an exercise program. Journal references

Most cases of Type II diabetes are caused by the body's inability to respond to insulin. Strengthening muscles makes cells more responsive to insulin. Your ability to respond to insulin depends on the ability of muscles to burn oxygen without producing excessive free radicals (called oxidative capacity). When your body converts food to energy, it produces free radicals that can damage the DNA in your cells to shorten life. Exercise causes cells to burn food for energy more efficiently, without producing large amounts of free radicals.

Thirty-five percent of Americans today can expect to become diabetic. To help prevent diabetes or heart disease, most people should exercise for about an hour a day, alternating vigorous and easy days. If they still have high blood sugar levels, they probably need to exercise more and may also need to take medications. More on treatment of insulin resistance

Friday, November 02, 2007

Caffeine May Prevent Dementia

Caffeine may protect against loss of memory or thinking skills in older women, according to a study published in Neurology. The researchers studied cognitive decline, dementia and caffeine intake of 4,197 women and 2,820 men aged 65 and over in three French cities for four years. They tested the participants' cognitive skills at the start of the study and again at years two and four.

The results showed that compared to women who drank only one cup a day or less, women who drank three or more cups of coffee or tea a day had a 33 per cent reduced risk of decline in verbal retrieval over the four years. The protective effect of caffeine appeared to increase with age, rising from a 27 per cent reduced risk for women aged 65 to 74, to 70 per cent for women aged 80 and over. No link between caffeine and cognitive decline was found in men, nor was caffeine consumption found to affect the incidence of dementia over the four years of the study. Before you increase your coffee intake, note that other studies suggest that caffeine can raise blood sugar and blood pressure. The question of benefits or harm from caffeine is far from settled. Journal reference; more on caffeine