Mitochondria Efficiency: New Key to Aging Well

An exciting report from the University of Washington in Seattle shows how exercise prolongs lives (Exercise and Sport Sciences Reviews, April, 2007). The leading theory for aging is that mitochondria produce oxidants that damage the DNA in cells to shorten life. Mitochondria are parts of cells that convert food to energy. They function by stripping off electrons and protons from food to produce energy. When they do this, they end up with free electrons that eventually attach to oxygen, which produces free radicals that stick to genetic material in cells to cause permanent damage.

As you age, your muscles lose mitochondria and those that remain become smaller so that they produce far more free radicals. Anything that increases the size or number of mitochondria makes them function more efficiently so they produce fewer free radicals. This recent review shows that exercising as you age actually prevents loss of mitochondria and can even make them larger so they produce fewer oxidants.

This report is particularly significant because a recent survey of the world's literature in the Journal of the American Medical Association (February 28, 2007) showed that there is little evidence that taking antioxidant supplements prolongs life, and they may even shorten life. Apparently it is necessary to avoid production of oxidants, not just to take antioxidants as a corrective measure. On the basis of these studies, if you do not already have a regular exercise program, check with your doctor for approval and get started. More

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Diabetes Control or Prevention: Strength Training, Protein Benefits

A study from Purdue University shows that lifting weights and eating extra protein can help to prevent or control diabetes, while enlarging muscles at the same time (American Journal of Clinical Nutrition, May 2007). Thirty-six men and women in their sixties lifted weights three times a week for 12 weeks. They ate either a diet that contained 112 percent of the Recommended Dietary Allowance (RDA) of protein or 150 percent of the RDA. The higher protein group ate more eggs and dairy products.

After 12 weeks, the weight of both groups remained the same, and they gained the same amount of muscle and lost the same amount of fat. Both groups had the same reduced rise in blood sugar after eating a sugared meal. This means that they reduced their chances of becoming diabetic equally. However, the blood insulin levels decreased more in the low-protein group. The authors conclude that older people who consume adequate amounts of protein can use resistance training to increase muscle, lose fat and decrease their chances of becoming diabetic. Your doctor can help you determine how much protein is appropriate for you.
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Interval Training Techniques Can Be Used By Every Exerciser

Athletes train by "stressing and recovering". On one day, they take a hard workout which damages their muscles, on the next day, they feel sore and take easy workouts, and when the soreness goes away, take a hard workout again. They also break down individual workouts into intervals of stress and recovery. After warming up, they increase the intensity of the workout until they feel burning in their muscles, become short of breath, or exceed a certain heart rate. Then they slow down and when they have recovered partially, they increase their intensity again. They repeat these stress and recovery intervals until their muscles start to stiffen and they are then stop the workout. A report from The National Institute for Occupational Safety and Health in Morgantown, West Virginia shows that the shorter the rest during an interval, the longer it takes to recover.

If you are a regular exerciser, you probably have already noticed this in your own body. Runners may take an interval workout of running ten quarter-miles averaging 65 seconds each, with a 110-yard jog lasting three minutes between each hard run. If they shorten their recoveries to two minutes, they tire earlier, their muscles feel sorer afterwards, and it takes them longer to recover. The same applies to weightlifters. A weightlifter may do four sets of ten repetitions of lifting a 150-pound weight, resting for three minutes between each set. If he shortens his interval rest to one minute, he may not be able to finish his workout, feels far more soreness during the workout and will be sore for many days after that workout.

Athletes learn their ideal interval rest durations through trial and error. They may want to rest until their pulses drops enough for them to feel comfortable, or for them to be able to slow breathing rate down towards normal, or wait until their muscles lose soreness and they feel fresh. They do not wait for complete recovery of resting heart or breathing rate, or complete recovery from muscle soreness. Runners and cyclists often use heart rate monitors or a clock to determine when they will do their next interval. Weight lifters usually wait for their bodies to "feel" recovered. You can use whatever yardstick for recovery you like, but if it takes you longer than two days to recover from an interval workout, you are probably exercising too intensely, doing too many repetitions, or not taking a long enough interval rest. Journal reference; free fitness newsletter; more on interval training techniques

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Heatstroke or Just Fatigue? Know the Warning Signs

After you have played a long tennis match on a hot summer day, you feel weaker and less accurate with your shots. The fatigue, muscle weakness, tired aching feeling and decreased coordination that you get in any sport lasting several hours is caused by low levels of fluids, salt or calories. There are no early warning signals. By the time you feel hungry, you have already run low on calories and are ready to crash. By the time you feel thirsty, you are already severely dehydrated and feel weak and tired. By the time you are low on salt, you already have tired, aching or burning muscles; feel weak, tired and dizzy; and may already have muscle cramps.

The primary limiting factor in sports that require great endurance is the time it takes for your heart to pump oxygen in your bloodstream from your lungs into your muscles. A study from the University of Connecticut shows that with dehydration, your heart beats with far less force so it pumps far less blood with each beat, and is unable to bring as much oxygen to your muscles.

You can't depend on thirst to tell you when you lack fluids. Certain brain cells called osmoreceptors tell you when you are thirty, but only after the salt concentration of your blood has risen considerably. When you exercise, you sweat. Sweat contains far more water than salt in comparison to blood. So you lose far more water than salt during exercise and blood levels of salt rise. By the time that a your blood salt concentration is high enough to trip off the osmoreceptors, you are severely dehydrated and it is too late for you to be able to drink enough during exercise to catch up with your water deficit. On the other hand, if you take salt with fluids, then your blood salt levels rise faster and tell you that you are thirsty earlier.

There are other reasons that you should take salt with fluids during prolonged exercise. First, it helps prevent muscle cramps. Remember, during exercise you lose salt and water. If you are replacing only water, you can eventually take in so much water that your salt levels drop to cause muscle cramps. Second, even though salt is a mild diuretic at rest, during exercise it helps your body to retain water. So when you are going to exercise for more than a couple hours, particularly in hot weather, drink small amounts frequently and eat salted foods such as peanuts. Always stop if you feel sick, have chills, headache, severe muscle burning or aching, dizziness, or blurred vision. Seek help if your symptoms do not subside in a few minutes; you could be headed for heat stroke that can kill you. Journal reference for this article; more on heatstroke; more on hyponatremia (too much water)

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Eat during hard exercise, even if you want to lose weight

Don't skip snacks during a long bike ride or other hard exercise, even if weight loss is your goal. You will need to eat food or drink sugared beverages to be able to ride long enough to burn significant calories and lose weight. Your muscles need a constant supply of sugar to keep you going. Cyclists who do not eat run out of their stored muscle sugar in about two hours. When you run out of stored muscles sugar, your muscles hurt and you lose coordination. You will not be able to ride fast because when your muscles run out of their stored sugar, they use fat for energy. Fat is not an efficient source of energy for exercising intensely. You will ride much faster when your muscles are full of sugar. Intense exercise helps you to burn extra calories after you finish your ride. Taking food or sugared drinks during a ride will allow you to exercise intensely enough to increase your metabolism so you will burn extra calories for several hours after you finish your ride.

Eating foods that contain both carbohydrates and proteins during any long competition increases an athlete's endurance more than taking just carbohydrates. When you exercise vigorously for more than two hours, you need to take extra fluid, salt and calories. You should drink whatever fluid tastes best to you, and eat any food that includes salt. Many studies show that taking in extra carbohydrates during an event prolongs endurance, so athletes often eat oranges and other fruits, cookies, sandwiches and other carbohydrate-rich foods. You will have even greater endurance if you also eat some high-protein foods such as cheese, meat, chicken, fish or eggs. During prolonged, intense exercise your muscles are damaged, and the extra protein supplies the building blocks called amino acids that can help to limit muscle breakdown. Fitness newsletter; more on exercise for weight loss

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Recovery Times Do Not Decrease with Age

Many older athletes notice that their muscles weaken with aging, even though their recovery times from hard workouts are the same as when they were younger. A study from Griffith University in Queensland, Australia confirms this. Two groups of experienced cyclists raced in 30-minute time trials on three consecutive days. The first group had an average age of 24 while the second group's average age was 45.

Both groups maintained their average power during the three trials. They had the same amount of muscle damage, measured by the release of a muscle enzyme called CPK. Both groups had a drop in their maximal heart rate of three beats per minute during their third time trial. The maximal voluntary isometric contractions of the quadriceps muscle were the same for both groups. The authors concluded that "high-intensity endurance performance is maintained in both well-trained young cyclists and veteran cyclists following three consecutive days of maximal 30-minute time trials."

Every muscle is made up of millions of individual fibers, as a rope is made of many threads. Each muscle fiber is enervated by a single nerve fiber. The non-preventable result of aging is loss of nerve fibers. With the loss of each nerve fiber during aging, you lose its associated muscle fiber. So aging causes you to have increasingly fewer muscle fibers, which makes you weaker. However, the remaining muscle fibers function as well as those of a younger person. Journal reference for this article; more on recovery times

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Health Benefits of Alcohol Explained by New Study

Various studies have concluded that moderate drinking of alcoholic beverages may improve health and prolong life. However, nobody really knows why this may be true or what doses of alcohol may prevent disease. One possible explanation is given by a study from The University of Sydney in Australia that shows alcoholic beverages help to prevent blood sugar levels from rising too high after meals (American Journal of Clinical Nutrition, June 2007). This means that alcohol could help to prevent the damage caused by high blood sugar levels.

When food reaches the stomach, the pyloric valve closes and does not allow food to enter the intestines until it is turned into a soupy liquid. Anything that keeps food in the stomach longer will help to lower the rise in blood sugar levels. Foods that cause the highest rise in blood sugar include those made with flour or sugar, but when these foods are eaten with fatty foods, they are held in the stomach longer so the rise in blood sugar is blunted. This study shows that alcohol delays the rise in blood sugar in the same way, lowering rise in blood sugar following eating by 16 to 37 percent. This could be the mechanism by which moderate alcohol consumption promotes health.

However, many of the studies proclaiming the health benefits of alcohol have a major flaw. Researchers from the University of Victoria in British Columbia reviewed 54 studies and found that only seven corrected their non-drinking population for people who had to stop drinking for health reasons (Addiction Research and Theory, April 2006).

When you do an epidemiological study to see if alcohol prevents disease, you compare people who drink and those who do not drink. However, many people do not drink because their doctors have told them they have high blood pressure, liver, heart or kidney disease, alcoholism, stomach ulcers, or other major health problems. The Canadian researchers re-analyzed 47 studies that associated wine or other alcohol with a longer life and decreased risk for heart attacks. When the studies were corrected to remove the people who had been ordered to stop drinking for health reasons, they found no difference in death rate between moderate drinkers and those who do not drink at all. It is probably safe to take up to two drinks a day, but be skeptical of studies that say alcohol will prolong your life. Weekly eZine

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