Sunday, September 26, 2010

Control Diabetes with Intense Exercise

"Insulin-insensitive" means that a diabetic has plenty of insulin, but lacks the ability to respond adequately to insulin that their body produces so blood sugar levels remain higher than normal. Twenty-two insulin-insensitive diabetic women participated in a supervised group endurance and resistance exercise program for six months (European Journal of Internal Medicine, October 2010). The more intensely they exercised, the better their bodies responded to insulin. Even those who did not improve their exercise capacity were able to markedly improve their body's ability to respond to insulin.

Diabetic control and cell damage is measured with a blood test called HBA1C that measures sugar stuck on cells. The more they exercised, the lower and better their HBA1C. More than 90 percent of diabetics are insulin-insensitive and have a potentially curable disease. This study shows that the harder diabetics exercise, the better their bodies respond to insulin. Insulin-insensitive diabetes can usually be cured by *losing weight, *avoiding red meat, *avoiding refined carbohydrates when not exercising, *growing larger muscles, *losing body fat, *getting blood levels of vitamin D3 above 75 nmol/L, *eating plenty of vegetables and fruits, and *EXERCISING INTENSELY. (Caution: intense exercise can cause heart attacks in people with blocked arteries. check with your doctor.)

Sunday, September 19, 2010

Cycling Does Not Cause Bone Loss

During a six-day bicycle race, the bones of world class bicycle racers become stronger (Physiologie Appliquée, Nutrition et Métabolisme, June 2010). Bones are constantly changing. Certain cells called osteoblasts take calcium into bones to make them stronger, while other cells called osteoclasts take calcium out of bones to weaken them. During the race, hormones produced by osteoblasts to strengthen bones increased (osteocalcin increased by 300 percent, and C-terminal telopeptide of type I collagen increased by 43 percent).

The theory that cycling weakens bones flies in the face of our current understanding of bone metabolism. Any force on bones increases, and lack of force decreases, the rate of bone formation (Medicine & Science in Sports & Exercise, November 2009). Astronauts in space lose bone because lack of force blocks their ability to respond to Insulin-Like Growth Factor-1 that stimulates bone growth (Journal of Bone and Mineral Research, March 2004). All competitive cyclists know that hammering on the pedals while pulling up on their handle bars puts tremendous force on every muscle and bone in their bodies, and this should stimulate bone growth.

I cannot find any studies showing that cycling weakens bones to increase fracture risk. Some studies show that competitive cyclists have lower bone mineral density in their spines than moderately-active, aged-matched men (Medicine & Science in Sports & Exercise, February 2009; Osteoporosis International Reports, August 2003). These studies have been interpreted to mean that cycling increases risk for bone fractures beyond what you would expect from just falling off the bike. Bone density tests do not measure bones strength. They measure how much bones block X-rays that try to pass through them. The only way to measure bone strength is to see how much force it takes to break a bone.

The most likely explanations for broken bones in cyclists are high-impact crashes and/or lack of vitamin D. I recommend that all cyclists get a blood test called Vitamin D3 in December or January. If it is below 75 nmol/L, they are deficient in vitamin D and at increased risk for breaking bones. To prevent fractures, they should do winter training in the southern sunbelt or take at least 800 IU of Vitamin D3 per day.

A review of 12 controlled scientific studies showed that oral vitamin D reduced non-vertebral and hip fractures in patients over 65 years of age (Evidence-Based Medicine, October 2009). Blood levels of vitamin D below 75 nmol/L cause parathyroid hormone levels to rise too high, which causes osteoporosis. A main function of vitamin D is to increase calcium absorption from the intestines into the bloodstream. When blood levels of vitamin D fall below 75 nmol/L, levels of ionizable calcium drop. This causes the parathyroid gland to produce large amounts of its hormone. Higher than normal blood parathyroid hormone levels take calcium out of bones to cause osteoporosis.

A woman's bones are strongest when she is twenty years old. After that, she continues to lose bone for the rest of her life, and for the first few years of menopause, the rate that she loses bones more than triples. A study from the University of Erlangen in Germany shows that vigorous exercise during the menopause helps prevent osteoporosis (Archives of Internal Medicine, May 2004). In this study, fifty women lifted weights in group training sessions twice a week, and exercised by themselves twice a week. They also took calcium and vitamin D. As their muscles became stronger, so did their bones.

Sprint cyclists, and to a lesser extent distance cyclists, have greater tibia and radius bone strength than controls, with tibial bone measures being well preserved with age in all groups. This suggests that "competition-based cycling and the associated training regimen is beneficial in preserving average or above- average bone strength surrogates into old age in men" (Medicine & Science in Sports & Exercise, March 2009).
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Wednesday, September 15, 2010

How Exercise Prolongs Life by Making You Stronger

As you age, you become progressively weaker. If you exercise regularly, you will not become as weak as other people your age who do not exercise. The same mechanism that makes you stronger will also help you to live substantially longer than people who do not exercise.

Harvard researchers have proven that exercise prevents loss of the connections between nerves and the muscles that they enervate caused by aging (Proceedings of the National Academy of Sciences, published online August 29, 2010). The researchers studied genetically engineered mice with nerve cells that glow in fluorescent colors. Muscles are made up of millions of individual muscle fibers. Every muscle fiber is innervated by a single nerve. If the nerve dies, the muscle fiber innervated by that nerve also dies. With aging, all humans and mice lose nerves that cause their corresponding muscle fibers to die also. However, mice placed on just one month of exercise in later life actually regained some of the lost connections between nerves and muscle fibers. This is the same mechanism that helps revive nerves in the brain to slow down and even stop the loss of mental function associated with aging. Exercise also prevents loss of strength associated with aging that causes falls, broken bones and injuries in older people.

Researchers at The University of Western Ontario in London just reported that competitive runners with an average age of 65 had the same number of nerves and muscle fibers as younger recreational runners, and far more muscle fibers and nerves than non-exercising age-matched controls (Medicine & Science in Sports & Exercise, September 2010).

This helps explain why exercisers live more than 12 years longer than those who do not exercise (British Journal of Sports Medicine, March 2008). Many other studies show that lifelong physically active older mammals have greater numbers of muscle fibers and their associated nerves than comparable-age mammals that do not exercise. Intense exercise is far more effective than casual exercise to:
• Prevent and treat diabetes (Circulation, July 2008; J. Applied Physiology, January 2006)
• Prevent heart attacks in obese people without weight loss (MSSE, October 2006)
• Prevent heart attacks (MSSE, July 1997)
• Reduce belly fat (MSSE, November 2008)
• Prevent premature death (Heart, May 2003)
• Prevent metabolic syndrome and heart attacks (Exercise and Sports Sciences Reviews, July 2009)
• Raise HDL cholesterol (Journal of Strength and Conditioning Research, March 2009)
(Caution: Exercise can cause heart attacks in people with blocked coronary arteries.)

Thursday, September 09, 2010

Banned Drugs Probable Cause of Athlete Deaths

If vigorous exercise is good for you, why have so many former world-class athletes died of heart attacks?

The most likely cause is previous use of anabolic steroids and human growth hormone (HGH). Doctors at the Massachusetts General Hospital found that apparently healthy, older former long- term users of anabolic steroids have weaker left ventricles, the major pumping chamber of the heart. This markedly increases their risk for heart failure and heart attacks (Circulation: Heart Failure, July 2010).

Many world class athletes in sports requiring extreme strength took anabolic steroids from the early 1960s on. When these athletes were in competition, their training made their hearts stronger than those of other people their age, and available tests failed to show any heart muscle damage. With aging, the hearts of all people weaken because they lose muscle fibers. As these former users of anabolic steroids reach middle and older age, tests can detect the heart muscle weakening that increases their risk for sudden death from heart attacks.

Taking large amounts of HGH can cause sudden death from irregular heart beats. HGH causes heart muscle to grow far more than its nerves do, and everyone loses nerves with aging. The effect of former HGH use on the hearts of older athletes has not been documented, but we do know that people who have acromegaly, a brain tumor that produces large amounts of HGH, are at increased risk for sudden death from irregular heart beats.

Sunday, September 05, 2010

How Sugar Makes You Faster and Stronger during Exercise

Just about everyone agrees that taking carbohydrates, particularly sugar, during exercise increases endurance in both humans and animals. For years, I have told everyone that eating sugar preserves stored muscle sugar called glycogen. However we have to find a new explanation because recent data show that taking sugar during exercise does not preserve muscle glycogen (Sports Medicine, September 2010). The NEW most likely explanation is that during prolonged, intense exercise, you become exhausted because you cannot keep up with your requirements for oxygen. This interferes with the sodium/potassium pumps, inside cell membranes, that pump potassium into cells and sodium out of cells.

Your brain sends electrical messages along nerves to tell your muscles to contract. When the electrical message that travels along nerves reaches its connection with muscles, other electrical messages travel along muscles to cause them to contract. The electricity comes from your cells' ability to keep sodium outside cells and potassium inside cells. This is done by "pumps" in the cell membranes.

During intense exercise, how fast you can move is limited by how long it takes to get oxygen into muscles. Anything that reduces your requirements for oxygen will help you to move faster. Sugar and other carbohydrates require less oxygen than fat and protein to supply energy to your "pumps", so sugar is a very efficient source of energy for the sodium/potassium pumps during exercise. When the sodium/potassium pumps lose their efficiency from lack of oxygen, potassium leaks from cells and you can't get enough electrical current to contract your muscles with the force you need to compete. So your muscles weaken and you have to slow down.

If you want to compete in sports that last more than 45 minutes, you will probably be faster and have greater endurance if you take in sugar while you exercise. Taking caffeine with sugar during prolonged exercise increases endurance even more. We drink sugared, caffeinated soft drinks when we race, and avoid them when we are not racing. When muscles contract, they remove sugar so rapidly from the bloodstream that you do not get a high rise in blood sugar. However when muscles are not contracting, you lose this benefit and can develop a high rise in blood sugar that can damage all of the cells in your body.

Thursday, September 02, 2010

Heavy Weights Not Needed for Muscle Growth

Exciting research from McMaster University in Hamilton, Ontario shows that you do not have to lift very heavy weights to grow large muscles (PLoS ONE. August 10, 2010).

The heaviest weight that you can lift once is called your "One Repetition Maximum" (1RM). This study questions what many non-competitive lifters do. They find their 1RM and do three sets of five repetitions at 90 percent of their 1RM.

In the Ontario study, fifteen men were assigned four sets of leg presses with one leg. They were asked to continue to extend and contract their leg muscles until they were exhausted against 30 percent of their 1RM, and against 90 percent of their 1RM. At 90 percent of their 1RM, they were usually exhausted at five to ten lifts. At 30 percent of their 1RM, they could do about 24 lifts before they were exhausted. So the lighter the weight, the more repetitions they could do. The authors used sophisticated tests for muscle growth (mixed, myofibrillar, and sarcoplasmic protein synthesis) to show that those who lifted more times at a lighter weight have greater immediate muscle growth.

This is just another case of scientists explaining and supporting training methods after athletes have used them to be successful in competition. Richard A. Winett, a professor at Virginia Tech who has published extensively on strength training, says "the stimulus from resistance training for muscle growth comes from the effort at the end of a set, where the last repetition in good form can be performed. There's no reason to use heavy resistance; moderate resistance, good form with controlled repetitions, and a longer time under tension is effective."

Dr Winett explains that for muscle growth:
• You do not have to use very heavy weights
• You should make an effort to exhaust your muscles (lift towards failure).
• Optimal growth comes from three sets to failure for each muscle and two or three exercises per muscle group.
• You should feel mild soreness on the next day. If you are very sore, you may have used too much resistance, too much volume, too large a range of motion on an exercise, too much emphasis on the eccentric part of the repetition, or you did not get enough sleep for recovery.

Do not lift weights that are so heavy that you lose form and do only partial contractions of your muscles. Try to find a workout that is not painful when you do it, but that makes your muscles feel mildly sore on the next day. As with all exercise, check with your doctor before starting a weight lifting program.