Monday, November 27, 2006

Creatine: Will it prevent muscle loss with aging?

Each muscle has millions of muscle fibers, and each muscle fiber is enervated by a single nerve. With aging, you lose nerves and with loss of each motor nerve, you lose the corresponding muscle fiber. So the treatment of muscle weakness with aging is to increase the size and strength of each remaining active muscle fibers. You do this only by exercising against increasing resistance.

Creatine will do nothing to stop the progressive loss of nerves that decreases the number of active muscle fibers. However, it can help you to exercise harder and longer, so it may help you to do the intense workouts that will build larger and stronger muscles. At this time we do not know whether there are any deleterious side effects in older people from taking creatine, so I cannot recommend it.

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Creatine can help to strengthen muscles, but athletes who take these supplements need to know how much they can take safely before they harm themselves. When you exercise and your muscles get as much oxygen as they need, they burn carbohydrates, fats and protein for energy. When you exercise so intensely that you cannot get all the oxygen you need, your muscles use creatine and ATP. So when you exercise so intensely that you can't get enough oxygen, you can delay fatigue by taking creatine and it allows you to do more work, which makes you stronger.

The body of a 160 pound man contains 120 grams of creatine and he takes in and uses about two grams a day. No good studies have been done to show what amounts are safe to take beyond what your own body makes, so let the buyer beware. Creatine may allow you to lift more weights and make you stronger, but it may harm you. Taking too much creatine can cause weight gain, increased insulin production and possibly kidney damage. High levels of insulin constrict arteries to cause heart attacks and affect the brain and liver to make you fat. The chemical process of extracting creatine in the laboratory forms toxic contaminants called dicyandiamide and dihydrotriazines, that have to be removed before humans can take them safely. The industry that distributes creatine is unregulated and you have no way to know what you are actually buying.

Wednesday, November 22, 2006

Cold hands

If your fingers turn white and start to hurt when you're out in the cold, you may have a condition called Raynaud's phenomenon. On exposing your fingers to cold, the blood vessels close, skin turns white and their temperature drops. When the temperature drops to 59 degrees, your body tries to save your skin by opening the blood vessels and the skin turns red and starts to itch and burn. If you warm your hands at this point, your skin will not be damaged, but if you do not get out of the cold, the blood vessels in your hands can close and the temperature in your hands can drop to freezing, resulting in frostbite.

People who have Raynaud's phenomenon have blood vessels in their hands that do not open when the skin temperature reaches 59 degrees. Several diseases, smoking and using vibrating equipment can cause Raynaud's phenomenon.

Wear two or more layers of gloves and mittens. When your fingers feel cold, swing your arms very rapidly about your shoulder with your elbow straight. This will drive blood, like a centrifuge, into your fingers and warm them. The blood pressure drugs called calcium channel blockers, such as Nifidipine, can help to treat and prevent Raynaud’s phenomenon (Rheumatology, November 2005). Another option is nitroglycerin ointment that is used to treat angina. When applied to the forearm, it opens blood vessels leading to the hands. Check with your doctor to see if these prescription medications would be appropriate for you.

Tuesday, November 21, 2006

Master athletes age better

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 (Nutrition Today, Volume 40, 2006). 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.

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Sunday, November 19, 2006

Why do athletes use asthma inhalers?

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.

Saturday, November 18, 2006

Exercise prevents diabetes

A recent study shows that lack of exercise is a major risk factor for diabetes in overweight women, and these women can help prevent diabetes by exercising, even if they don’t lose a lot of weight. Before insulin can do its job of driving sugar from your bloodstream into cells, it must first attach to small hooks on cells called insulin receptors. Having extra fat in your body prevents insulin from attaching to these receptors, and prevents insulin from lowering blood sugar levels. Therefore the cells of overweight women cannot respond to insulin as well as those of their leaner counterparts. Researchers at the University of Massachusetts in Amherst showed that overweight women who engage in vigorous exercise can respond to insulin as well as leaner fit women (Medicine and Science in Sports and Exercise, October 2006). Thirty-five percent of North Americans will become diabetic, and staying in shape may be an even better way to prevent diabetes than controlling weight.

Tuesday, November 14, 2006

Caffeine increases endurance

Caffeinated drinks increase endurance during long events such as a marathon, triathalon or bicycle race. A study from the University of Birmingham in England shows that caffeine helps the body use more carbohydrates from drinks that you take during exercise (Journal of Applied Physiology, June 2006). Those who took sugared drinks with caffeine were able to absorb and use 26 percent more of the ingested sugar than those who took the same drinks without caffeine.

Previous studies show that caffeine helps athletes run faster in both short and long-distance races. In short races, it makes athletes faster by causing the brain to send messages along nerves to cause a greater percentage of muscle fibers to contract at the same time. In longer races, it delays fatigue by preserving stored muscle sugar. Muscles get their energy from sugar and fat in the bloodstream, and from sugar, fat and protein stored in the muscles. When muscles run out of their stored sugar, they hurt and become more difficult to coordinate. Caffeine causes muscles to burn more fat, thus sparing stored muscle sugar to delay fatigue.

Nobody really knows how much caffeine you can take in without harming yourself. At rest, caffeine is a diuretic, but during exercise it does not increase urination. Caffeine is a potent stimulant that can cause irregular heartbeats in people who already have heart disease, and raise blood pressure in people with hypertension. Most research shows that it doesn't take much more than one or two soft drinks to increase endurance. Caffeine loses its beneficial effects with repeated exposure, so athletes who want to gain maximum advantage from caffeine during competition should avoid drinking caffeinated beverages when they are not exercising.

Monday, November 13, 2006

Lactic acid is good for you

Lactic acid is the most efficient fuel that your muscles can use, even more than sugar. When you exercise as hard as you can, it helps you to go harder. A paper from Aukland University in New Zealand reviews the latest research showing that lactic acid is good for you (Sports Medicine, Volume 36, 2006). Your muscles use carbohydrates, fats and proteins for energy. Enzymes in muscles break down carbohydrates in a series of reactions that release small amounts of energy at a time. More than 80 percent of the energy used to power muscles is lost as heat, so burning fuel instantly for energy would produce so much heat that it would burn your muscles.

Enzymes require oxygen to turn food into energy. When you exercise so hard that you can’t get all the oxygen you need to break down food for energy, lactic acid accumulates in muscles and spills over into the bloodstream. This makes muscles acidic and it is the acidity that makes muscles burn and forces you to slow down. However, muscles require very little oxygen to turn lactic acid into energy. So when your muscles produce lots of lactic acid, they use this chemical for energy and require less oxygen. As soon as you slow down, you catch up on your oxygen debt and recover. So lactic acid is good for you. It helps you to exercise with less available oxygen.

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Sunday, November 12, 2006

Cold hands

If your fingers turn white and start to hurt when you're out in the cold, you may have a condition called Raynaud's phenomenon. On exposing your fingers to cold, the blood vessels close, skin turns white and their temperature drops. When the temperature drops to 59 degrees, your body tries to save your skin by opening the blood vessels and the skin turns red and starts to itch and burn. If you warm your hands at this point, your skin will not be damaged, but if you do not get out of the cold, the blood vessels in your hands can close and the temperature in your hands can drop to freezing, resulting in frostbite.

People who have Raynaud's phenomenon have blood vessels in their hands that do not open when the skin temperature reaches 59 degrees. Several diseases, smoking and using vibrating equipment can cause Raynaud's phenomenon.

Wear two or more layers of gloves and mittens. When your fingers feel cold, swing your arms very rapidly about your shoulder with your elbow straight. This will drive blood, like a centrifuge, into your fingers and warm them. The blood pressure drugs called calcium channel blockers, such as Nifidipine, can help to treat and prevent Raynaud’s phenomenon (Rheumatology, November 2005). Another option is nitroglycerin ointment that is used to treat angina. When applied to the forearm, it opens blood vessels leading to the hands. Check with your doctor to see if these prescription medications would be appropriate for you.

Friday, November 10, 2006

Awkward running form

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.

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Wednesday, November 08, 2006

Weight lifting for children

The best time for future Olympic athletes to start training is before they reach puberty. Having large strong muscles makes you a better athlete, and starting training before puberty enlarges the bones that are used primarily in that sport. Muscles growth is limited by the size of the bones on which they attach. The larger the bone, the stronger the muscle. Children who start to play tennis before they go into puberty have larger bones in the arm that holds the racquet. They also have larger bones in their tennis arm than those who start to play tennis later in life. The larger and stronger your muscles, the harder you can hit a tennis ball.

Lifting weights during growth does not prevent children from growing to their full potential height. Bones grow from growth centers that are weakest part of bone, but strength training during growth does not damage these growth centers and children who lift weights in programs with experienced supervision do not suffer more injuries than adults. There used to be concern that growing large muscles would make people musclebound and interfere with coordination, but this is not true. With increased strength comes increased speed and increased coordination in movements requiring strength. The best time for future Olympians to start training is while their bones are still growing.

Tuesday, November 07, 2006

Are you pre-diabetic?

You can tell if you are at high risk for diabetes if you store fat primarily in your belly. Pinch your belly; if you can pinch an inch, you are at increased risk and should get a blood test called HBA1C. Having high blood levels of triglycerides and low levels of the good HDL cholesterol that helps prevent heart attacks also increases your risk for diabetes. When you eat sugar or flour, your blood sugar rises too high. This causes your pancreas to release insulin that converts sugar to triglycerides, which are poured into your bloodstream. Then the good HDL cholesterol tries to remove triglycerides by carrying them back into the liver, so having high blood levels of triglycerides and low blood levels of the good HDL cholesterol are both individual risk factors for diabetes.

High blood levels of insulin constrict arteries to raise blood pressure, so many people who have high blood pressure are also prediabetic. High insulin levels also constrict the arteries leading to your heart to cause heart attacks directly. People with insulin resistance have an increase in small, dense, low-density lipoprotein (LDL) cholesterol, which is more likely to cause heart attacks than the large, buoyant regular LDL cholesterol. High levels of insulin also cause clotting to increase your risk for heart attacks. You can help to prevent diabetes and heart attacks by avoiding sugar and flour, exercising and eating lots of vegetables.

More on treatment of insulin resistance

Friday, November 03, 2006

No weight loss from exercise?

When people start an exercise program, some lose a lot of weight, while others lose nothing. An effective exercise program for weight loss should be 1) continuous, 2) use all of your major muscle groups, 3) include one intense workout a week for each muscle group, and 4) be done on land, rather than in the water. Stop-and-start exercises, such as lifting weights, do not require that you use your muscles continuously enough to burn a lot of calories. Those that use just one muscle group, such as doing situps or pushups, won't help you to lose a lot of weight because the stressed muscle groups tire quickly so you can't exercise very long.

Exercising at a leisurely pace won't help you lose a lot of weight either. You burn calories while you exercise and after you finish exercising. Intense exercise raises body temperature which continues to be elevated and burn more calories for several hours after you finish exercising. This also explains why swimming is not the best exercise for weight loss, because water conducts heat away from your body so fast that your temperature does not rise. When you exercise on land, air insulates your body so your temperature rises.

Pick sports in which you can exercise intensely, but don't exercise very hard in one sport more often than once a week. Every time that you exercise, your muscle fibers are torn slightly. You can tell this has happened to you when you muscles feel sore on the day after you have exercised. If you exercise intensely on days when your muscles feel sore, you are at increased risk for injuring them. Instead, alternate two sports, one that stresses your upper body and one that stresses your lower body. And (of course) don't forget healthful eating habits.

Wednesday, November 01, 2006

Urinary tract infections: treat with antibiotics

Many men suffer from constant irritation in their urinary tubes, urinating frequently at night, urgency to urinate when their bladders fill, and discomfort during urination. Often doctors do a culture which shows no cause, so they prescribe doxycycline antibiotics for a week or two, and their patients get no relief. A study from Karolinska University Hospital in Sweden shows that many of these patients are infected with a bacteria called mycoplasma genitalium which cannot be cured by taking doxycycline, but can be cured by taking an erythromycin antibiotic such as Zithromax, or Biaxin (Sexually Transmitted Infections, August 2006).

If you are a man or woman who suffers persistent urinary symptoms, check with your doctor and ask for a urine culture for mycoplasma or just an extended prescription for an erythromycin-type antibiotic.

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