The burning you feel in muscles during intense exercise is different from the burning and pain you feel after exercising. Burning during intense exercise is caused by the acidity from accumulation of lactic acid. When your muscles cannot get all the oxygen they need to convert food to energy during intense exercise, lactic acid accumulates in muscles, makes them more acidic, and the acidity causes a burning feeling. Excess lactic acid is cleared from the muscles within seconds after stopping exercise.

Lactic acid is good because it is the most efficient fuel for muscles during exercise. It requires less oxygen for energy than virtually all other fuels. Sodium bicarbonate (baking soda) neutralize lactic acid in muscles during intense exercise and helps athletes to exercise longer (Medicine & Science in Sports & Exercise, October 2006). Caffeine (the amount in four cups of coffee) reduces muscle burning during intense exercise (International Journal of Sport Nutrition and Exercise Metabolism, April 2009). More on lactic acid

Burning or pain eight to 24 hours after exercising is usually caused by damage to the muscles themselves. The longer you stay in the burn during exercise and the greater the force on your muscles during exercise, the greater the muscle damage. Most athletes train by taking a hard workout on one day, damaging their muscles and feeling sore on the next, and then going at low intensity for as many days as it takes for the soreness to disappear. When muscles heal from hard force on them, they become stronger. Athletes recover from hard exercise actively by exercising at low intensity. They rarely take days off. Exercising at low intensity during recovery makes muscles more fibrous which protects them from injury when they are stressed again.


Reports from

Comfortable exercise bikes
Gall bladder pain
Swollen testicles


Dear Dr Mirkin: My doctor told me that my irregular heart beats won’t harm me. Should I continue to enter bicycle races at age 65?

Nobody knows. Exercise cannot hurt a healthy heart. However, some heart problems are silent and a person may not know that he has a problem. This is a very controversial subject. We know that master athletes have a very high incidence of irregular heartbeats, such as intermittent atrial fibrillation (Annals of Internal Medicine, April 2009). Many doctors put these people on anticoagulants but we do not know if this is necessary for them. You probably have a harmless irregular heartbeat that should not keep you from competition. However, it is always possible that you may have hidden heart problems.

Personally I still compete at age 75, take no medication, and do not restrict myself. When I started to compete again after many years of less regular exercise, I would suddenly lose my breath, which can be a sign of irregular heartbeats. By the time I recovered my breath, I would be so far behind that I could not catch anyone. I may have taken great risks, but now that I am riding regularly and following a good training program, it does not happen anymore.


Dear Dr. Mirkin: Do professional football players have high risk for diabetes or heart attacks?

A study of active National Football League players shows that even though they are very heavy, they have lower fasting blood sugar levels than the average American (JAMA, June 1, 2009). This agrees with other studies that show that exercise helps to prevent diabetes. Exercising muscles draw sugar from the blood stream to help prevent diabetes.

Despite their huge intake of calories, they did not have higher total cholesterol or the bad LDL cholesterol. However, those who were overfat had higher blood levels of the bad LDL cholesterol, triglycerides, and fasting sugar, and lower levels of the good HDL cholesterol. Full fat cells produce hormones that promote inflammation which increases heart attack risk.

The NFL players were more likely to suffer from high blood pressure. This could be a false finding since they have very large arms which require more pressure to shut off blood flow when blood pressure is measured.


Recipe of the Week:

Caesar Salad with Tofu Dressing

You’ll find lots of recipes and helpful tips in The Good Food Book – it’s FREE