DEAR DR. DONOHUE: Do some people sweat more than others? If they do, I’m one of them. I jog on a treadmill for half an hour at a speed that is not all that fast. When I’m through, I am dripping in sweat. Those around me, running a lot faster than I do, are dry. Is this much sweating bad for me? I feel OK. — R.M.

ANSWER: Sweat has purpose. Its evaporation from the skin cools the body. When a person is drenched with sweat, the temperature, the humidity or both are quite high or the person is an excessive sweater. Some people are.

It’s possible to decrease sweating through medicines, but you don’t want to do that. Only in exceptional circumstances would that be considered. Yours is not an exceptional circumstance.

You do, however, have to estimate how much water your body loses from sweating. Weigh yourself before exercise and again after. The weight loss is water loss. People believe they have lost fat when there’s a big change in weight after exercise. They haven; they’ve lost water.

For every pound lost, you should replenish with a pint of water. (For every kilo lost, replace with a liter of water.)

Before you exercise, hydrate yourself by drinking two 8-ounce glasses of water three hours before and again one hour before.

Only for an extended exercise session when weight loss is profound — 3 percent to 5 percent loss of body weight — do you need to replace the loss with fluid that has some salt in it or to drink one of the many sports drinks that contain salt.

DEAR DR. DONOHUE: My body is rebelling against my running. I have run consistently for many years and have had no problems. Now I am getting soft and frequent stools on the days I run. It’s not diarrhea, but it’s not normal. Is it due to running? — A.K.

ANSWER: It could be. Long-distance running can upset the digestive tract. The leg muscles are demanding more blood, and they get it by diverting the digestive tract’s blood supply.

One-third of marathon runners have experienced diarrhea and stomach cramps. It has a name — runners’ trots.

Take a week rest. Restart your program by running shorter distances. Only gradually increase them — 10 percent per week.

DEAR DR. DONOHUE: I started a weightlifting exercise program this year and have been faithful to it. The first three months I made great gains rapidly. From that point on, my progress has been zero. What’s gone wrong? — D.G.

ANSWER: Rapid progress is standard in the beginning, not because muscles have gotten so much stronger, but because the brain has activated pathways to the muscles that it hadn’t used in the past. Once those pathways are established, progress is much slower, all but imperceptible.

Introduce some change to your program. Muscles grow only by giving them new challenges. A simple way is to decrease the weight you’re lifting and increase the repetitions or decrease the number of repetitions, and increase the weight. An easy change is the way you grip the barbell or dumbbell. Or you can change your exercises; do completely different ones.

Everyone reaches a plateau where progress slows. New approaches can get you off such a plateau.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.

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