DEAR DR. DONOHUE: I am 72 years old. I walk up and down 15 flights of stairs, each flight having 17 steps. I do this once a day. Is that enough exercise for me? – J.G.

Walking up and down stairs is wonderful exercise if you spend enough time doing it and if your pace isn’t that of a snail’s. The calorie cost of climbing stairs is around 0.4 calories per step; 0.3 calories per step going up and 0.1 calories on descent. Your climb of 15 flights of 17 stairs burns 102 calories for each flight. That’s about the same as brisk walking. Brisk walking is an excellent heart exercise.

Is your stair climbing enough exercise? It is if you spend 30 minutes doing it. The 30 minutes doesn’t have to be one session. It can be two 15-minute sessions or three 10-minute ones. I don’t want to kid you. All of what I say is very imprecise. I need your body weight to give you a better estimate.

Don’t try to reach the 30 minutes of exercise right away. Increase the time you spend on the stairs by about three additional minutes a week until you are at the 30-minute goal. You can make smaller weekly increments if you want.

I have to issue the usual warnings. Clear all exercise with your doctor.

There’s another warning I have to give you. Stair climbing is harder on your knees and hips than is walking on a level surface.

Let’s forget the calorie business. You can judge if your exercise is sufficient by taking your pulse. At your age, your pulse should reach 103 beats a minute during the exercise, and it should stay at that rate for 10 minutes if you’re dividing your exercise time into three sessions of 10 minutes.

The booklet on aerobic exercise explains how to benefit your heart in clear language. Readers can order a copy by writing: Dr. Donohue – No. 1301, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: I am an amateur boxer with hopes of going pro. When I began boxing, I weighed 326 pounds. Currently I am 230 pounds. I would like to take the next step and weigh in at 175 pounds. During off time I occasionally have weight-loss challenges with my friends. I am going to begin another competition with them. I have heard that, since I spend a lot of free time sleeping, my thyroid is being overworked because of the extreme weight gains and weight losses. Does this fluctuation in weight have any health effect? – I.M.

Yo-yo dieting (weight loss followed by weight gain) can affect health. It often lowers HDL cholesterol – good cholesterol, the kind of cholesterol that prevents heart attacks and strokes. The only way to find out if this is happening is to have your HDL cholesterol checked.

Rapid weight loss involves losing muscle protein – muscle mass. A weight loss of 1 or 2 pounds a week minimizes such protein loss. Combining dieting with exercise also minimizes protein loss.

I am not aware of any health effects on the thyroid due to dieting.

DEAR DR. DONOHUE: My 17-year-old son is a baseball pitcher. Last week he came home with his pitching arm greatly swollen. I was alarmed, and I told my husband we needed to take the boy to the emergency room. My husband thought I was overreacting, but I insisted. I am glad I did. He had a blood clot in a vein that caused the swelling. They treated him with medicine to dissolve the clot and put him on a blood thinner. Will he ever pitch again? – R.C.

I’m sure the ER doctors checked your son for things that make a person prone to form clots. He must not have had any of those conditions. He had an “effort-induced” clot, a clot caused by repetitive physical exertion. Now that the clot has been dissolved, you son should be able to resume pitching after the rest period prescribed by his doctor.

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

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