DEAR DR. DONOHUE: I am a 70-year-old man in good condition. My blood pressure is 118 over 75, and my resting heart rate is 66.
I have been working out at the gym for several months. The past two weeks, I’ve been pushing myself. I do 45 minutes of weightlifting with little rest between exercises, and then I run on a treadmill for 30 minutes. I am concerned about my heart rate. After my weight workout, my heart rate is between 90 and 100. After 20 minutes of running, I reach 85 percent of my maximum heart rate, 127 beats a minute. I’m not tired or winded, so I have been pushing to 135 and even went as high as 142. I got scared and cranked down. I had an echocardiogram, which was good. Should I be concerned about my heart rate? – F.P.
Focusing on heart rate often worries people more than it should. For heart benefit, the heart has to beat fast and maintain the faster beat for at least 10 minutes. How much faster? One rule, used for many years, is a simple one. Deduct your age from 220 and you have an estimate of your maximum heart rate. For you, the maximum rate is 150 (220 — 70). Maximum heart rate is the fastest your heart can beat. Next comes determining your training zone. Sixty percent of the maximum rate sets the lower limit of the training zone, which is 90 for you. (150 times .6 equals 90). Eighty—five percent sets the upper limit — 127 for you. (150 times .85 equals 127).
This rule is not a golden rule. It’s a guess. For a well—conditioned person with a somewhat—slow resting heart rate, it sets the upper limit too low, and for the poorly conditioned, it sets the lower limit too high. The only exact way to determine a safe heart rate is having an exercise stress test. Everyone over 45 should speak to the doctor about exercise intensity, and sometimes the doctor will suggest a stress test.
Perceived exertion is another way to determine the safety and effectiveness of exercise. It judges exercise intensity by the way a person feels. If exercise doesn’t leave people panting for air, doesn’t make them dizzy and doesn’t produce chest pain, you can be fairly sure that level of exercise is safe.
DEAR DR. DONOHUE: I’d like some information on swimmer’s ear. For the past six months I have had fluid behind my ears. It happens in one or both ears. I have tried various medications, but nothing seems to help. I would appreciate your suggestions. — W.S.
Swimmer’s ear comes from water remaining in the ear canal. Swimming isn’t the only activity that produces it. Taking a shower can leave water in the canal. A wet canal denudes it of its protective coat of wax and promotes the growth of bacteria and fungi.
A mixture of equal parts of white vinegar and rubbing alcohol dries and sterilizes the canal. One or two drops of the mixture left in the canal for two or three minutes and administered three times a day can usually put an end to the problem. After each instillation, bend the head to the side to drain the mixture.
But, hold it there, W.S. You don’t sound to me like you have swimmer’s ear. Ear pain or itching or both are the hallmarks of swimmer’s ear. I’m not sure what you mean by “fluid behind the ears.” You have to see the family doctor to determine exactly what you have before any treatment can be given.
DEAR DR. DONOHUE: I am a large—breasted woman who loves horseback riding. I am going to give it up because my breasts are so sore after a ride. Any ideas of what I can do? — L.O.
A sports bra would help. You can find them in many stores. The best kind for a large—breasted woman is one with separate cups. That sort of design is referred to as encapsulation. The bra should either be seamless or have covered seams.
If you have access to a computer, go online at for some ideas.
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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