DEAR DR. DONOHUE: I have arthritis in both knees. I’d exercise, but I’m afraid of making the knees worse than they are now. My neighbor is into water exercise, and she says it would be the perfect exercise for me. Do you agree? – B.W.

Water exercises are excellent for people with arthritic hips and knees – and also for people without arthritis. Water buoyancy removes stresses on the knees and hips.

People get the most joint protection from water that is chest-high.

I’m sure water aerobics are at least part of the exercise period. Aerobic exercise is the kind of exercise that benefits the heart and lowers blood pressure. Large muscles, like leg muscles, are kept in constant motion to raise the heartbeat and keep it elevated for 20, 30 or more minutes. I know you won’t start at that level. You’ll do the same kinds of motions you’d do on land but, in most classes, the exercisers stay in place.

You also can do resistance exercise in water. Resistance exercise is muscle-building and -strengthening exercise. An example of resistance water exercise for the arms and shoulders makes use of a floatation device called a noodle. It looks more like a drainpipe than a noodle. It’s held at waist level under the water and then raised through the water to above the head. Water resists your lifting the device and makes this equivalent to lifting a weight on land.

Sure, enroll in a class. People need instructions in the proper way to exercise in water. Once you’ve learned the techniques, you can exercise on your own.

DEAR DR. DONOHUE: What is the recommended water temperature for seniors to exercise in? I rely on exercise in the pool to keep me healthy. Three mornings a week we spend a solid hour in water exercise. The spa whose pool we use has lowered the water temperature so that it is uncomfortable for many of us, and some have had to drop out. – N.M.

The suggested water temperature for swimming is 83 to 86 degrees F. That range is cool enough to prevent swimmers from overheating but warm enough to keep them from freezing.

Some recommend an even higher range, up to 92 F (33 C).

Can’t your fellow exercisers remind management that you are the ones paying the bills?

DEAR DR. DONOHUE: I read your article on treating a sprain with RICE. I have a better recipe.

Last August, while jogging down a mountain trail, I sprained my left ankle. I put an ankle bandage on and walked three miles to my car. Due to a previous sprain, I had given up hiking for six months. Here I was, scheduled to lead the first group of hikers on a new trail on one of the highest mountains in the Catskills. That was scheduled for seven days hence.

I had read of a way to treat a sprain with exercise. The next day I soaked my ankle in hot water for 15 minutes to anesthetize it. Then I did up-and-down movement with my left foot. I then walked half a mile without any wrap on the ankle. I repeated this daily for the next week. I was able to lead the 11-mile hike. – F.C.

ANSWER: I appreciate your story and I admire your fortitude, but you haven’t convinced me that this is safe treatment for the general public, and I include myself as a member of the general public.

RICE is Rest, Ice, Compression and Elevation. A sprain indicates ligaments have been torn. Rest is essential for healing. Ice in the first 48 hours lessens swelling and helps stop bleeding. Compression means using something like an ACE wrap. It, too, limits swelling, as does elevation, the E of rice.

I’ll keep you in mind the next time I sprain my ankle, but I’m sticking with the RICE program.

DEAR DR. DONOHUE: My daily exercise includes a stationary bike. I am concerned that attaining the peak heart rate for my age could be detrimental to my health. I used the standard formula to compute maximum heart rate: 220 minus age. For me, age 65, that’s a rate of 155. Should I be limiting my peak heart rate during exercise? – S.P.

The formula you use is a standard formula for estimating maximum heart rate. People are told to take 65 percent to 85 percent of their maximum heart rate to get their heart beating in a zone that provides adequate but safe heart exercise. For you that would be an exercising heart rate between 100 and 132.

This rule is not a federal law and is not based on great scientific evidence. The estimate has a variance of plus or minus 15 beats.

Getting your heart beating at the maximum of 155 beats a minute takes quite strenuous exercise. Most people cannot exercise for very long when their heart beats at the maximum.

How do you feel during exercise? Are you dizzy? Does the exercise exhaust you? Do you have any chest pain? Are you gasping for breath? If you answer yes to any of these questions, your heart rate is too high. If you answer no, it might not be.

The only way to tell you with absolute certainty that your exercise isn’t harming you is for you to have a stress test. During the test, you raise your heart rate to high levels. An EKG is continuously running during the test, and signs that the heart isn’t getting enough blood can be seen by changes in the EKG. Talk to your doctor about this.

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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