DEAR DR. DONOHUE: You give exercise advice for athletes. What about exercise for someone with arthritis? I have arthritis, and right now, my knee is bothering me. I had to quit using an elliptical machine, but I can use the bike. How much motion should the knee have when it is hurting? – E.M.

DEAR DR. DONOHUE: What kinds of exercises are good for people with arthritis? – B.D.

If an exercise hurts a joint, stop it. A different exercise can be tried, but pain means the exercise is not helping – it’s harming. “No pain, no gain” is one of the most inane sayings ever mouthed.

People with osteoarthritis, the most common kind of arthritis, are encouraged to exercise. They should do both the kind that benefits the cardiovascular system (heart and arteries) – aerobic exercise – and the kind that strengthens muscles.

Biking (both outside and on a stationary bike), walking, dancing and swimming are aerobic exercises that people with arthritis can do. Such activities don’t jar joints. Water aerobics are particularly good because the water’s buoyancy cushions joints. Almost all YMCA’s feature such exercises.

Strength training is equally important. Strong muscles protect joints and improve their range of motion. If a person has never lifted a weight, that person should begin with isometric exercise, the kind in which muscles tense but nothing moves. Examples of isometrics are pushing with the hands against a heavy desk or doing the same against a wall, or pushing, while seated, the feet against the floor. After two weeks of isometric exercises, a person can begin lifting weights. Start with modest amounts, such as 2 pounds. If that’s too much, use 1-pound weights. When a person can do two sets of 10 repetitions with a weight, the amount of weight can be increased, and then the person begins anew with fewer repetitions.

Exercise doesn’t hurt joints. It greatly helps them.

DEAR DR. DONOHUE: I am 72, 5 feet 6 inches tall and weigh 135 pounds. I have been retired from construction for 12 years and had an amputation six years ago. Since then, I have lost 15 pounds.

About a year ago, I joined a gym and started working on weight training. I’m getting stronger, but not gaining weight or muscle size. Can you suggest a way for me to get more definition to my upper torso? – R.E.

At 72, you can’t expect to gain the muscle size that a young man at age 20 can gain through weight training. In large part, that’s due to a diminution of the amount of testosterone – the male hormone – that’s made in older age.

You can definitely gain muscle strength, as you have proved to yourself. And you can make some progress in muscle size if you stick with it, but you must increase your calorie intake. Get a paperback book with the calorie content of foods. For a full week, keep track of what you eat every day and add up each day’s calories. Then average them for a week. When you obtain the average, add 500 more calories to your diet every day. You should gain a pound a week, and much of that gain will be muscle if you keep on exercising. Just don’t expect unrealistic gains.

DEAR DR. DONOHUE: I am 91, and I work out for two hours, six days a week. I work hard and can push up to 200 pounds with my legs.

My concern is: Is there an age when exercise will do more harm than good? – J.R.

That’s everyone’s concern. And it’s the reason why older people are told to visit their doctor before beginning an exercise program. Limits can be set only with an exam and often with some tests, like a stress test.

Birthday age and true physical age are not always the same. Your exercise program is extraordinary. It’s apparently not doing you any harm, and it must be doing you a world of good. Signs that you have reached a danger zone would be things like chest pain while exercising or such a degree of breathlessness that it feels like you are on the verge of passing out.

I would like to give you general rules, but none exists. Have your doctor do this for you.

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

Only subscribers are eligible to post comments. Please subscribe or to participate in the conversation. Here’s why.

Use the form below to reset your password. When you've submitted your account email, we will send an email with a reset code.