DEAR DR. DONOHUE: Is there any benefit in warming up before playing a sport? I play tennis. In the winter, that means indoor tennis, and the building is on the cool side. I wonder if warming up before playing improves a person’s game. I heard it does. Is that dreaming? – D.B.

No, it’s for real.

The benefits of warming up are many. Warm-ups, as the name implies, increase body temperature. That, in turn, increases circulation and provides heat to muscles and tendons. Warm muscles and tendons react faster and contract more forcefully. The warmth makes them more elastic, and that might prevent injuries, although this hasn’t been proven. Warmth enhances joints’ range of motion. The boost in blood flow takes away the waste products of exercise, one of which is lactic acid. Lactic acid tires muscles and leads them to work with less and less vigor.

Warm-ups are not the same as stretches. They’re exercises that require nonstop movement without interruption. Running in place, jogging at a reduced speed, continuous sit-ups with taking only a short pause when the muscles tire, and calisthenics are examples of warm-ups.

Some people – many tennis players – sit in the sauna or steam room before playing. They feel that’s equivalent to warming up. It is, but it’s not a great way to do so. It’s passive warming up, and that doesn’t accomplish as much as actively warming up does.

DEAR DR. DONOHUE: I am 57 and a housewife. I get very little physical exercise other than the housework I do. Does exercise really make one healthier, and does it really prolong life? If you say it does, I’ll start exercising. If you say it doesn’t, I’ll be relieved and remain a sloth. – J.A.

Exercise really does make people healthier and really does prolong life. You didn’t think I would answer differently, did you? You are a truthful person. Most people overestimate the amount of exercise they do and underestimate the number of calories they eat.

If a person can manage to burn, through exercise, 287 or more calories a day, the risk of death at a younger age than the predicted age of death decreases by 30 percent.

How much work is 287 calories? As far as housework goes, one full hour of vacuuming burns 160 calories; mopping, 250; and window washing, 250. People don’t window-wash or mop every day. Vacuuming rarely takes a full hour.

If you can get in a walk, you could reach the 280-calorie goal without a lot of fuss. Walking at the rate of 2.5 miles an hour burns 200 calories in one hour. That’s not a fast rate. Almost everyone can walk at that pace. You don’t have to do the entire hour in one session. You can break your walks into 10-, 15- or 20-minute periods.

If you can walk faster, you will, of course, burn more calories.

DEAR DR. DONOHUE: I am preparing myself for spring golf by lifting weights. Will weightlifting add any distance to my drives? – B.J.

Weightlifting isn’t going to add much yardage to your drives, but it will do a whole lot for you in general. You’ll have stronger muscles. Your bones will be stronger. You’ll be able to keep your weight in check, something many Northerners aren’t able to do in the winter.

Strong shoulder, arm, abdominal and leg muscles increase the acceleration of your swing, and that imparts greater distance to the ball, but the strength required isn’t great strength.

Of more benefit to your golf game is exercising your arm, shoulder, abdominal and leg muscles in the same way they are used when you swing a golf club. You can do that by repeating the swing as an exercise. That kind of exercise is sport-specific exercise. You’re using the muscles involved in your sport in the exact same way you use them when playing the sport.

DEAR DR. DONOHUE: I am in ninth grade. My high-school biology teacher, Mrs. Schack, has us read your articles every Sunday, and we have a quiz on Monday. The quiz is mostly on hard words like the ones I have underlined in one of your articles. Would you explain more of the medical words for us? – K.D.

DEAR DR. DONOHUE: How are you? I want to let you know that every Monday my biology classmates and I have a vocabulary quiz on words from your column. You are a major part of our Sundays. Classmates call one another and ask: “Did you do your Dr. Donohue yet?” Thank you for doing what you do. – M.

Thanks, K.D. and M., for writing. I’ll make explanations of medical words on Sundays a special priority.

Mrs. Schack must be a woman of extraordinary talent and insight to have her students read this column. She has become my best friend.

Write again. I’d like to know how you’re doing.

I have an assignment for you: How about changing the size of the scabies mite from millimeters to inches?

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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