Body mass index revisted


DEAR DR. DONOHUE: I lost my body mass index chart. My druggist told me to use the Internet to get another.

One problem: I’m a senior citizen with no computer. Will you be so kind as to send me a chart with the body mass index? — J.L.

ANSWER: I don’t have body mass index charts. However, I can give you a quick and easy way to compute your BMI.

Step 1: Multiply your weight by 703. Step 2: Multiply your height in inches by itself. Step 3: Divide the number you obtained in Step 1 by the number you got in Step 2. That’s your BMI.


Let’s say you weigh 130 pounds. Multiply 130 by 703. The result is 91,390.

I’ll make you 5 feet 4 inches tall. You sound like you’re that height. That’s 64 inches. Multiply 64 by 64 to get 4,096.

Now divide 91,390 by 4,096, and you get a body mass index of 22.3

A body mass index of 18.5 to 24.9 is normal; 25 to 29.9 is overweight; 30 and above is obesity.

A hand-held calculator, not an expensive item, makes the arithmetic much easier.

Canadians, used to the metric system, obtain body mass index by dividing weight in kilograms by height in meters squared.

All this sounds very mysterious; it isn’t. It provides a better estimate of what your body weight is composed of — muscle and bone versus fat. It’s far from a perfect measurement, but it beats weight taken on a scale.

DEAR DR. PHIL: I am a 42-year-old male who doesn’t drink and never smoked.

Here’s the problem. I recently started to work out. At the least little workout, I become short-winded. I mean I can’t run for a full three minutes. I have a workout partner who smokes and has smoked for 30 years. He can run a full 40 to 50 minutes. Why do I become short-winded so soon? — S.W.

ANSWER: I believe the answer is you are out of condition. Your smoking friend has been running much longer. And a second reason could be your running speed. How fast are you running? Are you sprinting? No one can run at all-out speeds for any length of time. World-class time for the 100 meter (109 yards) sprint is 9.58 seconds. Anyone who runs at that speed cannot run more than a few more steps.

Start a running program at a pace where you can carry on a normal conversation. The might be an easy jog or a slightly brisk walk. Increase the distance you run and the speed at which you run by 10 percent every week. Soon you will be up to your partner’s pace.

Because I’m not sure about all this, see your doctor to be certain you don’t have a heart or lung problem.

And my name is Paul, not Phil.

DEAR DR. DONOHUE: As a teenager in the 1940s, after gym class all the students had to step into a foot bath before showering. After showering, we had to step in the foot bath again. This was probably the best way to control athlete’s foot. What hasn’t this practice been continued? — A

ANSWER: I remember those foot baths. They were at every public swimming pool. I’ll bet they were discontinued because someone finally determined they were doing more to spread athlete’s foot than to prevent it.

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