DEAR DR. DONOHUE: I am a 23-year-old woman who took up running about three years ago. I am very devoted to it. I have just recently increased my mileage to more than six miles a day. I am on the slender side and watch what I eat, but I think I eat a balanced diet. I have not had a menstrual period since I increased my running mileage. Could that have caused my periods to stop? — V.P.

ANSWER: Your increased running program might be the reason why your periods have stopped. Dedicated female athletes can develop the so-called female triad, a syndrome with three symptoms. One is menstrual irregularity. Menstrual periods can diminish in number or stop altogether. The second member of the triad is an eating disorder. That’s “disorder” in a very broad sense. It often means that the female athlete is not consuming enough calories to support her level of activity. The third part of the triad is a loss of calcium from bones, something that the woman is not aware of unless it is specifically looked for by the doctor.

Women need a certain amount of body fat and calories to sustain estrogen production. When there is a drop in estrogen levels, menstrual periods either diminish or stop.

Cut back on your exercise and increase your food intake. If you have the female triad, doing these things should get your periods started again.

It is best for you to see a doctor. There are many serious conditions that cause a loss of periods. The female triad is only one of them. The matter must be settled. Estrogen deprivation at a young age paves the way for serious and premature osteoporosis, something you don’t want to happen.

DEAR DR. DONOHUE: My husband, 44, was diagnosed with diabetes last year. He was a little overweight then, about 10 or 15 pounds. His doctor put him on a diet, and he began to exercise regularly, mostly the treadmill kind of thing. For the past four months he has developed an interest in bodybuilding. He does muscle-building exercise three times a week. As a result he has put some weight back on. He says, and I agree, that it is not fat weight, but muscle weight. He says that is good for him. Is muscle exercise really good for him? — A.S.

ANSWER: Muscle exercise – weightlifting or resistance exercise, or whatever you want to call it – is good for everyone, people with diabetes included.

A gain in muscle weight is a boon for diabetics – and others. Muscle is an actively metabolizing tissue. It burns calories even when a person is at rest. So it is a definite help in controlling blood sugar.

Fat should constitute only 10 percent to 20 percent of the body weight of a man your husband’s age (15 percent to 25 percent of a woman’s). How can you tell how much of your weight is fat? It’s not easy. One way is to compare body weight when taken submerged under water to body weight taken on dry land. That’s not a test readily available to most people. Percent body fat can also be measured by gadgets that shoot a bit of electrical current through the body. That too is not available to many. However, measuring the width of skin pinches is possible and can be done by many people. The process is easy. Calipers measure the width of skin folds at various sites in the body, and those measurements disclose the percent of body weight that is fat.

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.