DEAR DR. DONOHUE: I have been aqua jogging for one month, doing up to 2.5 hours in the pool. I plan to run a marathon in two months, and I do all my training in the pool. I have run more than 80 marathons, so I’m no stranger to the distance. I have iliotibial band syndrome, and my knee seems to be doing better. By the end of two months, I hope to do sessions lasting up to four hours in the water. What do you think of water jogging for a long-distance runner? – C.R.

I think you have made an excellent compromise by continuing your exercise in water with your injury. I don’t think, however, that you can rely solely on water jogging to prepare for a marathon, even if you have 80 marathons under your belt.

First, there is the problem of specificity. Each sport and each exercise involves different muscles in different ways. The only way to achieve top performance in any given sport is to exercise your muscles in exactly the same way they are used in that sport.

Second, water running requires less effort than land running. That’s due, in part, to the buoyancy of water. In water at chest level, the legs have to support much less weight than they do on land. Furthermore, heart rate during water exercise never reaches the same level that it does on land.

Third, the temperature of pool water stays the same. Your land exercise is subject to temperature changes, something that the body must get used to.

Water running, in one respect, is more taxing than land running because water resistance is much greater than atmospheric resistance.

When your knee pain has gone, it would be wise of you to start land running – at distances far less than a full marathon.

C.R.’s injury is iliotibial band syndrome. The iliotibial band is a wide swath of tough tissue that runs down the outside of the thigh from hip to knee. It’s involved in many leg motions. Inflammation of the tissue leads to pain on the outer side of the knee. Rest and anti-inflammatory medicines can usually put an end to pain.

DEAR DR. DONOHUE: I am interested in learning how much protein is recommended for athletes. Where do I get it? – L.F.

DEAR DR. DONOHUE: Is it true that protein gives life, but protein will eventually kill you? – O.R.

The daily recommendation for protein is 0.8 grams for every kilogram (2.2 pounds) of body weight. Some nutritionists would increase the amount of protein for athletes engaged in demanding exercise. Food protein is needed for body protein synthesis. When protein synthesis exceeds protein breakdown, muscles become larger and stronger.

For a 175-pound (79 kg) man, the daily protein requirement is 65 grams, a little more than 2 ounces. For a 130-pound (59 kg) woman, the daily requirement is 47 grams, about 1.5 ounces. Three ounces (not a very big serving) of lean meat, fish and poultry have 18 grams to 24 grams of protein. One cup of low-fat milk has 8 grams. One-half cup of cooked beans has 7 grams. It is not hard for anyone to get the recommended daily amount of protein.

Protein gives life, but so do carbohydrates, fats, vitamins and minerals. Proteins will kill you? No. If you’re talking about the altered proteins called prions, write me again.

DEAR DR. DONOHUE: I am 63 years old and do walking aerobics three days a week, and upper-body strength training with dumbbells and lower-body strength training with ankle weights twice a week. I also walk 30 minutes to 45 minutes five days a week. Is it necessary for me to walk on the days I do walking aerobics? – L.M.

No. You’re doing plenty of exercise.

If you can do more, however, the more exercise you get, the better off you are.

DEAR DR. DONOHUE: I am a middle-aged man who is very thin. I have a number of stomach disorders. Because of those disorders, I drink a lot of soy milk and eat lots of whole grains, soy, yams and nuts. This diet helps my stomach.

In the past few years, I have developed breasts, a condition for which my doctor has no explanation.

Recently, while searching the Internet about breast growth, I was surprised to discover that these foods are classified as phytoestrogens. Could they be the cause of my breast growth? – R.A.

Phytoestrogens are compounds found in some plants that have weak estrogen (female hormone) activity. Soy, chickpeas, rye, carrots, peas and spinach are a few examples of plants with phytoestrogens.

Phytoestrogens are not on every list of causes for gynecomastia (GUY-nuh-coe-MASS-tee-uh), the growth of male breasts. In fact, they are on very few lists. I take that to mean they aren’t a common cause of it.

However, the potential for them to stimulate breast growth is there. The only way I can see for you to prove it is to eliminate some of the higher-phytoestrogen-content foods, like soy, from your diet and see what happens.

Other causes of gynecomastia are old age, liver problems, an overactive thyroid gland, puberty and some medicines. Tumors of the adrenal gland and testes can bring it on, but those instances are rare.

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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