Running takes a toll on the digestive tract

DEAR DR. DONOHUE: I’ve been preparing for a 10K (6-mile) run, and my digestive tract is rebelling. A couple of times I felt like throwing up. On two other occasions, I started to get diarrhea, and it’s a good thing there were public restrooms nearby. Is there something wrong with my digestive tract? — B.K.

ANSWER: Many runners, especially distance runners and runners who are increasing their running time, suffer from digestive-tract woes. One explanation is that running diverts blood from the tract to leg muscles. The blood flow can diminish by as much as 80 percent. The sudden decrease in blood supply leads to all sorts of problems. One is diarrhea. In addition to a decrease in its blood supply, running jostles the colon. The colon’s principal function is to reabsorb water from undigested food. These two factors interfere with water absorption, and diarrhea results. Nausea and vomiting during or after a long run are somewhat common. The stomach doesn’t empty as quickly as it usually does. Food and digestive juices stay in it longer. And the stomach is jolted around just as the colon is. Nausea results, and vomiting may follow. Heartburn is another problem. It’s due to the same things that cause nausea — a delay in stomach emptying and the stomach bouncing around. Since the stomach stays full, it is inclined to get rid of its contents by belching them up into the esophagus. Many of these running effects can be eliminated by eating at least three hours before exercising. The meal should be low in fat. Also cut back on fiber and milk. Hydrate yourself before and during running. Don’t drink any beverage that has more than 8 percent carbohydrate. These stomach problems are not usually an indication of any serious health condition.

DEAR DR. DONOHUE: A friend tells me that lowering a weight is more important than lifting it. He can’t explain why. I have my doubts. It’s a lot harder to lift a weight than it is to ease back down. Will you give your stand on this? — H.D.

ANSWER: I’m with your friend. Muscles contract concentrically and eccentrically. A concentric contraction is one where the muscle shortens when it contracts. With an eccentric contraction, it lengthens. A biceps curl gives you a picture of this. When you lift a weight from the waist to the shoulder, the biceps muscle — on the front of the upper arm — contracts. You can see it bulge. That’s a concentric contraction. Lowering the weight back to the waist, the biceps lengthens — an eccentric contraction. Eccentric contractions produce greater strength and build larger muscles than concentric contractions. That’s been proven by many studies. The message is to take more time lowering the weight than raising it. You can’t let the weight just fall down. You have to resist it all the way down to the starting position.

DEAR DR. DONOHUE: My wife has started jogging with me. She gets a pain in her side from time to time, and she has to stop. What is this? — G.M.

ANSWER: It’s probably a side stitch. It’s believed to be a cramp in the diaphragm, the large muscle that stretches from one side of the body to the other and partitions the chest from the abdomen. It’s the principal breathing muscle. To prevent a side stitch, your wife should exhale forcefully when her left foot hits the ground. If the pain is on her left side, then she exhales when the right foot strikes the ground. To put an end to a stitch, she should bend over and exhale through pursed lips. Or she can raise both arms overhead while inhaling deeply. Then she lowers the arms while forcefully exhaling and simultaneously tightening the abdominal muscles.

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 www.rbmamall.com.