FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

"OLD WIVES' TALE" STILL GOOD ADVICE FOR SWIMMING AFTER EATING

Question: Is it true that recent research shows it's safe to go swimming after eating? That is what I saw on the internet. They claim that the admonition about swimming after eating is an old wives' tale which most people still repeat.

Answer: Avoiding swimming for at least one hour after eating is much like the advice "don't run with scissors." Both are good general safety precautions but not "hard and fast" rules.

Swimming after eating can increase one's risk of drowning and, therefore, should be avoided. To put it in proper perspective, though, this risk is actually quite small. I'll try to explain why this is so. When we eat a meal there is a dramatic shift of blood flow into the abdomen to sustain the increased muscular activity of the digestive tract. As the demand for blood in the gut increases, less is available for carrying oxygen to the arms and legs. The muscles in these limbs require this oxygen to support the increased activity necessary during exercise like swimming.

It is possible to swim with sufficient vigor that the muscles require more oxygen than the circulation can provide at the moment. Fortunately, the muscles can continue to work in this situation for a while, but their metabolism is shifted to an anaerobic or without oxygen mode. The anaerobic activity causes the metabolic byproduct lactic acid to accumulate in the muscles and in the blood. These changes, along with reduced oxygen level and other metabolic changes can cause muscle cramps.

Despite the heavy metabolic demands of running a marathon, runners don't eat a five course meal just before starting a race. Guess why. Yes, the same reason one shouldn't eat a large meal and then go swimming decreased performance and increased risk of muscle cramps.

Eating a light meal and then playing about in the water is perfectly safe. Situations that require vigorous activity should be avoided after eating. For a novice swimmer, this may be simply trying to stay afloat, for a competitive athlete it may be swimming in a race. In general, the larger a meal the longer the delay before safe swimming. Since most people tend to let their desire to play in the water override their good judgment, the old adage is still the best to follow: Don't go swimming for one hour after a meal. And, for the record, I don't advise running with scissors or playing with matches, either!

Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.