mythbuster graphic For a child, 30 minutes can feel like 30 hours, especially when he or she has just eaten lunch and is itching to get back into the pool, ocean, or lake. We've all heard the instructions to wait a half an hour after eating before we re-submerge. Most of us have probably followed this advice, and as adults, we’ve probably even given these orders. But is the wait really necessary? Does a full stomach increase your chances of drowning?

The theory may be routed in a fear that exercising on a full stomach can cause abdominal cramping which could lead to impaired ability to swim and potential drowning. However, no medical or biological evidence seems to support this claim. That means that you—and anxious children everywhere—can actually swim safely after a snack or small meal.

Evidence for the Health Claim

As with any exercise, vigorous swimming immediately following a heavy meal could cause some discomfort—and may certainly cause cramping. Cramping could impair a swimmer, and it’s hypothetically possible that severe cramping could prevent a swimmer from being able to safely reach the shore or pool’s edge in time to recover. So, in theory, cramping this severe could potentially lead to drowning.

Digestion does reduce the amount of blood circulating to the muscles to some degree, because additional circulation is needed to aid the digestive process. With a reduction in the amount of blood—and thus oxygen—muscles receive following a large meal, muscle cramps are more likely during any exercise undertaken soon after. However, some refute this claim, saying that the body's oxygen supply is more than sufficient to keep both digestion and muscles working properly.

Swimming on a full stomach may also lead to other types of discomfort, such as heartburn or vomiting. If a swimmer—particularly a child—began vomiting while swimming as a result of a full stomach, the risk of drowning would certainly increase.

One type of substance consumed before or during swimming is indeed dangerous. Alcohol can severely impair judgment and physical ability. This can lead to drowning, and often has. Studies have shown that 25% of teenage drownings and 41% of adult drownings were alcohol-related.

Evidence Against the Health Claim

No cases of drowning caused by swimming on a full stomach have ever been documented. In addition, neither the American Academy of Pediatrics, the US government’s Consumer Product Safety Commission, nor the Red Cross offers any guidelines or warnings related to swimming after eating.

Actually, exercise of any kind is not recommended on a completely empty stomach, and many experts recommend a small snack before or even during exercise to keep up energy levels.

If a muscle cramp from eating were to occur, most swimmers would likely be able to get themselves out of the water before impairment became so severe that drowning occurred. However, children should always be well-supervised while swimming, no matter when they last ate.

Conclusion

If you've just eaten a big meal, common sense will tell you that swimming may not be the best way to help settle that full stomach. Small children, who may get rambunctious and excited (and clumsy!) after a meal, may also want to take a precautionary break before their aquatic acrobatics resume. But these actions are likely to have a minimal effect on the risk of drowning. In the end, with no documentation to link post-lunchtime swimming with drowning, this threat doesn’t really hold water.