Many people remember waiting an hour, half an hour, or at least 20 minutes after having had lunch before they could get back into the swimming pool. In Cuba, children are told they must wait three hours to swim after eating. Parents and grandparents might explain the wait by telling children with tales of how cramps could occur, causing drowning. Of course, water safety is of utmost important for all swimmers, but it's unlikely that swimming immediately after eating, especially if a person doesn't swim very vigorously, will lead to dangerous cramps.
The basic premise behind this caution is that food digestion requires greater blood flow to the stomach. Exercise also requires greater blood flow to the arms, legs, lungs, heart, and other organs. This may deprive the stomach of a certain amount of oxygen, causing a muscle cramp, sometimes called a stitch, to occur. Most medical professionals suggest that these cramps are mild, and provided a swimmer doesn’t freak out in the water, some floating will help minimize any cramping, if it even occurs. Eating a huge meal and then swimming a triathlon is definitely not recommended because of the amount of blood supply needed for the arms and legs, and it could result in cramping and vomiting, but is very unlikely to result in drowning.
A better caution would be to recommend people don’t vigorously swim after eating. Playing in the water or swimming a little bit is unlikely to increase the possibility of drowning, however,. This is an urban legend or old wives tale that a number of mythbuster groups have debunked thoroughly. Research on this matter suggests that there has never been an instance of drowning attributed to eating shortly beforehand.
Another, similar myth is that people also should not have a bath after eating. This will cause, according to some, poor digestion of food or possible drowning. One suggestion for the origin of this second myth is that eating slightly raises body temperature, so if someone takes a really hot bath after eating, he or she might overheat and faint. Another is that bathing after eating could cause slight cramping of the stomach because some bloodflow gets diverted to the skin’s surface.
Probably more importantly, if someone lying down in a bathtub and is prone to acid indigestion, not sitting up fully may make heartburn occur with more frequency. Some suggest waiting about 20 to 30 minutes after eating before taking a bath to avoid acid indigestion. There is little indication though, that bathing after eating would cause cramps that might make a person drown.
Of course, it is always good advice for individuals to pay attention to how they are feeling when they bathe or swim after eating. If someone over ate and feels nauseous, he or she may want to hang out and digest before hopping into the water, especially for very strenuous activity. When a person does start to develop a stitch, he should make his way out of the water and take a break for a while. Sudden cramping of arms or legs should be met with calmness, and floating while taking deep breaths can help eliminate the problem.