Is swimming within an hour after a meal dangerous? Will it divert blood flow from your stomach to your muscles and cause cramps?
The answer is no! This has been a popular myth quite related to and as popular as the “don’t exercise after eating” myth. These are notorious not because many people believe them but because they are based on false, unproven science.
This myth started in Cuba, where parents tell their kids not to swim right after eating because swimming with a full stomach can lead to cramping. But medical experts have weighed in on this issue, and most of them have nothing to say about it. Yes, they say it’s not dangerous.
What made this myth popular?
According to its proponents, when you eat, much of blood circulation is diverted to your digestive system, particularly your stomach and small intestine. So supposedly your gut is busy receiving more blood after eating, and you should not do anything that demands blood flow during this period.
Exercise, like swimming, is a demanding activity that prompts your muscles to demand more blood flow. So when you exercise after eating, you divert blood flow from your stomach, and this allegedly creates a sort of an imbalance between the blood received by your stomach and your muscles. According to the myth mongerers, cramps ensue because the muscles receive less blood than necessary. This could even lead to drowning.
However, when you look at the data of people swimming after a major meal, you wouldn’t find documentation of drowning due to a full stomach. There is no significant difference between cases of cramping among swimmers who didn’t eat before swimming and those who did.
It seems as though the people who promoted the myth were misled by cases of swimmers who suffered from cramps after eating, whereas ignoring others who headed to the waters hungry and still suffered from cramps. This is called confirmation bias. It’s when you choose evidence that goes well along with your preexisting bias.
Fact is that there is no scientific evidence that links cramps and drowning with swimming when the stomach is full. But many people don’t know this. In fact, ask anyone about it and they would tell you the prevailing myth. It’s hard to dispel myths. When someone just ate lunch and heads to the water to swim and then feels the cramps, they would most likely blame the meal beforehand. Then there goes the relaying of the myth to friends.
So should people swim after eating?
This is more of a personal question. If you like swimming after helping yourself to bagel, and bagel doesn’t make you uncomfortably full, then by all means go ahead. A lot of people just don’t head to the waters while their stomachs are full because they feel full and heavy. Health wise, there’s really nothing to worry about. Don’t even worry about your blood flow getting diverted from your stomach to your muscles. Your circulatory system is quite good at evenly distributing blood throughout your body no matter what you’re doing.