Why shouldn't I swim right after I eat?

The advice to wait before swimming after eating is deeply embedded in popular lore, and one of its most notable endorsements came from the Boy Scout handbook. This influential guide first warned young scouts about the potential dangers of swimming shortly after eating in 1908, suggesting that doing so could lead to muscle cramps and consequently, an increased risk of drowning. The rationale behind this caution was the belief that after eating, blood is redirected to the stomach for digestion, leaving fewer resources for the muscles. If a scout ignored this advice and faced challenges while swimming, the guide said it was his own fault for not heeding the recommended waiting period.

Even though eating before swimming may not increase the risk of drowning, it may not be a bad idea to wait a little bit to jump in the pool after a big meal. If you do hop into the water right after you eat, you could develop minor cramps. Let's look at how this works.

The key to understanding this small possibility is to know that your body will always work to take care of its energy needs and that conflicting needs can cause problems. When you exercise, your body's conflicting needs can cause problems. Here's what happens:

Your muscles need oxygen and nutrients while swimming. The heart pumps blood faster to ensure these muscles get what they need. But when you've just had a meal, your digestive system is also hard at work. It demands a significant blood supply to break down the food and extract nutrients.

So, you have two significant systems competing for a substantial amount of blood supply. Sometimes, under this dual demand, the body might not manage blood distribution efficiently, potentially leading to minor muscle cramps since the muscles might be slightly deprived.

However, it's important to note that the body won't compromise the blood flow to the extent that it would hinder the functioning of arm and leg muscles significantly. Hence, the fear of drowning due to inhibited blood flow after eating a meal is a myth.

Staying hydrated is also important while swimming. As we engage in this form of physical activity, our muscles are subjected to strenuous work, and without adequate hydration, these muscles may cramp. Cramping is the result of an involuntary, sudden muscle contraction that doesn't relax. While several factors can lead to cramping, dehydration is a frequent culprit. So, you may want to drink plenty of water when you swim. By ensuring the body has sufficient fluids, swimmers can have a safer and more comfortable experience.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.