The Science of Swimming and Eating
In layman’s terms, when swimming or performing any kind of exercise, your heart rate increases and pumps more blood to your working muscles, providing them with necessary oxygen as well as increasing blood flow to the kidneys to rid the body of waste produced in the form of lactic acid and ethanol.
When you eat, your cardiovascular system increases blood flow to the stomach to aid in digestion and to your intestines to maintain the constriction needed to move the waste through your bowels.
Herein lies the science behind the idea that you should not immediately go swimming after eating. Your body is using increased blood flow to digest your recent meal, diverting it away from the muscles you need in order to swim.
Myth vs. Reality
Scientifically and biologically, that information all makes sense, but through research and observation, the idea that eating before swimming is dangerous and will lead to muscle cramps has largely been debunked.
Most experts now believe that the body has more than enough blood flow to support all organs and tissues regardless of physical activity, either voluntary (swimming) or involuntary (digestion).
Use Common Sense
If you are recreationally splashing around in the water, then eating before swimming should not be an issue. As with any strenuous exercise, a full stomach may make you uncomfortable and could lead to heartburn, vomiting, and overall malaise.
When you are enjoying a day of water-filled fun, remember the K-I-S-S concept. “Keep It Simple Swimmer!” By that we mean stick to simple carbohydrates like chips and crackers, and snack on fresh fruits and vegetables. Steer away from heavy, fatty meats, or if you just have to have that burger at the beach, try not to overeat.
If you are experiencing swimming cramps, it is probably more beneficial to look at how much you are drinking instead of how much, when, or what you are eating. Being in the sun and surf, you do not realize how much water you are losing from your body. This is exacerbated if you are consuming alcohol. Make sure you are drinking plenty of water and replacing electrolytes with a couple servings of sports drinks as well.
Listen to Your Body
When deciding how long to wait after eating to swim, the answer is really quite simple. You know how you feel, so do what is within your comfort zone. If you are feeling a bit full and need a little time to digest, take a break in the shade. If you are worried about the kids going back in the pool right after lunch, tell them to stay in the shallow end for a bit where the water is not over their heads.
Can you swim after eating? Absolutely! It simply boils down to water safety and how you are feeling. To learn more of the best practices for safe swimming, check out The 411 Book from SwimJim, a terrific water safety program for you and your young water babies.