1 April 2013
Should you wait an hour after eating until swimming?
We are told taking a dip on a full stomach is dangerous because we might get cramp or a stitch, or even drown. But is there any truth to this?
I can still remember how slowly time seemed to pass as a child when I was on the beach, and had to wait an hour after I’d finished my sandwiches before I was allowed back into the sea. The reason, I was always told, was that swimming on a full stomach is dangerous because you might get cramp or a stitch, leaving you unable to swim, and this could result in drowning. But is there any truth in it?
The causes of are cramp still aren’t fully understood, as I’ve discussed previously. There’s no evidence to suggest that exercising after eating gives you cramp, but what we do know is that vigorous exercise directs blood flow away from the digestive area to the skin and to the muscles in your arms, legs and skin. So, if your food is still half-digested this could make you nauseous. It’s the same reason that extreme fear makes you feel sick. The fight-or-flight response abandons less-urgent processes like digestion, diverting blood flow to the muscles so that you can defend yourself physically, or run faster than you ever have before.
But these studies on cramp involved athletes taking part in long-distance running or even triathlons – involving a lot more vigour and endurance than the kinds of splashing about kids are more likely to do on holiday. Professional swimmers are careful not to race on a full stomach, but they do ensure that they have eaten enough to provide the fuel needed for them to perform at their best. When endurance swimmers undertake very long distances they even consume food during the race. If they do experience cramp, it’s more a result of overexertion, it doesn’t seem to be related to food.
So how about a stitch? Although this can feel like cramp, researchers differentiate between the two. Despite having been given the medical name of “exercise-related transient abdominal pain”, stitches are still not fully understood. In Australia sports scientist Darren Morton has devoted his research career to the subject of the stitch. He’s found that elite swimmers are even more prone to getting a stitch than runners. People who had eaten a large meal between one and two hours before a race were more likely to get a stitch, even though they had waited the requisite hour before exercise. (He does have one bit of good news, though – the older you get, the rarer they become. (...)
Continue reading: http://www.bbc.com/future/story/20130401-can-you-swim-just-after-eating/print