Should you not swim straight after eating?
People often say you should never swim straight after eating lest you get a stomach cramp. It’s never clear what this means but it sounds nasty. The unspoken implication is that those foolhardy enough to take a dip on a full stomach will at best lose their lunch and at worst lose their life. In fact, they are risking nothing.
Consider these mysterious stomach cramps. Have you ever had one, or met someone who has?
Now, it is true that the stomach can get up to high jinks. Digestion begins in the stomach with acid release and peristalsis — slow waves of muscle contraction that push food ever onward. Under some circumstances the stomach’s normal activities are interrupted — but swimming isn’t one of those circumstances. High emotions can do it, but exercise on its own generally does not.
Even if the stomach does depart from the scheduled programme, there’s no reason for this to cause you to plummet to the bottom like a stone. Exercise of any kind on a full stomach won’t find you at your physical peak, and may be uncomfortable, but it isn’t dangerous.
You don’t need to be a doctor to work out that there’s something very suspect about the whole thing. If this was a real problem then we should expect some authority somewhere to take it in hand. The summer is full of cutesy characters telling us to watch ourselves: the tiger prawn telling us to slip, slop, slap and wrap, the life preserver telling us how to keep food safe, that bucolic cartoon chap telling us not to burn down the countryside. So where’s the animated duodenum exhorting us to wait an hour after eating before diving in?
And why only swimming: if it’s the exertion, then why are we allowed to take a walk or run after lunch, and why don’t labourers pause to digest before getting back to the heavy lifting? If it’s the water, why are we not told to stay out of the shower and bath as well?
This is the kind of science anyone can do in their head, perhaps over lunch, before taking a pleasant post-prandial dip.