Effect Measure

Swimming and the “one hour rule”

A recent news article by Helen Branswell of Canadian Press (“Wait an hour to swim after eating? Says who?”) contained two pieces of information, one that surprised me and one that didn’t. Branswell was writing about the well worn safety advice to wait at least an hour after eating before going in swimming. This was a rule I remember as far back as I remember anything about what I was told about water safety. She points out that no one seems to know the basis of the alleged fact that to do otherwise courts the risk of developing muscle cramps that could lead to drowning. The theory, as I remember it, was that blood needed by your muscles was being diverted to your intestines for digestion. Not enough blood in the muscles led to cramps. Cramps while in water over your head might make it impossible to stay with your head above water. Etc.

Branswell quotes a sports physiologist to the effect this is unfounded, that in fact the coaches of elite swimmers will often encourage them to take some high energy food just prior to a race. That’s not exactly the same thing as eating a full meal, but it certainly doesn’t fit with the “nothing by mouth” rule many parents adhered to with their sweltering little ones on hot summer days at the beach or pool. Nor does it address whether there is any validity at all to eating food and the risks of muscle cramps, in or out of the water. But I wouldn’t be a bit surprised if there was simply nothing to it — at all. So that’s the part that didn’t surprise me.

The part that did surprise me, was that whatever the evidence, this rule was no longer being repeated by parents. Since today’s parents almost certainly learned the rule as children and I know of no actual evidence to demonstrate it is wrong (nor does Branswell cite any, and she is a very thorough reporter), this means it just “went out of fashion” to teach this to children. I don’t think I taught it to my children (they are grown now with children of their own), but I don’t remember if I did or not and if not, why not. It’s rather curious that, like water, it has just evaporated.

I am assuming, of course, that it has gone out of fashion. Has it?


  1. #1 Ian
    July 16, 2008

    Heaven forbid we should drown ourselves in rules! 😉

  2. #2 Annodeus
    July 16, 2008

    There’s been a good deal of debunking of this going on for some time. There’s even an entry about it on Snopes.com. I think baby boomers, to our credit, have been a thinking generation and have tended to question many old wives’ tales, not just this one.

  3. #3 Mike Dunford
    July 16, 2008

    We definitely haven’t taught it to our kids. And they swim a lot. In fact, my daughter usually has either a large snack or dinner before workout – as is advised by the coaches she’s worked with.

  4. #4 yttrai
    July 16, 2008

    An HOUR? That would have killed us! It was 20 minutes in my hometown, and that was only on the public beach. And that was still the longest, most excruciating 20 minutes of the entire day.

    And our version of the old wives’ tale involved the cramp in your stomach, not some random muscle around the body.

  5. #5 peggy
    July 16, 2008

    Next time you’re at the beach, take a look around. Most kids, when not actually in the water, are snacking nonstop on chips, soda, and other junk. If they had to wait an hour, they’d never get wet!

  6. #6 dave
    July 16, 2008

    I’ve worked as a lifeguard at a camp, and we were very careful to make sure that *everybody* was given this warning.
    We had a few discussions on whether it was valid and none of us really believed it, but it was a wonderful excuse to finish our lunch and get things set up without having to rush.

  7. #7 Julie Stahlhut
    July 16, 2008

    My mother was so credulous of this that she didn’t like my taking a bath within an hour after dinner. (She figured that being in water could magically make you die of cramps if you’d just eaten.)

    After I reached the age of menarche and realized that no one actually died of cramps, no matter how much they could make you wish you were dead, I stopped taking the whole thing too seriously.

  8. #8 GeoIndiana
    July 16, 2008

    As a child, we were literally fish spawn instead of human offspring. We spent hours in the pool and snacked instead of eating huge lunches. Wait to swim, bite your tongue.
    It was the same deal for treks out in the desert where we lived, we snacked and drank all along the trails and this was back in the 60’s and 70’s.
    As an adult (50) if I don’t eat something before vigorous exercise, I get very light headed and disoriented. I have to eat something before swimming or I could drown!

  9. #9 Nathan
    July 17, 2008

    I always thought the main reason for this rule is that people didn’t want kids throwing up in their pool after running around and swallowing water. Less mess to clean up.

  10. #10 pft
    July 17, 2008

    The rule was to not go in water over your head after eating a full meal for 1 hour since strenuous exercise after a large meal does cause cramping, at least I found this to be true in my other activites.

    Even the American Red Cross recommends that you wait until digestion has begun, especially if you’ve had a big fatty meal and you plan to swim strenuously. How long is this? Who knows, 1 hr sounds a safe bet.

    There was never any rule about going into the water after eating a snack that I knew about.

  11. #11 Crudely Wrott
    July 18, 2008

    It is likely that the reason that this ‘rule’ is no longer taught and enforced by parents of late is because of the accumulated evidence gathered by those who broke the rule. Ya’all did break the rule, didn’t you?

  12. #12 themadlolscientist
    July 18, 2008

    When I was growing up, it was supposedly a half hour, but it was kind of a moot point because [1] our local pool was positively Fascist about not letting anyone in the gate if they were carrying anything remotely resembling food, and would ban you for the rest of the summer if you were caught with it once you got inside, [2] they were equally Fascist about making everyone take a real shower before getting in the water, and [3] it took a half hour to get there in the first place – so not much chance of anyone finding out if it was really true.

    But I’ve never given much credence to that rule anyway, and now I’m hearing more and more that it’s being thrown out. Good riddance. It’s always sounded to me like one of those fastidious Victorian holdovers. Who needs ’em?

  13. #13 Christophe Keller
    July 18, 2010

    If I remember right, I was taught this rule as a kid because when we were learning how to swim, usually we would swallow a lot of water. And if we had an undigested meal in the stomach, it could mean we would quickly throw up…