Thursday, June 29, 2006

Waiting 30 minutes to an hour before you swim…my mom says the principle isn’t a myth.

So, I talked to my mom yesterday and she stuck to her guns about waiting to swim after you eat. She said there are physiological reasons to wait. It’s mostly a matter of blood flow. If you’ve eaten right before swimming, oxygenated blood is being shunted toward your gut (GI track, stomach ect.). Poor blood flow might lead to lactic acidosis, which causes cramps. She said that a cramp while you’re running or doing some sort of land based exercise might be painful, but in water, difficulty moving muscles could lead to drowning. She then referenced Harrison’s Principles of Internal medicine Braunwald “Lactic acid is produced at accelerated rates in skeletal muscle and other tissue whenever oxygenation is inadequate to supply energy needs.” I told her that I believed her. She said that the reason, many people probably consider this rule an old wives tale is because it’s imprecise. The amount and type of food you’ve eaten will have an impact on cramps. 30 minutes might not be enough if you’ve had a large steak and potatoes and then want to go swim in deep ocean waters.
That made sense to me. My mom is a radiologist so the studies she’s conducted had nothing to do with cramps, but there are doctors that have studied the subject. Doctors Darren Morton and Robin Callister have extensively studied stomach cramps related to exercise which they call “exercise-related transient abdominal pain (ETAP) or stitches. Dr. Callister said that “you are most likely to get a stitch if you've consumed food or drink fairly shortly before you exercise” (MSN). So there is some truth to waiting to eat before you swim. Callister and Morton did say that the type of food makes a difference because carbohydrates will be burned faster than protein or fat. In the article they discuss this subject in mentions a professional swimmer that eats all the time during her swims. Here’s the article.


Blogger LDD said...

As an experienced swimmer (and as one who regularly swims laps for exercise), I would add that having anything on the stomach that can be regurgitated and aspirated increases one's risk of drowning and this not merely from "stomach cramps." It is not at all unusual while swimming to cough or burp whether voluntarily or involuntarily. Either of these actions can push stomach contents into the esophagus, a very unpleasant experience which can in turn result in gagging, choking, aspirating, and, ultimately drowning. All one needs to initiate a cough while swimming is a bit of water down the windpipe. This is quite common, especially in waves or swimming near others who disturb the water. So is a even a mild cough due to allergies a/o exercise-induced asthma. A simple burp is even more likely to cause stomach contents to "rise" in the now horizontal esophaogus. And this can be casued by something as simple as having had a can of soda or swallowing some air while swimming. I have personally experienced all of these regurgitation scenarios while swimming both in the pool and in open water. I have never yet aspirated, but I've come close enough to know that it could happen to anyone - including me. An episode at the local pool where others may come to your aid or you may even be able to stand on bottom is one thing. Alone in open water, swimming with anything on your stomach can be deadly, even to the most experienced swimmer.

4:08 PM  

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