Want to get a performance boost with very little effort and almost no money?

Here’s a cute trick from the frontiers of sports medicine: instead of swallowing a sports drink, just take a mouthful, swish it around spit it out. Zoom! It will add pep to your step. That’s right. You don’t even have to swallow.

In study after study, researchers have found that just the taste of carbohydrates in your mouth will increase your athletic performance. Apparently your brain interprets the flavor to mean that nutrition is on its way. So it releases energy, in the form of glycogen, to your muscles.

Some of the studies on carbohydrate mouth rinses have included scans of the participants’ brains. Nerve cells fire only when participants get the real carbohydrates, not when they taste artificial sweeteners.

Carbohydrate Mouth Rinses Studied

Granted, carbohydrate mouth rinses will not transform your athletic life. At best they will shave a crucial bit off your time in a close race. “You’re probably going to be in the range of seconds to minutes in an hour-long exercise bout,” says Scott A. Conger, a kinesiologist at Boise State University.

Conger and I met up last week when we were both at the American College of Sports Medicine meeting in San Diego. I was covering the meeting for Medscape, and he was presenting an analysis of 16 studies done on carbohydrate mouth rinses over the past 10 years.

As you might guess, this can only go on for so long. After about an hour, you’ll start to run low on glycogen, Conger says. If you want to get the continued benefit of carbohydrates, you have to consume actual carbohydrates. (Many endurance athletes are training their systems to rely more on fat, but that’s another story.)

So what’s the benefit of spitting out?

Some people don’t want to consume anything when they’re doing intense exercise. Even a sports drink upsets their stomach. Carbohydrate mouth rinses could be a way to get the benefits without the harm, at least for a short bout.

Looking over the literature, Conger came up with a few other conclusions about carbohydrate mouth rinses:

Tips from the Research

• It doesn’t seem to matter whether you eat or not in the hours before your exercise.
• You can probably use any type of carbohydrates. Some studies have used glucose, some have used maltodextrin, and some have used a combination of carbohydrates.
• It works for every kind of exercise where it’s been tried. Researchers have used it in bicycling, running and (in a paper that was scheduled to be presented at this meeting, but wasn’t) weight lifting.
• The bigger the dose of carbohydrates, the bigger the effect. Studies where researchers used a 6-7 percent solution got less than a third of the effect of studies where they used a 10-12 percent solution.

Personally I don’t fit the profile of someone who would benefit from carbohydrate mouth rinses. I don’t compete in time trials. And my stomach doesn’t get upset by a little fruit juice before I run.

But I’d love to hear about your experiences if give it a try.

Photo: “Dorst” by Jos Dielis

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