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Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "

03.01.2011

Endurance athletes are faster if they just taste carbs and spit them out

Sports scientists are scratching their heads over a recently discovered inexplicable phenomenon that helps endurance athletes to improve their performance. Athletes who swill their mouth out with a sports drink containing fast carbohydrates, and then spit it out, clock up better times than athletes that swallow the drink. Sports scientists at Ghent University published a new piece in the puzzle not so long ago.

That athletes' performance improves if they drink a sports drink after they've already been going for 2 or 3 hours is logical. They are going through their glycogen reserves and their glucose levels are falling. But it’s still not clear how sports drinks boost performance in athletes who have only been active for an hour or less. The body of an endurance athlete should have sufficient reserves of its own.

One possibility is that the performance enhancing effect starts in the mouth. Recent studies have shown that athletes perform better if they rinse their mouth out with a sports drink and then spit it out.

The Belgian researchers got 12 trained triathletes to do a certain amount of work on a bike. If the athletes were to cycle continuously at 75 percent of their maximal capacity, then the exertion test would take them 1 hour.

On one occasion the triathletes were given 14 ml Gatorade per kg bodyweight [carbohydrate electrolyte solution or CES]; on the other occasion they were given a zero-calorie placebo sweetened with aspartame. Gatorade is an isotonic sports drink, containing 6 percent simple carbohydrates. The athletes divided the drink over the duration of the ride. Each time they had to either swill liquid around in their mouth for 5 seconds and then spit it out [rinse], or swallow it immediately.

The triathletes who just rinsed with the drink clocked up 3.7 percent shorter times than the others. The rinsing boosted the amount of exertion the athletes could manage per unit of time.

The rinsing raised the concentration of lactic acid in the blood. Lactic acid is released when muscles burn carbohydrates. Apparently the rinsing stimulates glucose oxidation.

The researchers suspect that the sports drink doesn't have the same effect if you just swallow it because ingestion is so quick. It seems that there are carbohydrate receptors in the mouth that stimulate the body's glucose burning.

Source:
Scand J Med Sci Sports. 2010 Feb; 20(1): 105-11.