Spit or swallow? Photo via flickr by hbp_pix

by Josh Liberles

A recent series of studies conducted at the University of Birmingham in England sought to decipher why carbohydrate solutions measurably increased performance in cyclists and runners, even when the length of the event was too short for the body to process the consumed carbs and replenish glycogen stores. As a recent article in the Journal of Physiology reveals, the mouth has receptors that detect the presence of carbs, which triggered a response in the brain and improved performances.

Physiologists commonly attest that there’s no need to bring on calories for intense activities which last an hour or less (sound like a familiar event duration, cyclocrossers?). The body should have more than enough stored glycogen present to adequately cover the efforts. But they did detect improvements in performance among athletes who consumed carbs during exercise durations lasting less than an hour. Intravenous glucose supplementation was not found to yield the same results, which led the researchers to focus on the mouth. Saccharin, maltodextrin and glucose solutions were all tested, with the two carbohydrate solutions – maltodextrin and glucose – the only two yielding a positive change. Thus the presence of sweetness alone didn’t trigger an increase in performance; it was something specific about carbs.

The athletes used a mouth rinse of the various solutions, which they then spit out. Cyclists and runners found increases in performance of up to 14% – and the benefit was the same whether they spit or swallowed. The disadvantage of swallowing is that cabrs in the stomach cause blood to be diverted there for digestion, which can lead to stomach cramps or could be a performance disadvantage in and of itself.

“You can get an advantage from tricking your brain,” Matt Bridge, a senior lecturer in coaching and sports science at the University of Birmingham in England told the New York Times. “Your brain tells your body, ‘Carbohydrates are on the way.’ ” And with that message, muscles and nerves are prompted to work harder and longer.”

So what does this mean for cyclocrossers? Will we see our Elite athletes sipping and spitting a la a wine tasting or, perhaps, a western-style saloon, complete with spittoons lining the starting grid? Not likely. But for those who have a tough time processing calories during intense bouts of exercise, a mouth rinse could be just the ticket to help you hold your own in the sprint off the line.