Carbohydrate Drinks – Spit or Swallow?

Everyone knows that carbohydrate drinks can enhance performance, but new research suggests that actually swallowing your favourite sports drink might not be necessary. Strange as it sounds, you can rinse your mouth, spit the drink on the ground and still be faster!

Asker Jeukendrup, who is Professor of Exercise Metabolism at the University of Birmingham (UK) has done extensive research into this and his findings are quite surprising.
There is evidence that taste influences mood and it may also influence the perception of effort. An interesting observation provides support for a central nervous system effect. When you are hypoglaecimic after a long run and you are feeling weak and dizzy, all you have to do is to bite into a chocolate bar to feel better. Almost instantly the feelings of weakness and dizziness are reduced, and you feel better long before the carbohydrate has reached the blood circulation and the brain. This means that there must be connections from the mouth directly to the brain.

Controlled tests with athletes at Birmingham University showed that the time to complete the test was shorter with the Carbohydrate mouth rinse than with the placebo: 61.7 minutes to 64.1 minutes. Interestingly when drinks were swallowed and not rinsed, there was no difference between the placebo and carbohydrate drinks.

Asker Jeukendrop’s findings suggest that there are receptors in the mouth that detect carbohydrate and that these receptors are separate from the receptor that detects sweetness. However “carbohydrate receptors” have not yet been identified in humans.

Carbohydrate ingestion seems to work when the exercise is longer than 30 minutes. Exercise shorter that that does not seem to benefit from carbohydrate intake, so overall, the effect of a carbohydrate mouth rinse is convincing and seems to be significant for exercise lasting 30 – 60 minutes.