KEY POINTS:
Swilling an energy drink around the mouth rather than than swallowing it can give athletes the same performance boosting results without the high calories, New Zealand research has found.
Rinsing with the sports drink - which includes carbohydrates, a source of sugar to power the muscles and salt,
fools the brain into thinking it has more energy - which could be a boost to people who want to lose weight in gyms.
Auckland University sport science lecturer Dr Nicholas Gant said yesterday the role of sports drinks in helping to delay fatigue in prolonged exercise was well established.
But research now suggests the mouth might contain carbohydrate receptors that trigger a chemical pathway in the brain even before carbohydrates are consumed and begin their conversion to glucose.
Dr Gant, who will present his findings to a "functional foods" symposium on Thursday, said that in trials of sports drinks, both drinking and just mouth-rinsing, people felt better on a treadmill and exercised at a higher intensity than they thought they were. "Perhaps we can in future come up with ways to trick the brain into thinking the body has higher energy status than it does.
"[Mouth-rinsing sports drinks] could help people with adherence to exercise programmes ... without affecting energy intake." But his expert area was high-performance sport and he warned that sports drinks could be unhelpful for people going to the gym for weight loss.
Dr Gant said the way in which carbohydrates affected the brain without entering the blood was unclear.
Following a trial in which cyclists' performance in a time-trial improved significantly after a mouth-rinse of a carbohydrate drink, it was thought carbohydrate receptors in the mouth and possibly elsewhere might influence chemical pathways in the brain linked to motivation and reward. The brain seemed to anticipate the delivery of glucose to the blood.
"These mechanisms possibly result in alterations in mood and motivation during exercise and/or influence the subconscious control of a pacing strategy," Dr Gant said.
In separate research, he is investigating the effect of putting caffeine, which enhances performance, into sports drinks, testing the new brew on soccer players' ball-kicking accuracy.
Other studies have shown a lowered perception of work-rate following consumption of a caffeine drink, and an improvement in performance after a caffeine-carb drink that is comparable to that seen only with larger doses of caffeine alone.
But Dr Gant said knowledge was scant on the effects of caffeine on motor-skills.