Caffeine and carbohydrates help athletes recover faster after workouts, Australian study shows.
Researchers at the RMIT university have found that glycogen - the main fuel source for muscles- is replenished faster when athletes consume both caffeine and carbohydrates after exercising.
Senior author, Professor John Hawley, said the research found athletes who added caffeine to their post-exercise meal had 66 per cent more glycogen in their muscles than those who ate only carbohydrates.
"While it's been established that carbohydrates and caffeine improve a variety of athletic performances, this is the first study that has revealed that combining caffeine with carbohydrates after you've exercised can actually help your muscles refuel more rapidly."
Professor Hawley said the research could help elite sportspeople such as Olympic athletes, who were looking for an edge over their competitors.
"But because caffeine can potentially have negative effects - such as disturbing sleep or causing the jitters - athletes who want to incorporate it into their recovery routines should experiment and see what works for them well before any serious competitions," he said.
The study involved four assessment trials with seven endurance cyclists, who were given either a plain carbohydrate drink or one with caffeine (8mg per kilogram of body weight or the equivalent of 5-6 strong cups of coffee).
The cyclists rode a cycle ergometer until exhaustion and four hours later, those who had consumed the drink containing caffeine had 66 per cent higher glycogen levels in their muscles compared to those who had the carbohydrate-only drink.
Professor Hawley said it was not clear how caffeine helped to facilitate glucose uptake from the blood into the muscles, however higher circulating blood glucose and plasma insulin levels were likely to be a factor.
"We think caffeine may also increase the activity of several signalling enzymes that play roles in muscle glucose uptake during and after exercise," he said.
Considering the side-effects of drinking too much caffeine, the next step for the researchers will be to discover whether smaller doses of caffeine could be just as effective in helping the muscles convert carbohydrates to glycogen more quickly.
The study, "High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is co-ingested with caffeine", was conducted by researchers from the Exercise Metabolism Group in RMIT's School of Medical Sciences.
The RMIT study has been published in the prestigious Journal of Applied Physiology.