A cup of coffee could help you burn more fat during your workout, say researchers.
A cuppa could help you run for longer
Australian researchers found that even a small quantity of caffeine allowed athletes to exercise almost a third longer.
A single cup of coffee may be enough to trigger these beneficial effects.
The Australian Institute of Sport team found that caffeine triggers the muscles to start using fat as an energy source rather than carbohydrate sugars.
Caffeine has been used by many endurance athletes as a way of eking extra energy out of their body's reserves during an event.
The researchers tested its effects on cyclists, who were allowed to sip on flat cola or coffee as they pedalled.
Those who did were able to keep going longer than those who stuck to water.
Britons spend an estimated £2 billion on caffeinated drinks each year, but are often advised to steer clear of coffee or cola before exercise because the belief persists that it has a diuretic effect that could contribute to dehydration.
This, says sports dietician Jane Griffiths, is actually a myth.
She told BBC News Online: "If you drink a large quantity of caffeine - perhaps 300 milligrams, which is equivalent to eight cups of tea - in one sitting, there might be a diuretic effect, but not if you drink this amount over a day."
She said that taking caffeine prior to exercise might help not only elite athletes, but also amateur players.
Unfortunately, she says, taking caffeine but foregoing the exercise does not result in fat-burning - both have to be combined.
Other studies also suggest the beneficial effects of caffeine during exercise, delaying the onset of fatigue by up to 60%.