Ergogenic aids for sports performance are not a new topic for research but there is always room for new evidence to support existing arguments. A paper by Coghill and co-workers at the Exercise and Health Research Unit at the University of Bristol investigated the effect of caffeine ingestion in competitive female runners - much of the previous research has examined males.

Eight females were asked to run for 40 minutes at an intensity of 65% V02max on two occasions, one with a caffeine supplement of 7mg/kg of body-mass and the other with a placebo. The physiological responses were measured during each of these submaximal efforts on the treadmill, as blood was taken at 5,10, 20, 30 and 40 minutes during each run. The rating of perceived exertion (RPE) was also noted for each subject under each condition to enable a comparison.

It was found that the caffeine ingestion before exercise led to a decrease in the RPE of the runners as well as an increase in the blood glucose during the 40-minute run compared with the placebo condition. The implication is that such caffeine supplementation could be of benefit to endurance performance, though it should be stressed that the run performance used here was submaximal and not a replication of a race situation.