Abstract

The purpose of this investigation was to examine the effects of caffeine, used separately or in combination with glucose, on blood glucose, blood lactate, plasma FFA, respiratory exchange ratio (R), VO2 and perceived exertion (RPE) during an extended submaximal treadmill run. The four treatments administered were: (a) placebo ingested both prior to and during exercise (P + P); (b) caffeine 60 min preexercise and a placebo 30 min prior to and during exercise (C + P); (c) placebo 60 min pre-exercise and 10 glucose 30 min prior to and during exercise (P + G); and (d) caffeine 60 min preexercise and 10 glucose 30 min prior to and during exercise (C + G). Results showed that the P + G and C + G treatments produced significantly higher mean blood glucose levels than P + P and significantly higher blood lactate levels than P + P and C + P. Plasma FFA levels were found to be significantly higher and R values significantly lower for C + P than for the other three treatments. Furthermore, subjects were found to perceive exercise as significantly easier with treatment C + P and significantly more difficult with treatment C + G when compared to P + P. The C + P treatment exhibited the most beneficial effects overall when performing extended submaximal exercise. Verf.-Referat