REPEATED CAFFEINE DOSES MAINTAIN PERFORMANCE LEVELS IN PROLONGED SLEEPLESSNESS
McLellan, T. M., Bell, D. G., & Kamimoir, G. H. (2004). The effect of caffeine on run times to exhaustion 85% VO2max following a night of sleep loss. Medicine and Science in Sports and Exercise, 36(5), Supplement abstract 141.
Soldiers (N = 18) performed a double-blind experiment involving caffeine and placebo conditions where each trial involved a control day and controlled sleep period followed by 30 hours of sustained wakefulness beginning on the second morning. A 400 mg dose of caffeine was administered at 1230 hours followed by a 100 mg doses at 0300 and 0500 hours. Physical tasks, cognitive function, and marksmanship as well as a treadmill run to exhaustion were assessed at 0700 on the third morning.
Caffeine had no effect on heart rate, perceived exertion, or VO2 after 10 minutes of exercise. Time to exhaustion, when compared to the placebo performance, was significantly increased (24%) after caffeine. Caffeine also maintained other performances at pre-experimental levels. There was no difference in caffeine effects between caffeine users and non-users.
Implication. Repeated doses of caffeine is an effective regimen for maintaining performance levels at levels equal to those of a rested state despite excessive sleeplessness.
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