ACTIVITY AT HABITUAL SLEEP TIMES INTERFERES WITH PERFORMANCE

May, G. C., Fitzpatrick, P A., Cullen, S. J., Kelly, L., O'Hagan, A., & Warrington, G. D. (2011). An analysis of the impact of acute sleep deprivation on repeat cycling time trial performance. Medicine and Science in Sports and Exercise, 43(5). Supplement abstract 1023.

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This study evaluated the effects of acute sleep deprivation, over 24 hours, on a repeat cycling time-trial performance in trained male cyclists (N = 6). Ss were tested on three occasions all separated by seven days within a 21-day period. During the first test, Ss performed a maximal incremental test on an electromagnetically-braked cycle ergometer. Following a standardized recovery period, each S then completed a baseline 20-minute self-paced maximal performance test. Ss subsequently returned on two further occasions to perform two 24-hour trials. During the course of each 24-hour trial, Ss performed a total of four self-paced maximal performance tests at set times in either a sleep-deprived and or sleep-normal state following a randomized crossover design. The self-paced maximal performance tests were undertaken at 0, 8, 17, and 24 hours. During the sleep-deprived trial, Ss accrued no sleep, while during the sleep-normal trial they were allocated an 8-hour sleep period between 8 and 17 hours.

The sleep-normal condition resulted in a sleep duration of ~365 minutes. No significant differences were found across baseline trials for each of the three tests or for the mean cumulative distance covered over the four self-paced maximal performance tests between and within both conditions. Total distance covered decreased significantly between 8 and 17 hours in the sleep-deprived condition. No significant differences were observed across trials in the sleep-normal treatment.

Implication. Performance decreases during times when sleep habitually occurs (circadian rhythm) but over 24 hours, total performance is not compromised.

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