CAFFEINE REVERSAL OF SLEEP-DEPRIVATION EFFECTS ON ALERTNESS AND MOOD

This study assessed the ability of high doses of caffeine to reverse c hanges in alertness and mood produced by prolonged sleep deprivation. Fifty healthy, nonsmoking males between the ages of 18 and 32 served a s volunteers. Following 49 h without sleep, caffeine (0, 150, 300, or 600 mg/70 kg, PO) was administered in a double-blind fashion. Measures of alertness were obtained with sleep-onset tests, the Stanford Sleep iness Scale (SSS), and Visual Analog Scales (VAS). Sleep deprivation d ecreased onset to sleep from a rested average of 19.9 min to 7 min. Fo llowing the highest dose of caffeine tested, sleep onset averaged just over 10 min; sleep onset for the placebo group averaged 5 min. Scores on the SSS increased from a rested mean of 1.6-4.8 after sleep depriv ation. Caffeine reduced this score to near rested values. Caffeine rev ersed sleep deprivation-induced changes in three subscales of the POMS (vigor, fatigue, and confusion) and produced values close to fully re sted conditions on several VAS. Serum caffeine concentrations peaked 9 0 min after ingestion and remained elevated for 12 h. This study showe d that caffeine was able to produce significant alerting and long-last ing beneficial mood effects in individuals deprived of sleep for 48 h.