Caffeine intake induced significant disruptions to a number of sleep indices including increased sleep onset latency ( caffeine 51.1 34.7 ; placebo 10.2 4.2 min ; p = 0.028 ) and decreased sleep efficiency ( caffeine 76.1 19.6 ; placebo 91.5 4.2 % ; p = 0.028 ) , rapid eye movement sleep ( caffeine 62.1 19.6 ; placebo 85.8 24.7 min ; p = 0.028 ) and total sleep time ( caffeine 391 97 ; placebo 464 49 min ; p = 0.028 ) .