Body posture affects electroencephalographic activity and psychomotor vigilance task performance in sleep-deprived subjects.

OBJECTIVE: This study examined the effects of posture on electroencephalographic (EEG) activity and psychomotor vigilance task (PVT) performance in 16 sleep-deprived volunteers. METHODS: EEG data were collected while participants completed 10 min PVTs under two counterbalanced sitting/standing conditions during 28 h of continuous wakefulness. RESULTS: In both the sitting and standing conditions, theta activity progressively increased as a function of sleep loss, but standing upright significantly attenuated this effect, suggesting that alertness was improved by the more upright posture. The PVT results showed that cognitive psychomotor performance was maintained at nearly well-rested levels by standing upright, whereas reaction time and attention noticeably deteriorated when participants were seated. CONCLUSIONS: These results suggest that an upright posture increases EEG arousal and sustained attention, indicating that postural manipulations can be useful for counteracting fatigue in sleep-deprived individuals.