Norbert Luks

Performance impairment during four days partial sleep deprivation compared with the acute effects of alcohol and hypoxia

OBJECTIVE Subjects were exposed to cumulated partial sleep deprivation (psd), alcohol intake and hypoxia in a sequential design to examine the impact on neurobehavioral performance. METHODS Sixteen healthy male volunteers were enrolled in this study and were exposed in turn, after adaptation and baseline measurements, to one day of periods of hypoxia, one day of alcohol intake and one day for recovering (with 8h time in bed TIB). Subsequently the exposition of those conditions is that the subjects spent 5h night restriction daily for four consecutive days, followed by two recovery days. Performance was tested five (or six) times per day with reaction time task (SRT) and unstable tracking task (UTT). RESULTS The performance impairment showed to be cumulative in both tests over the four sleep deprivation days and differed significantly from baseline. Corresponding performance deficits under the influence of the stressors were for SRT: four days psd, 13% O(2) concentration and a blood alcohol concentration (BAC) of around 0.4-0.6 per thousand for UTT: four days psd, 13% O(2) concentration and a BAC of around 0.6 per thousand. One night of 8h sleep restored performance nearly to baseline level. CONCLUSIONS A sleeping time of 5h per night for four consecutive days impairs performance in such a way that traffic safety may be compromised.