Sleep polysomnography and reported stress across 6 weeks

Despite the common notion that stress impairs sleep there is little published data showing that sleep (polysomnography (PSG)) is impaired across several sleep episodes in individuals who complain of daily stress during the same period. The present paper aimed at investigating such a connection. 33 subjects had 3 sleeps recorded with PSG at home across 6 weeks and kept a sleep/wake diary each day, including 3-hourly ratings of stress (scale 1-9). The stress ratings and the conventional PSG parameters were averaged across time. A stepwise multiple regression analysis showed that the best predictors of stress were Stage 1 sleep (beta = 0.49), latency to Stage 1 sleep (0.47) (adjusted for anxiety and age). Other sleep continuity variables had significant correlations with stress (reversed) but did not enter the multiple regression analysis. The correlation between stress before the start of the study and PSG data was not significant. It was concluded that moderately increased stress over a longer period of time is related to moderate signs of disturbed sleep during that period. This may be of importance when considering stress as a work environment problem.