Abstract
Objectives: Many studies have been reported on adverse effects of sleep loss upon health. However, there are some discrepancies regarding the effect of sleep loss upon brain functions, and additionally, the study on the recovery process after sleep loss is insufficient. On the other hand, the study on the relationship between sleep and oxidative stress, which is related to many diseases, such as cancer, arteriosclerosis and depression, has been reported in recent years. It is useful to clarify the etiology of health disorders induced by sleep loss. Methods and Results: We investigated how subjective sleepiness, mood states, simple and cognitive performance changed after one night of sleep deprivation (SD). In another study, we investigated the change of several biological indicators after SD, 8-Hydroxy-deoxyguanosine (8-OH-dG), as an oxidative stress marker, and blood pressure and plasma cortisol. Subjective sleepiness nearly recovered to the baseline level on the 1st recovery day by 1 ordinary recovery sleep (7 hours) opportunities. Moods of fatigue and confusion, and high cognitive function seemed to need more than 2 ordinary recovery sleep opportunities to return to the baseline. A significant decrease of plasma cortisol at 7 AM and a slight but no significant increase of blood pressure, and no significant change of the urinary 8-OH-dG level after SD were observed. Conclusion: These results suggest that the recovery process after SD may differ among subjective sleepiness, mood and cognitive function, and 2 recovery sleep opportunities may be needed for the recovery of fatigue and high cognitive functions, and also circadian rhythm may disturbed after SD. It's necessary in the occupational safety and health to consider the prolonged adverse effect due to sleep loss.
