Est-il dangereux de dormir « moins » ou « plus » ?

Les deux, selon les résultats d'une étude incluant 10.308 fonctionnaires britanniques à col blanc, de 35-55 ans suivis pendant => 12 ans :

une diminution de la durée du sommeil chez les sujets dormant 6, 7 ou 8 heures lors de leur inclusion a été associée à un doublement de la mortalité cardio-vasculaire.

Mais une augmentation de la durée du sommeil parmi ceux qui dormaient initialement 7 ou 8 heures a été associée à un doublement de la mortalité non cardio-vasculaire.

Participants:

9,781 participants with complete data were included in the analyses at Phase 1, and 7,729 of the same participants were included in the analyses at Phase 3 and the analyses of change in sleep duration.

Interventions: None.

Measurements and Results:

U-shaped associations were observed between sleep (≤5, 6, 7, 8, ≥9 hours) at Phase 1 and Phase 3 and subsequent all-cause, cardiovascular, and non-cardiovascular mortality. A decrease in sleep duration among participants sleeping 6, 7, or 8 hours at baseline was associated with cardiovascular mortality, hazard ratio 2.4 (95% confidence intervals 1.4-4.1). However, an increase in sleep duration among those sleeping 7 or 8 hours at baseline was associated with non-cardiovascular mortality, hazard ratio 2.1 (1.4-3.1). Adjustment for the socio-demographic factors, existing morbidity, and health-related behaviours measured left these associations largely unchanged.

Conclusions:

This is the first study to show that both a decrease in sleep duration and an increase in sleep duration are associated with an increase in mortality via effects on cardiovascular death and non-cardiovascular death respectively.