Table 1.

Recommended sleep duration in adults [14].

Recommendation	Age group
	Young adults (18–25 years)	Adults (26–65 years)
(A) Low, not recommended	<6 h	<6 h
(B) Low, may be appropriate	6–7 h	6–7 h
(C) Recommended	7−9 h	7−9 h
(D) High, may be appropriate	10−11 h	9−10 h
(E) High, not recommended	>11 h	>10 h

Associations between variables were calculated using non-parametric rank correlations (Spearman's r_s). The level of statistical significance was set at two-tailed α=0.05.