Table 4. Correlations between sleep variables (*p < 0.05, **p < 0.01).

Sleep variables	Nap duration		Nap end time
	r	p	r	p
Bedtime	0.38	0.006**	0.52	0.000**
Sleep onset time	0.37	0.008**	0.52	0.000**
Wake time	−0.06	0.662	0.37	0.007**
Sleep latency	0.02	0.905	0.08	0.576
Nighttime sleep duration	−0.57	0.000**	−0.31	0.028*
Nap duration	–	–	0.36	0.011*
Total sleep duration	0.21	0.141	−0.051	0.727
Nap end time	0.36	0.011*	–	–
Sleep efficiency	0.06	0.661	−0.15	0.284
WASO (wake after sleep outset)	−0.15	0.314	0.11	0.453