Table 2.

Heritability estimates of derived sleep variables from BOLT-REML

Sleep variable	h 2	95% CI
Sleep duration	0.190	0.182–0.198
Sleep duration variability (SD)	0.028	0.020–0.036
Number of nocturnal sleep episodes	0.223	0.215–0.231
Sleep efficiency	0.130	0.122–0.138
L5 timing	0.117	0.109–0.125
M10 timing	0.087	0.079–0.095
Sleep midpoint timing	0.101	0.093–0.109
Diurnal inactivity	0.148	0.134–0.161