Table 1. Cut-points for converting continuous variables collected by actigraphy to 4-level categorical variables consistent with the answer categories for the question on subjective sleep quality.

Categorical variable	Sleep onset latency, min	Efficiency	Wake after sleep onset, min
Very good sleeper	<15	>90%	<5
Fairly good sleeper	15–20	85–90%	5–15
Fairly bad sleeper	21–31	80–84%	16–30
Very bad sleeper	>31	<80%	>31