Table 1. Items and factor loadings of the Sleep Hygiene Index (SHI).

Item Content	Factor Loadings
	Factor 1	Factor 2	Factor 3	Factor 4
1. I take daytime naps lasting two or more hours			.56
2. I go to bed at different times from day to day		.46
3. I get out of bed at different times from day to day		.40
4. I exercise to the point of sweating within 1 h of going to bed			.31
5. I stay in bed longer than I should two or three times a week		.78
6. I use alcohol, tobacco, or caffeine within 4 h of going to bed or after going to bed			.44
7. I do something that may wake me up before bedtime		.43
8. I go to bed feeling stressed, angry, upset, or nervous	.68
9. I use my bed for things other than sleeping	.68
10. I sleep on an uncomfortable bed				.66
11. I sleep in an uncomfortable bedroom				.70
12. I do important work before bedtime	.65
13. I think, plan, or worry when I am in bed	.70

All items were reverse coded, with higher scores indicating better sleep hygiene.