Table 2.

Subjective Sleep Quality (Mean ± SD)

Pittsburgh Sleep Quality Index Subscoresa	Treatment Group				Time		Time × Group		Group
	Red Light		Placebo		F1,18	P	F1,18	P	F1,18	P
	Preintervention	Postintervention	Preintervention	Postintervention
Sleep quality	1.80 ± 0.92	1.30 ± 0.48	1.90 ± 0.74	2.20 ± 0.63	0.42	.53	6.70	.02	3.24	.09
Sleep latency	1.80 ± 1.03	0.30 ± 0.48	0.70 ± 0.48	0.80 ± 0.42	0.31	.58	0.31	.58	5.65	.03
Sleep duration	0.30 ± 0.48	0.30 ± 0.48	0.70 ± 0.48	0.90 ± 0.57	2.25	.15	2.25	.15	5.36	.03
Habitual sleep efficiency	0.90 ± 0.57	0.40 ± 0.52	0.90 ± 0.57	1.00 ± 0.67	1.26	.28	2.84	.11	2.49	.13
Sleep disturbance	1.50 ± 0.97	0.90 ± 0.74	1.30 ± 0.95	1.40 ± 0.70	1.69	.21	3.32	.09	0.21	.65
Use of sleeping medications	0.00 ± 0.00	0.00 ± 0.00	0.00 ± 0.00	0.00 ± 0.00	NA	NA	NA	NA	NA	NA
Daytime dysfunction	6.60 ± 3.53	1.20 ± 0.63	2.00 ± 0.82	1.90 ± 0.74	6.40	.02	3.60	.07	2.15	.16

Abbreviation: NA, not applicable.^a Higher scores reflect worse sleep quality.