TABLE 2.

Sleep Disturbance, Daytime Symptoms, and Functional Performance: Pearson Correlations

Variable		1	2	3	4	5	6	7	8
Sleep disturbance
1. IS	Insomnia severity	1.00
2. PSQI	Sleep quality	.69	1.00
3. RDI	Respiratory disturbance	−.18	−.07	1.00
Daytime symptoms
4. GFI	Fatigue	.40	.47	−.05	1.00
5. ESS	Daytime sleepiness	.17	.24	.17	.27	1.00
6. CESD	Depressive symptoms	.45	.49	−.13	.55	.19	1.00
Functional performance
7. PF (SF-36)	Physical function	−.27	−.33	−.09	−.50	−.28	−.34	1.00
8. 6MWT	Walk test	−.11	−.22	−.02	−.26	−.14	−.13	.47	1.00

Note. N = 173. 6MWT = Six-Minute Walk Test; CESD = Center for Epidemiologic Studies of Depression Scale; ESS = Epworth Sleepiness Scale; GFI = Global Fatigue Index; IS = Insomnia Symptoms—Sleep Habits Questionnaire; PF (SF-36) = Physical Function—Medical Outcomes Studies Short Form-36; PSQI = Pittsburgh Sleep Quality Index; RDI = Respiratory Disturbance Index.