Sleep quality but not sleep quantity effects on cortisol responses to acute psychosocial stress

Figures & data

Table 1. Categorization of PSQI item scores by gender (mean and SD given for raw data).

	Frequency
Item responses	Males	Females	X^2	M	SD
	PSQI global score		0.36	5.79	2.69
Good sleeper (≤5)	17	21
Bad sleeper (>5)	12	23
	Sleep quality		0.03	1.10	0.67
Good sleep quality (0)	5	7
Fairly good sleep quality (1)	17	26
Bad sleep quality (2, 3)	7	11
	Hours of sleep		0.61	6.88	1.09
7 h or above	16	28
6–6.99 h	8	9
0–5.99 h	5	7
	Trouble staying awake		0.12	0.56	0.73
No trouble (0)	17	24
At least some trouble (1, 2, 3)	12	20
	Keeping up enthusiasm		1.54	1.19	0.76
No problem (0)	5	6
A very slight problem (1)	18	23
Somewhat of a problem (2, 3)	6	15

All X² were non-significant.

Figure 1. Neither overall sleep assessed by global PSQI scores (A) nor hours of sleep (B) showed an effect on cortisol stress responses (mean, SE).

Figure 2. The impact of sleep quality (SQ) on cortisol stress responses in females (A) and males (B).

Table 2. Repeated-measures ANCOVAs testing gender-dependent sleep effects on cortisol stress responses (N = 73).

	Good/bad sleep		Hours of sleep		Sleep quality		Staying awake		Enthusiasm
	F	p	F	p	F	p	F	p	F	p
Between-subject effects
Gender	0.40	0.53	0.69	0.41	3.93	0.052	0.75	0.39	0.89	0.35
IV	0.12	0.73	0.12	0.89	2.06	0.14	1.82	0.18	2.09	0.13
IV × gender	0.01	0.75	0.81	0.45	4.07	0.022*	1.30	0.26	1.74	0.18
Within-subject effects
Cortisol	3.47	0.029*	3.16	0.040*	4.31	0.011*	2.82	0.055†	4.73	0.007*
Cortisol × gender	1.81	0.16	1.52	0.22	5.25	0.004*	2.34	0.092†	2.73	0.060†
Cortisol × IV	0.55	0.60	0.71	0.60	1.99	0.09†	2.67	0.065†	2.31	0.052†
Cortisol × IV × gender	0.90	0.42	0.54	0.73	2.71	0.025*	0.55	0.60	1.12	0.35

IV, independent variable.

†p ≤ 0.10; *p < 0.05.

Figure 3. Daytime dysfunctions: trouble staying awake (A) as well as problems keeping up enthusiasm (B) were associated with blunted cortisol stress responses.