Dim light, sleep tight, and wake up bright – Sleep optimization in athletes by means of light regulation

Figures & data

Table I. Results obtained from the dataset including nights with regular sleep-wake patterns (SW30, N = 8).

	No-light regulation		Light regulation		Results of statistical analysis
	M	SD	M	SD	Df^2	F	p	η^2p
Actigraphy-based
SOL (h:min)	0:12	0:11	0:16	0:23	7	.005	.944	.001
WASO (h:min)	1:02	0:25	1:02	0:27	7	.000	.995	.000
Fragmentation (%)	32.02	10.77	35.61	11.29	6^a	.175	.690	.028
TST (h:min)	7:24	0:51	7:10	0:44	6^a	3.148	.126	.344
SE (%)	83.53	5.96	81.27	6.71	6^a	.960	.365	.138
Diary-based
SOL (h:min)	0:34	0:27	0:17	0:10	7	14.641	.006	.677
WASO (h:min)	0:25	0:22	0:24	0:21	7	.023	.885	.003
TST (h:min)	7:41	0:40	7:52	0:39	7	1.533	.256	.180
SE (%)	89.19	8.18	91.25	7.96	7	1.508	.259	.177
Sleep Quality
Sleep Quality (1–10)	6.63	0.88	7.05	0.67	7	11.882	.011	.629
Refreshed (1–10)	6.20	1.15	6.38	1.32	7	3.933	.088	.360
KSS (1–9)	5.51	1.42	5.16	1.28	7	1.318	.289	.158

Note: ^aThe covariate “order” was significant and remained in the statistical model. SOL = sleep onset latency, WASO = wake after sleep onset, TST = total sleep time, SE = sleep efficiency, KSS = Karolinska Sleepiness Scale.

Table II. Results obtained from the dataset including irregular sleep-wake patterns (SW120, N = 25).

	No-light regulation		Light regulation		Results of statistical analysis
	M	SD	M	SD	Df^2	F	p	η^2p
Actigraphy-based
SOL (min)	0:16	0:20	0:11	0:13	21	3.362	.081	.138
WASO (min)	0:58	0:23	1:03	0:33	21	1.340	.260	.060
Fragmentation (%)	34.90	15.10	36.71	14.62	21	2.673	.117	.113
TST (h:min)	7:04	0:49	6:55	0:59	21	2.89	.104	.121
SE (%)	82.37	9.81	80.99	11.15	21	3.654	.070	.148
Diary-based
SOL (min)	0:24	0:20	0:16	0:09	22	5.984	.023	.214
WASO (min)	0:21	0:20	0:20	0:21	22	.000	.984	.000
TST (h:min)	7:40	0:45	7:42	0:53	22	.176	.679	.008
SE (%)	92.10	6.24	92.45	6.74	22	.123	.729	.006
Sleep Quality
Sleep Quality (1–10)	6.81	.83	6.95	.94	22	1.103	.305	.048
Refreshed (1–10)	6.37	1.01	6.43	1.06	22	.194	.664	.009
KSS (1–9)	4.90	1.38	4.75	1.1	22	.725	.404	.032

Note: SOL = sleep onset latency, WASO = wake after sleep onset, TST = total sleep time, SE = sleep efficiency, KSS = Karolinska Sleepiness Scale.

Table III. Process evaluation outcomes and list of identified symptoms.

	Light goggles	Amber glasses	Transparent glasses
Headache	2/26	0/26	0/26
Dizziness	1/26	0/26	0/26
Nausea	1/26	0/26	0/26
Eye irritation	3/26	1/26	2/26
Eye redness	0/26	0/26	0/26
Blurred vision	9/26	6/26	3/26
Light bothersome to eyes	5/26	1/26	1/26
Restlessness	1/26	1/26	0/26
Excessive energy	0/26	1/26	0/26
Irritability	0/26	1/26	1/26
Other:	6/26	4/26	4/26
	Looking down, showering, eating, moving, social activities, getting dressed, walking the stairs in the dark, seeing dots/stars, orientating in the dark, no depth vision	Dry eyes, showering, intimacy, reflections of light-sources in the dark, no sharp vision, eye lashes touched the glasses, tired eyes, reduced vision in dark places, getting tired more easily	Dry eyes, showering, intimacy
Appearance (1–10)	3.92 ± 2.17	4.12 ± 2.21	6.23 ± 1.66
Inconvenience during other activities	17/26	12/26	3/26
Reading (OK)	24/26	25/26	26/26
Distance vision (OK)	23/26	26/26	26/26