Table 3.

Self-assessment of sleep quality by work-shift and conditions

Factors	Elements	Conditions	Last day shift before a night shift	Night shift		First day shift after a night shift
			On waking (mean±SD)	On waking (mean±SD)	After a nap (mean±SD)	On waking (mean±SD)
I	Sleepiness on waking	Dark conditions	38.09±12.84	40.93±8.75	32.82±9.44	38.67±10.40
		Well-lit conditions	42.48±11.92	41.83±13.10	37.47±14.06	40.38±12.43
Ⅱ	Sleep induction and maintenance	Dark conditions	46.33±7.84*	46.11±7.41	37.95±9.45	46.55±9.86
		Well-lit conditions	52.13±9.94*	46.56±10.85	31.15±11.62	48.50±12.78
Ⅲ	Dreaming	Dark conditions	43.78±13.12	46.85±10.57	51.74±10.81	48.04±12.60
		Well-lit conditions	51.19±9.74	51.22±13.20	54.66±8.94	52.97±8.90
Ⅳ	Recovery from fatigue	Dark conditions	41.37±11.78	42.11±10.41	31.17±8.93	42.01±8.04
		Well-lit conditions	45.08±11.48	44.30±12.57	33.90±9.27	45.92±12.74
Ⅴ	Sleep duration	Dark conditions	41.92±7.99	47.82±9.83	28.45±7.54	43.15±8.63
		Well-lit conditions	40.04±13.33	42.64±11.12	30.28±8.79	41.88±9.54

*Difference between dark conditions and well-lit conditions p<0.1.