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.