Sleep studies (n=32)
| Zurich 490 m | Davos Schatzalp 1860 m | Davos Jakobshorn 2590 m | |||
| 1st day | 1st day | 2nd day | 1st day | 2nd day | |
| Total sleep time (min) | 369 (345–388) | 423* (389–467) | 427* (405–458) | 391‡ (303–457) | 401†‡ (300–423) |
| Sleep efficiency (%) | 86 (80–89) | 82 (76–87) | 79* (72–88) | 78* (61–84) | 71*†‡ (61–84) |
| NREM 1+2 (%) | 74 (61–81) | 74 (61–85) | 74 (63–81) | 82* † ‡ (74–94) | 81* ‡ (69–93) |
| NREM 3+4 (%) | 14 (8–22) | 12 (4–19) | 14 (8–17) | 6* † ‡ (0–12) | 9* ‡ (2–16) |
| REM (%) | 13 (9–18) | 13 (10–18) | 13 (9–20) | 10 † ‡ (4–16) | 10 (7–15) |
| Arousal index (1/h) | 35.5 (25.1–43.2) | 41.8* (33.5–61.1) | 45.5* (29.9–56.7) | 51.3* (37.6–65.5) | 49.3* (34.4–65.7) |