Table 1. Participant demographic, sleep, caloric, and light characteristics.
| Variable | N | Mean (Stdev) or N (%) |
| Sample characteristics | ||
| Age (years) | 54 | 30.6 (11.7) |
| Sex | 54 | 26 M 28 F |
| BMI | 52 | 24.0 (4.2) |
| Daily caloric intake | 54 | 2015 (545) |
| White N (%) | 54 | 40 (74) |
| Season N (%) | 54 | |
| Winter | 13 (24) | |
| Spring | 14 (26) | |
| Summer | 11 (20) | |
| Fall | 16 (29) | |
| Actigraphy Variables | ||
| Sleep start (hh:mm) | 54 | 01∶26 (2∶03) |
| Sleep end (hh:mm) | 54 | 8∶49 (2∶14) |
| Sleep duration (minutes) | 54 | 375 (54) |
| Sleep midpoint (hh:mm) | 54 | 05∶12 (2∶14) |
| Activity level (arbitrary units) | 54 | 323,582 (96,510) |
| Light Variables | ||
| Number of days | 54 | 6.2 (0.77, range 5–9) |
| Time above threshold (TAT) 100 lux (hours) | 54 | 4.3 (2.5) |
| Time above threshold (TAT) 500 lux (hours) | 54 | 1.4 (1.3) |
| Time above threshold (TAT) 1000 lux (hours) | 54 | 1.0 (1.1) |
| Mean Light Timing (MLiT100) above 100 lux (hh:mm) | 53 | 13∶56 (01∶20) |
| Mean Light Timing (MLiT500) above 500 lux (hh:mm) | 51 | 13∶05 (1∶46) |
| Mean Light Timing (MLiT1000) above 1000 lux (hh:mm) | 44 | 13∶26 (01∶17) |
| Standard Deviation MLiT100 (hours) | 53 | 04.42 (2.5) |
| Standard Deviation MLiT500 (hours) | 51 | 01.49 (1.3) |
| Standard Deviation MLiT1000 (hours) | 44 | 01.24 (1.09) |