Table 4.
Predicted Daily Means (95% CI) Moderate to Vigorous Physical Activity by Treatment Phase and Average Day Length for Each Season
| Fixed day lengtha /Treatment group | Baseline | Follow-up | Change from baseline to follow-up |
|---|---|---|---|
| 9.8 hours | |||
| Increase PA | 28.8 | 36.4 | 7.62 (3.10, 11.24) |
| Decrease SB | 28.8 | 31.5 | 2.65 (−0.81, 6.12) |
| Difference | 4.96 (0.20, 9.73) | ||
| 13.3 hours | |||
| Increase PA | 28.3 | 42.9 | 14.65 (12.27, 17.03) |
| Decrease SB | 28.3 | 30.1 | 1.87 (−0.55, 4.28) |
| Difference | 12.78 (9.47, 16.10) | ||
| 14.6 hours | |||
| Increase PA | 28.1 | 45.3 | 17.26 (14.08, 20.43) |
| Decrease SB | 28.1 | 29.6 | 1.57 (−1.70, 4.85) |
| Difference | 15.69 (11.26, 20.11) | ||
| 11.1 hours | |||
| Increase PA | 28.6 | 28.8 | 10.23 (7.57, 12.88) |
| Decrease SB | 28.6 | 31.0 | 2.36 ( 0.17, 4.90) |
| Difference | 7.87 (4.34, 11.39) | ||
| p-value for three-way tx by time by average day length interaction | 0.002 | ||
a
Average day length reported represents average day length for each seasonal period in Table 2. Continuous variable of average day length used in regression equation. Season not controlled for in analysis.
tx, treatment; PA, physical activity; SB, sedentary behavior