Table 3.
Effect of activity monitor removals during sleep on the prediction of physical activity and total energy expenditure.
| Physical Activity | ||||
| counts·min-1·day-1 | log (counts·min-1·day-1) | |||
| Simulation | Mean (SD) | CV (%) | Mean (SD) | CV (%) |
| 24 HR | 228.4 (97.2) | - | 5.35 (0.40) | - |
| A1 | 220.5 (97.6)* | 3.1 | 5.30 (0.45)* | 0.7 |
| B1 | 332.9 (151.3)* | 26.0 | 5.71 (0.43)* | 4.8 |
| C1 | 228.2 (98.8) | 1.6 | 5.35 (0.42) | 0.3 |
| Total Energy Expenditure | ||||
| MJ·day-1 | log (MJ·day-1) | |||
| Simulation | Mean (SD) | CV (%) | Mean (SD) | CV (%) |
| 24 HR | 11.2 (3.3) | - | 2.38 (0.29) | - |
| A1 | 11.2 (2.8) | 9.0 | 2.37 (0.24) | 4.1 |
| B1 | 11.8 (4.2) | 9.9 | 2.41 (0.26) | 4.0 |
| C1 | 11.2 (2.9) | 9.0 | 2.38 (0.24) | 4.0 |
*p < 0.05 vs. 24 HR
24 HR: physical activity data from subset of highly adherent subjects (n = 35). Simulation A1: simulation of activity monitor removal during sleep by imputing zeroes. Simulation B1: simulation of compensating for activity monitor removal during sleep by measuring waking hours only (sleeping physical activity deleted). Simulation C1: simulation of compensating for activity monitor removal during sleep by imputing a constant (23.1 counts/min) CV(%)= coefficient of variation = ((standard deviation of 24 HR – Simulation A1/B1/C1)/(mean of 24 HR and Simulation A1/B1/C1)) × 100.