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Table 4 School Summer Differences in Growth, Sleep, and Energy Balance Related Outcomes

From: Later sleep timing predicts accelerated summer weight gain among elementary school children: a prospective observational study

Dependent Variable

School-Year

Mean (SD)

Summer Holiday

Mean (SD)

Significance Level

(p value)a

BMI Change

0.28 (0.66)

0.39 (0.77)

0.27

Sleep Midpoint (hrs.)

2:17 AM (0.65)

3:44 AM (1.44)

<  0.001

Total Sleep Time (hrs.)

7.86 (0.50)

7.66 (0.67)

0.002

Variability Sleep Midpointb (min.)

51.0 (30.5)

53.5 (40.6)

0.580

Exposure to Outdoor Lightc (hrs.)

1.02 (0.49)

0.89(0.52)

0.045

Sedentary Behavior (min.)

446.5 (69.3)

478.6 (100.0)

0.002

Light PA (min.)

361.9 (49.6)

304.7 (78.4)

<  0.001

Moderate to Vigorous PA (min.)

67.86 (26.1)

60.06 (30.5)

0.010

  1. aSignificance level was set at p < .006 to control for multiple testing across these 8 variables of interest
  2. bRoot Mean Square of Successive Differences of Sleep Midpoint
  3. cOutdoor light exposure defined as 60 s epochs with ambient light exposure > 240 lx