Table 2 Correlation of daily activity-based or sleep-based physiological metrics and gestational age in days.

Resting heart rate

72.33

−0.051

−0.056 to −0.046

1.00E-84

RMSSD

17.35

0.12

0.10–0.13

2.46E-79

Heart rate average

76.24

−0.038

−0.043 to −0.033

1.72E-50

Sleep efficiency

106.83

−0.072

−0.082 to −0.062

2.11E-44

Total sleep

36653

−21.77

−27.74 to −15.79

1.04E-12

REM

11067

−10.87

−13.90 to −7.83

2.49E-12

Inactive

269.78

0.70

0.49–0.90

2.38E-11

Respiratory rate

18.34

−0.0023

−0.0030 to −0.0015

3.81E-09

MET medium

172.77

−0.28

−0.39 to −0.17

1.50E-06

Calories active

363.33

−0.53

−0.75 to −0.31

2.84E-06

Daily movement

9232

−9.59

−13.81 to −5.36

8.83E-06

Bed start

−3515

16.67

9.17–24.17

1.34E-05

Medium activity

46.00

−0.07

−0.11 to −0.04

1.35E-05

Bed end

32603

14.49

7.78–21.20

2.36E-05

Deep sleep

2209

5.19

2.74–7.63

3.27E-05

MET inactive

8.77

−0.012

−0.017 to −0.006

5.08E-05

Temp deviation

−0.19

0.0005

0.0003–0.0007

5.23E-05

Caloric expenditure

1534.5

−0.57

−0.86 to −0.27

0.000151

Low activity

278.96

−0.20

−0.34 to −0.07

0.003146

MET

1.43

−0.00024

−0.00041 to −0.00007

0.006786

MET high

40.22

−0.08

−0.14 to −0.02

0.007032

Steps

8456.8

−5.47

−9.62 to −1.32

0.009766

Rest time

636.7

−0.21

−0.38 to −0.05

0.012659

High activity

4.70

−0.01

−0.02 to −0.0017

0.017516

MET low

196.97

−0.09

−0.19–0.01

0.067587

Non-wear time

230.74

−0.22

−0.54–0.11

0.196156

Temperature trend

−0.03

−0.00009

−0.00025–0.00008

0.311622

Restless sleep

24.34

0.0045

−0.0043–0.0132

0.320527

Sleep midpoint

18407.8

−1.18

−5.09–2.74

0.555642

Sleep onset

1096.21

−0.14

−1.13–0.86

0.790827