Table 5.

HRV data from Fitbit device.

	Mean (SD) at baseline pre HRV-B phase	Mean SD at post HRV-B phase	P value for paired difference between post HRV-B and baseline	Effect Size (Cohen’s d)
Fitbit RMSSD summaries	34.2 (19.6)	40.9 (29.4)	0.048	0.27
Fitbit sleeping resting HR	67.8 (6.5)	67.7 (5.9)	0.898	0.02
Fitbit NREM HR	66.6 (7.6)	66.1 (7.1)	0.542	0.07
Fitbit overall sleep score	76.8 (4.7)	76.3 (5.1)	0.848	0.10
Fitbit composition score	20.1 (1.2)	19.7 (1.0)	0.414	0.37
Fitbit revitalisation score	19.2 (1.9)	18.7 (2.5)	0.339	0.22
Fitbit sleep duration score	37.5 (3.2)	37.9 (2.9)	0.685	0.13
Fitbit deep sleep score	72.1 (22.1)	69.2 (16.6)	0.191	0.15

Abbreviations: HR, heart rate; NREM, non-rapid eye movement; RMSSD, Root Mean Square of Successive Differences between heartbeats.