TABLE 2.

Adjusted relative difference in pre-condition versus post change in heart rate (HR) and heart rate variability (HRV) between control and flight.

Outcome	N	Control∗	Flight∗	Relative difference (95% C.I.)	p-value
HR	34	−3.6%	0.3%	3.9 (2.1, 5.8)	<0.0001
RMSSD	34	13.2%	2.6%	−10.6 (−21.3, 0.05)	0.0511
SDNN	34	13.3%	12.3%	−1.0 (−12.3, 10.2)	0.8576
HF	34	24.9%	7.6%	−17.3 (−42.0, 7.4)	0.1691
LF	34	50.2%	38.7%	−11.5 (−40.5, 17.4)	0.4351

HF, high-frequency power; LF, low-frequency power; RMSSD, root mean square of successive R-R interval differences; SDNN, the standard deviation of normal-to-normal intervals. ^∗Estimates represent the percent change in outcome from pre-condition to post-condition. Relative difference is the difference between those two values, flight – control. Associations are adjusted for diurnal variation, chamber effect, and a fixed effect for each participant.