Heart Rate Variability in Shift Workers: Responses to Orthostatism and Relationships with Anthropometry, Body Composition, and Blood Pressure

Table 2

Medians of heart rate variability (HRV) variables in the supine and orthostatic positions.

HRV variables	Supine position	Orthostatic position	value
	Median (p25, p75)	Median (p25, p75)
HR (bpm)	65.9 (59.7, 71.9)	82.3 (74.2, 90.2)	<0.0001
RMSSD (ms)	34.3 (23.9, 50.1)	19.9 (13.3, 30.1)	<0.0001
HF (ms²)	81.9 (35.7, 168.7)	26.1 (10.5, 62.1)	<0.0001
LF (ms²)	103.4 (60.8, 186.4)	120.6 (62.4, 224.1)	0.005
LF/HF	1.3 (0.7, 2.5)	4.7 (2.5, 7.9)	<0.0001

HRV: heart rate variability; HR: heart rate; RMSSD: root mean square of successive RR interval differences; HF: high frequency; LF: low frequency; LF/HF: ratio of low frequency and high frequency. Rawdata. The Wilcoxon test was made using log transformation values, but, for ease of interpretation, all medians (plus p25, p75) are given in the original units.