Table 1: Comparison of time-domain heart rate variability parameters between the active periods
Active period*	Mean RR			SDNN †			RMSSD ‡
	Mean difference	p value		Mean difference	p value		Mean difference	p value
WBV vs LMWL	47.07	0.01		8.60	0.002		3.16	0.39
WBV vs HMWL	59.40	0.001		9.20	0.02		2.96	0.52
WBV vs WBV.LMWL	50.20	0.01		8.73	0.009		4.49	0.29
WBV vs WBV.HMWL	50.07	0.01		6.87	0.01		0.96	0.77
LMWL vs HMWL	12.33	0.41		0.60	0.85		-0.20	0.95
LMWL vs WBV.LMWL	3.13	0.82		0.13	0.93		1.33	0.66
LMWL vs WBV.HMWL	3.00	0.85		-1.73	0.50		-2.20	0.41
HMWL vs WVB.LMWL	-9.20	0.56		-0.47	0.90		1.53	0.44
HMWL vs WBV.HMWL	-9.33	0.54		-2.33	0.36		-2.00	0.38
WBV.LMWL vs WBV.HMWL	-0.13	0.99		-1.87	0.45		-3.53	0.12
*WBV: Whole-body vibration, LMWL: Low mental workload, HMWL: High mental workload †SDNN: SD of normal-to-normal intervals, ‡RMSSD: root mean square of the successive differences