Radial Pressure Pulse and Heart Rate Variability in Heat- and Cold-Stressed Humans

Table 1

The experimental variables after 45°C and 7°C water immersion.

	Heating experiment			Cooling experiment
	Control-1	45°C	𝑃-value	Control-2	7°C	𝑃-value
HR, beats/min	70.3±10.5	69.5±9.8	.157	65.9±9.8	66.6±10.2	.343
S_P, mmHg	111.6±6.9	110.7±7.7	.263	110.0±9.2	113.8±9.4	2.21𝐸−5 **
D_P, mmHg	69.8±6.7	68.8±7.0	.132	69.8±6.5	73.6±5.9	9.93𝐸−7 **
L_H temp, °C	34.8±1.8^‡	36.0±1.4	1.09𝐸−9 **	34.9±1.7	31.6±1.3	1.84𝐸−24 **
R_H temp, °C	35.3±1.6^‡	34.8±1.7	1.82𝐸−4 **	34.9±1.8	34.2±2.0	1.77𝐸−5 **
HRV, LF	791.46±1117.96	684.59±599.50	.4314	785.04±793.48	883.84±1003.82	.334
HRV, HF	1190.56±2490.21	1056.77±1519.63	.443	1081.99±1394.05	1383.35±2329.98	.066
HRV, LF/HF	1.64±2.16	1.70±2.02	.793	1.79±2.27	1.42±1.94	.076
HRV, HF%	0.51±0.20	0.51±0.23	.763	0.51±0.23	0.55±0.21	.033*
SE, 0–10 Hz	2.50𝐸−09±1.07	2.56𝐸−09±1.19	.669	2.69𝐸−09±1.22	2.36𝐸−09±1.61	.054
SE, 10–50 Hz	7.51𝐸−12±5.91	11.01𝐸−12±7.58	4.05𝐸−5 **	10.40𝐸−12±8.10	7.28𝐸−12±7.16	.005**
p1, mmHg	35.98±7.67	36.92±8.75	.384	37.63±9.51	34.43±11.55	.012*
p2, mmHg	18.9±5.82	18.37±6.33	.483	19.82±5.66	19.72±7.58	.904
p3, mmHg	14.98±4.74	14.61±5.2	.534	16.11±4.92	15.81±6.81	.670
AIr, %	53.05±14.08	50.31±14.4	.046*	53.87±14.27	58.88±15.77	3.74𝐸−4 **
DAI, %	41.94±10.65	39.37±8.85	.028*	43.07±8.92	46.33±12.52	.011*

Values are means ± SD (𝑛=60). HR: heart rate; S_P: systolic pressure; D_P: diastolic pressure; L_H temp: left-hand temperature; R_H temp: right-hand temperature; SE: Spectral energy. ‡: left-hand temperature versus right-hand temperature in baseline control and 𝑃<.01; *𝑃<.05 compared with the control for each experiment; **𝑃<.01 compared with the control for each experiment. p1: systolic pressure, p2: late systolic pressure, p3: early diastolic pressure.