Sex difference in blood pressure response to orthostatic stress: effects of transcutaneous electrical nerve stimulation

Abstract

Objective We investigated sex differences in blood pressure (BP) response to transcutaneous electrical nerve stimulation (TENS) during orthostatic stress (ORT). Methods Seventeen healthy young adults (males = 9; females = 8) underwent TENS or SHAM stimulus applied in the cervicothoracic region for 30 min in the supine position followed by 10 min in the orthostatic position. Electrocardiogram and BP were continuously recorded at rest and during ORT. Stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR) were calculated from the BP signal. Results Orthostatic challenge decreased BP similarly for both sexes during ORT, a deeper drop in CO and a slight increase in heart rate were found in women compared with men (P = 0.03 and 0.05, respectively). TENS evoked a pronounced fall in SBP in men compared with the SHAM condition (P < 0.05). TENS has no effect on SBP in women compared with the SHAM condition. Conclusion This finding suggests a possible modulatory effect by one cervicothoracic TENS session on sympathetic tonus in healthy men.