Neural Control of Blood Pressure is Altered Following Isolated Leg Heating in Aged Humans.

Neural Control of Blood Pressure is Altered Following Isolated Leg Heating in Aged Humans. Am J Physiol Heart Circ Physiol. 2020 Mar 06;: Authors: Engelland RE, Hemingway HW, Tomasco OG, Olivencia-Yurvati AH, Romero SA Abstract There is a sustained reduction in arterial blood pressure that occurs in aged adults following exposure to acute leg heating. We tested the hypothesis that acute leg heating would decrease arterial blood pressure in aged adults secondary to sympathoinhibition. Thirteen young and 10 aged adults were exposed to 45 min of leg heating. Muscle sympathetic nerve activity (radial nerve) was measured before leg heating (Pre-heat) and 30 min after (Recovery), and is expressed as burst frequency. Neurovascular transduction was examined by assessing the slope of the relation between muscle sympathetic nerve activity and leg vascular conductance measured at rest and during isometric handgrip exercise performed to fatigue. Arterial blood pressure was well maintained in young adults (Pre-heat, 86 ± 6 mmHg vs. Recovery, 88 ± 7 mmHg; P = 0.4) due to increased sympathetic nerve activity (Pre-heat, 16 ± 7 bursts min-1 vs. Recovery, 22 ± 10 bursts min-1; P < 0.01). However, in aged adults, sympathetic nerve activity did not differ from Pre-heat (37 ± 5 bursts min-1) to Recovery (33 ± 6 bursts min-1, P = 0.1), despite a marked reduction in arterial blood pressure (Pre-heat, 101 ± 7 mmHg vs. Recovery, 94 ± 6 mmHg; P <...
Source: American Journal of Physiology. Heart and Circulatory Physiology - Category: Physiology Authors: Tags: Am J Physiol Heart Circ Physiol Source Type: research