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Improvements in vascular function in response to acute lower limb heating in young healthy males and females

journal contribution
posted on 06.08.2021, 13:06 by Jem L Cheng, Jennifer S Williams, Sven HoekstraSven Hoekstra, Maureen J MacDonald
Regular exposure to passive heat stress improves vascular function, but the optimal heating prescription remains undefined. Local limb heating is more feasible than whole body heating, but the evidence demonstrating its efficacy is lacking. The purpose of this study was to determine whether acute improvements in vascular function can be achieved with lower limb heating in 16 young healthy individuals (8 female, 8 male). In separate visits, participants underwent 45 min of ankle- and knee-level hot water immersion (45?C). A subset of seven participants also participated in a time-control visit. Endothelial function was assessed through simultaneous brachial and superficial femoral artery flow-mediated dilation (FMD) tests. Macrovascular function was quantified by %FMD, whereas microvascular function was quantified by vascular conductance during reactive hyperemia. Arterial stiffness was assessed through carotid-femoral and femoral-foot pulse wave velocity (PWV). Plasma concentrations of interleukin-6 and extracellular heat shock protein-72 (eHSP72) were used as indicators of inflammation. Our findings showed that 45 min of lower limb heating—regardless of condition—acutely improved upper limb macrovascular endothelial function (i.e., brachial %FMD; Pre: 4.6 ± 1.7 vs. Post: 5.4 ± 2.0%; P = 0.004) and lower limb arterial stiffness (i.e., femoral-foot PWV; Pre: 8.4 ± 1.2 vs. Post: 7.7 ± 1.1 m/s; P = 0.011). However, only knee-level heating increased upper limb microvascular function (i.e., brachial peak vascular conductance; Pre: 6.3 ± 2.7 vs. Post: 7.8 ± 3.5 mL/min s² mmHg; P 0.050) and plasma eHSP72 concentration (Pre: 12.4 ± 9.4 vs. Post: 14.8 ± 9.8 ng/mL; P 0.050). These findings show that local lower limb heating acutely improves vascular function in younger individuals, with knee-level heating improving more outcome measures.
NEW & NOTEWORTHY This study demonstrates that lower limb hot water immersion is an effective strategy for acutely improving vascular function in young, healthy males and females, thereby encouraging the development of accessible modes of heat therapy for vascular health.

Funding

Natural Sciences and Engineering Research Council of Canada (NSERC DG #20011033)

NSERC Alexander Graham Bell Canada Graduate Scholarships

History

School

  • Sport, Exercise and Health Sciences

Published in

Journal of Applied Physiology

Volume

131

Issue

1

Pages

277 - 289

Publisher

American Physiological Society

Version

AM (Accepted Manuscript)

Rights holder

© American Physiological Society

Publisher statement

This paper was accepted for publication in the journal Journal of Applied Physiology and the definitive published version is available at https://doi.org/10.1152/japplphysiol.00630.2020

Acceptance date

14/05/2021

Publication date

2021-07-18

Copyright date

2021

ISSN

8750-7587

eISSN

1522-1601

Language

en

Depositor

Mr Sven Hoekstra. Deposit date: 2 August 2021