Cardiovascular responses to orthostasis during a simulated 3-day heatwave.

Autor: Fisher JT; Jozef Stefan International Postgraduate School, Ljubljana, Slovenia.; Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Jamova Cesta 39, SI-1000, Ljubljana, Slovenia., Ciuha U; Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Jamova Cesta 39, SI-1000, Ljubljana, Slovenia., Ioannou LG; Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Jamova Cesta 39, SI-1000, Ljubljana, Slovenia., Simpson LL; Division of Performance Physiology and Prevention, Department of Sports Science, University of Innsbruck, Innsbruck, Austria., Possnig C; Division of Performance Physiology and Prevention, Department of Sports Science, University of Innsbruck, Innsbruck, Austria., Lawley J; Division of Performance Physiology and Prevention, Department of Sports Science, University of Innsbruck, Innsbruck, Austria.; Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy., Mekjavic IB; Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Jamova Cesta 39, SI-1000, Ljubljana, Slovenia. igor.mekjavic@ijs.si.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2022 Nov 21; Vol. 12 (1), pp. 19998. Date of Electronic Publication: 2022 Nov 21.
DOI: 10.1038/s41598-022-24216-3
Abstrakt: Global warming has caused an increase in the frequency, duration, and intensity of summer heatwaves (HWs). Prolonged exposure to hot environments and orthostasis may cause conflicting demands of thermoregulation and blood pressure regulation on the vasomotor system, potentially contributing to cardiovascular complications and occupational heat strain. This study assessed cardiovascular and skin blood flow (SkBF) responses to orthostasis before, during and after a 3-day simulated HW. Seven male participants maintained a standard work/rest schedule for nine consecutive days split into three 3-day parts; thermoneutral pre-HW (25.4 °C), simulated HW (35.4 °C), thermoneutral post-HW. Gastrointestinal (T gi ) and skin (T sk ) temperatures, cardiovascular responses, and SkBF were monitored during 10-min supine and 10-min 60° head-up tilt (HUT). SkBF, indexed using proximal-distal skin temperature gradient (∆Tsk P-D ), was validated using Laser-Doppler Flowmetry (LDF). The HW significantly increased heart rate, cardiac output and SkBF of the leg in supine; HUT increased SkBF of the arm and leg, and significantly affected all cardiovascular variables besides cardiac output. Significant regional differences in SkBF presented between the arm and leg in all conditions; the arm displaying vasodilation throughout, while the leg vasoconstricted in non-HW before shifting to vasodilation in the HW. Additionally, ∆Tsk P-D strongly correlated with LDF (r = -.78, p < 0.001). Prolonged HW exposure and orthostasis, individually, elicited significant changes in cardiovascular and SkBF variables. Additionally, varying regional blood flow responses were observed, suggesting the upper and lower vasculature receives differing vasomotor control. Combined cardiovascular alterations and shifts towards vasodilation indicate an increased challenge to industrial workers during HWs.
(© 2022. The Author(s).)
Databáze: MEDLINE
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