Objective: Endothelial function, the ability of cells of the vascular endothelial wall to secrete compounds, is linked with metabolic and cardiovascular disease risks. One of the most well-known noninvasive tests used to assess skin vascular reactivity as a measure of endothelial function is the reactive hyperemic response test (RHRT). However, there is lack of consensus regarding the impact of thermoregulation on endothelial (dys)function and the results from the RHRT. Thus, the aim of the present study was to investigate the impact of core temperature on cutaneous vascular reactivity, as assessed via the finger RHRT. Approach: Following a 15-minute baseline period, seven adults entered a water tank maintained at 42°C and passively rested in a semi-supine position. Thereafter, they entered a water tank maintained at 12°C. They were immersed until their rectal temperature (Tre) increased or decreased about 0.5°C above and below the baseline Tre respectively. This procedure was repeated twice and an occlusion was conducted during the baseline period and at the second repetition of water immersions. Main results: During the post-occlusion phase, skin blood flow (SkBF) was greater, comparing to pre- and occlusion phases, across all Tre levels (five levels: baseline, mild hyperthermia 1, mild hypothermia 1, mild hyperthermia 2, mild hypothermia 2). Also, SkBF throughout pre-occlusion, occlusion, and post-occlusion was greater during mild hyperthermia 2. Significance: We found a significant impact of core temperature on SkBF and cutaneous vascular reactivity which affects the diagnostic indicators obtained from the RHRT and can impact the final outcome.
Tsoutsoubi, Lydia; Ioannou, Leonidas G.; Cheung, Stephen S.; and Flouris, Andreas D.
"Influence of Core Temperature Changes During Whole-Body Warming and Cooling on Cutaneous Vascular Reactivity,"
Journal of Human Performance in Extreme Environments: Vol. 18
Available at: https://docs.lib.purdue.edu/jhpee/vol18/iss1/5