Heat acclimation enhances the cold-induced vasodilation response

Abstract

Purpose It has been reported that the cold-induced vasodilation (CIVD) response can be trained using either regular local cold stimulation or exercise training. The present study investigated whether repeated exposure to environmental stressors, known to improve aerobic performance (heat and/or hypoxia), could also provide benefit to the CIVD response. Methods Forty male participants undertook three 10-day acclimation protocols including daily exercise training: heat acclimation (HeA; daily exercise training at an ambient temperature, Ta = 35 °C), combined heat and hypoxic acclimation (HeA/HypA; daily exercise training at Ta = 35 °C, while confined to a simulated altitude of ~ 4000 m) and exercise training in normoxic thermoneutral conditions (NorEx; no environmental stressors). To observe potential effects of the local acclimation on the CIVD response, participants additionally immersed their hand in warm water (35 °C) daily during the HeA/HypA and NorEx. Before and after the acclimation protocols, participants completed hand immersions in cold water (8 °C) for 30 min, followed by 15-min recovery phases. The temperature was measured in each finger. Results Following the HeA protocol, the average temperature of all five fingers was higher during immersion (from 13.9 ± 2.4 to 15.5 ± 2.5 °C; p = 0.04) and recovery (from 22.2 ± 4.0 to 25.9 ± 4.9 °C; p = 0.02). The HeA/HypA and NorEx protocols did not enhance the CIVD response. Conclusion Whole-body heat acclimation increased the finger vasodilatory response during cold-water immersion, and enhanced the rewarming rate of the hand, thus potentially contributing to improved local cold tolerance. Daily hand immersion in warm water for 10 days during HeA/Hyp and NorEx, did not contribute to any changes in the CIVD response.

Central versus peripheral mechanisms of cold-induced vasodilation: a study in the fingers and toes of people with paraplegia

“…As discussed above, the observed skin temperature fluctuations in individuals with paraplegia may have been initiated by nonthermal factors (e.g., bladder stretching), thus confounding our ability to discern the origin of the responses. In this sense, our results favor a central origin of the CIVD response (Flouris and Cheung 2009a , b , 2010 ; Flouris et al 2008 ; Mekjavic et al 2008 ), which was recently supported by a study showing that whole-body heat acclimation can augment the CIVD response, whereas daily immersion of the hand in warm water does not (Ciuha et al 2021 ). Conducting a similar study with paraplegic participants, namely comparing the CIVD responses after heat acclimation with those observed after daily immersions of the hands and feet in warm water, may help to further confirm the contribution of central and peripheral factors in the regulation of digit skin blood flow in paraplegic participants.…”

Preliminary study of finger temperature recovery in patients with diabetes mellitus following cold stimulation

“…The local cold stimulation test has often been used to evaluate cold tolerance by observing the cold‐induced vasodilation after cooling 11,19 or to determine changes in microcirculatory function by assessing skin rewarming following cold stimulation 20 . Furthermore, it was used to diagnose Raynaud's response 21 .…”

Cardiovascular Stress and Characteristics of Cold-Induced Vasodilation in Women and Men during Cold-Water Immersion: A Randomized Control Study

“…For this reason, it has been hypothesized that CIVD may act as a protective mechanism to reduce the risk of cold injury in the limbs [5,[11][12][13]. In this light, some authors support the notion that CIVD reactions are driven by central mechanisms caused by an increase in deep body temperature [3,4,14,15] while others suggest that it may emerge as a response to peripheral stimuli in which arteriovenous anastomoses play a key role [8,16,17]. Despite the plethora of studies conducted on CIVD, the triggering mechanism of this phenomenon remains unclear, and its appearance has been described as nonsystematic and highly heterogenous [12,18].…”