Dynamic Adaptation of the Peripheral Circulation to Cold Exposure

Abstract

Humans residing or working in cold environments exhibit a stronger cold-induced vasodilation (CIVD) reaction in the peripheral microvasculature than those living in warm regions of the world, leading to a general assumption that thermal responses to local cold exposure can be systematically improved by natural acclimatization or specific acclimation. However, it remains unclear whether this improved tolerance is actually due to systematic acclimatization, or alternately due to the genetic predisposition or self-selection for such occupations. Longitudinal studies of repeated extremity exposure to cold demonstrate only ambiguous adaptive responses. In field studies, general cold acclimation may lead to increased sympathetic activity that results in reduced finger blood flow. Laboratory studies offer more control over confounding parameters, but in most studies, no consistent changes in peripheral blood flow occur even after repeated exposure for several weeks. Most studies are performed on a limited amount of subjects only, and the variability of the CIVD response demands more subjects to obtain significant results. This review systematically surveys the trainability of CIVD, concluding that repeated local cold exposure does not alter circulatory dynamics in the peripheries, and that humans remain at risk of cold injuries even after extended stays in cold environments.

Acute Effects of Normobaric Hypoxia on Hand-Temperature Responses During and After Local Cold Stress

“…Meeuwsen et al, (2009) had also detected no changes in almost all CIVD parameters, except that the DT was diminished during the hypoxic cold-water hand immersion. As recently discussed (Cheung and Daanen, 2012), there is a lack of consensus in the literature on the definition of CIVD, and hence on how to quantify this response. In the present study, the CIVD response was explored by determining a number of parameters, namely Tavg, N, Tmin, Tmax, DT, and Dt; among them, only the Tmax was slightly reduced during the HYPO CWI phase.…”

“…In the present study, the CIVD response was explored by determining a number of parameters, namely Tavg, N, Tmin, Tmax, DT, and Dt; among them, only the Tmax was slightly reduced during the HYPO CWI phase. Although the CIVD constitutes a complex physiological response and the impact of each parameter cannot be determined separately, the data of acclimatization/ habituation studies (Cheung and Daanen, 2012) suggest that, in terms of its cryoprotective function (Daanen and van der Struijs, 2005;Mathew et al, 1974), it is the increased perfusion-induced elevation in Tavg that constitutes the most decisive parameter during local cooling (cf. Amon et al, 2012;Keramidas et al, 2010).…”

Thermal stress, human performance, and physical employment standards

“…The evidence for physiological adaptations from longitudinal cold exposure is equivocal (Launay and Savourey 2009), with the dominant adaptation a perceptual habituation and desensitization to cold stress rather than large-scale systemic physiological changes as seen with heat acclimatization. Despite population and longitudinal evidence of cold adaptation in the extremities through greater local blood flow and digit skin temperatures, this has largely not been observed in laboratory acclimation studies (Cheung and Daanen 2012).…”

Relationships of self-identified cold tolerance and cold-induced vasodilatation in the finger

“…It is supported by recent reports such as effects of heat acclimatization (Lee at al. 2013a), ethnicity (Maley et al 2014), caffeine intake (Kim et al 2013), and trainability (Daanen et al 2012) on CIVD. Also, several attempts were conducted to explore relationships between cold acclimation and human brown fat by the development of PET-CT scanning (van der Lans et al 2013).…”