Finger cold-induced vasodilation of older Korean female divers, haenyeo: effects of chronic cold exposure and aging

Abstract

The aim of the present study was to evaluate the local cold tolerance of older Korean female divers, haenyeo (N = 22) in terms of cold acclimatization and ageing. As control groups, older non-diving females (N = 25) and young females from a rural area (N = 15) and an urban area (N = 51) participated in this study. To evaluate local cold tolerance, finger cold-induced vasodilation (CIVD) during finger immersion of 4 °C water was examined. As a result, older haenyeos showed greater minimum finger temperature and recovery finger temperature than older non-diving females (P < 0.05), but similar responses in onset time, peak time, maximum finger temperature, frequency of CIVD, heart rate, blood pressure, and thermal and pain sensations as those of older non-diving females. Another novel finding was that young urban females showed more vulnerable responses to local cold in CIVD variables and subjective sensations when compared to older females, whereas young rural females had the most excellent cold tolerance in terms of maximum temperature and frequency of CIVD among the four groups (P < 0.05). The present results imply that older haenyeos still retain cold acclimatized features on the periphery even though they changed their cotton diving suits to wet suits in the early 1980s. However, cardiovascular responses and subjective sensations to cold reflect aging effects. In addition, we suggest that young people who have been adapted to highly insulated clothing and indoor heating systems in winter should be distinguished from young people who were exposed to less modern conveniences when compared to the aged in terms of cold tolerance.

Human cold habituation: Physiology, timeline, and modifiers

“…Perhaps not surprisingly, data in these older female divers suggest they no longer have the same general systemic thermoregulatory adaptations that were observed in the cotton suit wearing divers [ 90 ]. However, the wet suit wearing Korean divers may have developed a habituated, local vascular response, as they show greater minimum and recovery finger temperatures during a standardized cold water finger immersion [ 91 ]. Further examples of occupational cold water immersion can be found in Table 6 .…”

Low-frequency oscillations of finger skin blood flow during the initial stage of cold-induced vasodilation at different air temperatures

“…Arteriovenous anastomoses (AVAs) may be implicated in CIVD because CIVD mainly occurs where AVAs are abundant [ 4 ], and relaxation of AVAs leads to an increase in local blood flow and tissue temperature [ 5 ]. Differences in CIVD responses between people of different ages [ 6 – 8 ], people of different races [ 9 , 10 ], and different O 2 concentrations [ 11 ] and the effects of tobacco [ 12 ] and menthol activation [ 13 ] on CIVD responses have been investigated. In addition, some reviews of several potential mechanisms and models have been published [ 5 , 14 – 16 ].…”