Whole-body cold tolerance in older Korean female divers “haenyeo” during cold air exposure: effects of repetitive cold exposure and aging
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This study was conducted to investigate the effects of chronic and repetitive diving in cold sea water on physiological responses to cold in older Korean female divers, Haenyeo, who have been exposed to cold water through breath-hold diving since their teens. Young and older females, who have no experience of swimming in cold sea water, were recruited as control groups: older haenyeos (N = 10, 70 ± 3 years of age), young non-diving females (N = 10, 23 ± 2 years), and older non-diving females (N = 6, 73 ± 4 years). For the test of cold exposure, all subjects were exposed to cold in an air temperature of 12 °C with 45% RH in a sitting position for 60 min. The changes in core temperature showed no significant differences between older haenyeos and the other two groups. The decreases in mean skin temperature were greater for older haenyeos than the other two groups (P < 0.01). Older haenyeos had significantly lower energy expenditure during cold exposure when compared to older non-diving females (P < 0.05). Heart rate was significantly lower in older haenyeos than that of young non-diving females (P < 0.05). Older haenyeos felt cooler at the face with lower face temperature when compared with older non-diving females. The results indicate that older haenyeos respond to cold through reducing heat loss from the skin rather than increasing metabolic rate. These responses are distinctive features from the cold defensive system of young or older non-diving females.
KeywordsHaenyeo Cold tolerance Core body temperature Aging Breath-hold diving
Conflicts of interest
The authors declare that they have no conflicts of interest.
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2014 R1A2A2A03006522), by the research program of Korea Institute of Oriental Medicine (No. K17092), and by the Bio & Medical Technology Development Program of the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, and Future Planning (NRF-2014M3A9D7034335).
Compliance with ethical standards
The Institutional Review Board of Seoul National University approved the experimental procedure (IRB No. 1502/001-011).
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