Time Course of Physiological and Psychological Responses in Humans during a 20-Day Severe-Cold–Acclimation Programme

• Published in: PloS one Vol. 9; no. 4; p. e94698
• Main Authors: Brazaitis, Marius, Eimantas, Nerijus, Daniuseviciute, Laura, Baranauskiene, Neringa, Skrodeniene, Erika, Skurvydas, Albertas
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.04.2014; Public Library of Science (PLoS)
• Subjects: Acclimation; Acclimatization; Acclimatization - physiology; Adaptation; Biology and Life Sciences; Biomarkers; Body mass; Body mass index; Body size; Body Temperature - physiology; Cold; Cold acclimation; Cold Temperature; Heart Rate - physiology; Heat; Humans; Hypotheses; Immune system; Immunity; Innate immunity; Male; Markers; Medical research; Medicine and Health Sciences; Metabolism; Non-shivering; Oxygen Consumption - physiology; Physiological aspects; Physiology; Psychological aspects; Shivering; Sport science; Stress concentration; Stress, Physiological - physiology; Stress, Psychological - physiopathology; Studies; Swimming; Temperature; Thermogenesis; Thermoregulation; Time Factors; Water immersion; Young Adult; Lithuania
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0094698

The time course of physiological and psychological markers during cold acclimation (CA) was explored. The experiment included 17 controlled (i.e., until the rectal temperature reached 35.5°C or 170 min had elapsed; for the CA-17 session, the subjects (n = 14) were immersed in water for the same amount of time as that used in the CA-1 session) head-out water immersions at a temperature of 14°C over 20 days. The data obtained in this study suggest that the subjects exhibited a thermoregulatory shift from peripheral-to-central to solely central input thermoregulation, as well as from shivering to non-shivering thermogenesis throughout the CA. In the first six CA sessions, a hypothermic type of acclimation was found; further CA (CA-7 to CA-16) led to a transitional shift to a hypothermic-insulative type of acclimation. Interestingly, when the subjects were immersed in water for the same time as that used in the CA-1 session (CA-17), the CA led to a hypothermic type of acclimation. The presence of a metabolic type of thermogenesis was evident only under thermoneutral conditions. Cold-water immersion decreased the concentration of cold-stress markers, reduced the activity of the innate immune system, suppressed specific immunity to a lesser degree and yielded less discomfort and cold sensation. We found a negative correlation between body mass index and Δ metabolic heat production before and after CA.