Time course of physiological and psychological responses in humans during a 20-day severe-cold-acclimation programme.
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.
Sports Science and Innovation Institute, Lithuanian Sports University, Kaunas, Lithuania.
Marius
M
Brazaitis
Sports Science and Innovation Institute, Lithuanian Sports University, Kaunas, Lithuania.
Nerijus
N
Eimantas
Department of Educational Studies, Kaunas University of Technology, Kaunas, Lithuania.
Laura
L
Daniuseviciute
Sports Science and Innovation Institute, Lithuanian Sports University, Kaunas, Lithuania.
Neringa
N
Baranauskiene
Department of Laboratory Medicines, Medical Academy, Lithuanian University of Health Science, Kaunas, Lithuania.
Erika
E
Skrodeniene
Sports Science and Innovation Institute, Lithuanian Sports University, Kaunas, Lithuania.
Albertas
A
Skurvydas
D000064:Acclimatization / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology*; D003080:Cold Temperature; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D013312:Stress, Physiological / Q000502:physiology*; D013315:Stress, Psychological / Q000503:physiopathology*; D013997:Time Factors; D055815:Young Adult