Effects of long-term whole-body cold exposures on plasma concentrations of ACTH, beta-endorphin, cortisol, catecholamines and cytokines in healthy females.
OBJECTIVE
Cold therapy is used to relieve pain and inflammatory symptoms. The present study was designed to determine the influence of long-term regular exposure to acute cold temperature. Two types of exposure were studied: winter swimming in ice-cold water and whole-body cryotherapy. The outcome was investigated on humoral factors that may account for pain alleviation related to the exposures.


METHODS
During the course of 12 weeks, 3 times a week, a group of healthy females (n = 10) was exposed to winter swimming (water 0-2 degrees C) for 20 s and another group (n = 10) to whole-body cryotherapy (air -110 degrees C) for 2 min in a special chamber. Blood specimens were drawn in weeks 1, 2, 4, 8 and 12, on a day when no cold exposure occurred (control specimens) and on a day of cold exposures (cold specimens) before the exposures (0 min), and thereafter at 5 and 35 min.


RESULTS
Plasma ACTH and cortisol in weeks 4-12 on time-points 35 min were significantly lower than in week 1, probably due to habituation, suggesting that neither winter swimming nor whole-body cryotherapy stimulated the pituitary-adrenal cortex axis. Plasma epinephrine was unchanged during both experiments, but norepinephrine showed significant 2-fold to 3-fold increases each time for 12 weeks after both cold exposures. Plasma IL-1-beta, IL-6 or TNF alpha did not show any changes after cold exposure.


CONCLUSIONS
The main finding was the sustained cold-induced stimulation of norepinephrine, which was remarkably similar between exposures. The frequent increase in norepinephrine might have a role in pain alleviation in whole-body cryotherapy and winter swimming.
Leppäluoto
J
J
Department of Physiology, University of Oulu, Finland.
Westerlund
T
T
Huttunen
P
P
Oksa
J
J
Smolander
J
J
Dugué
B
B
Mikkelsson
M
M
D000324:Adrenocorticotropic Hormone / Q000097:blood*; D002395:Catecholamines / Q000097:blood*; D003080:Cold Temperature; D016207:Cytokines / Q000097:blood*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D012016:Reference Values; D001615:beta-Endorphin / Q000097:blood*
D002395:Catecholamines; D016207:Cytokines; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone