title: Effects of long-term whole-body cold exposures on plasma concentrations of ACTH, beta-endorphin, cortisol, catecholamines and cytokines in healthy females.
abstract: 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.
authors.affiliation: Department of Physiology, University of Oulu, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Leppäluoto
authors.forename: T
authors.initials: T
authors.lastname: Westerlund
authors.forename: P
authors.initials: P
authors.lastname: Huttunen
authors.forename: J
authors.initials: J
authors.lastname: Oksa
authors.forename: J
authors.initials: J
authors.lastname: Smolander
authors.forename: B
authors.initials: B
authors.lastname: Dugué
authors.forename: M
authors.initials: M
authors.lastname: Mikkelsson
mesh_terms: 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*
chemical_list: D002395:Catecholamines; D016207:Cytokines; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone