title: Effects of cold environment exposure and cold acclimatization on exercise-induced salivary cortisol response.
abstract: OBJECTIVE
  Considering the adverse effects of exercise-induced cortisol secretion on health in athletes, it is important to determine the environmental and individual factors that contribute to the variations in exercise-induced cortisol secretion. In this study, the effects of cold environment exposure and cold acclimatization on exercise-induced salivary cortisol responses were investigated.
  
  
  METHODS
  Short track skaters (n = 11), who usually practice under cold conditions, and inline skaters (n = 11), who usually practice under room temperature conditions, participated in a randomized crossover study. All participants cycled for 60 minutes at 65% Vo2 max under cold (ambient temperature: 5 +/- 1 degrees C, relative humidity 41% +/- 9%) and room temperature (ambient temperature: 21 +/- 1 degrees C, relative humidity 35% +/- 5%) conditions. The participants had a 120-minute bed rest recovery phase at room temperature after both exercise bouts. Cortisol levels were measured in saliva samples collected pre-exercise and postexercise at 1 minute, 30 minutes, 60 minutes, and 120 minutes.
  
  
  RESULTS
  Both short track and inline skaters exhibited clear cortisol responses to exercise under cold and room temperature conditions. The magnitude of the cortisol response, however, was different between skaters and conditions. The inline skaters exhibited significantly higher cortisol values under cold conditions than under room temperature conditions (7.6 nmol/L and 4.2 nmol/L, respectively). However, the short track skaters exhibited significantly higher cortisol values under cold conditions compared to room temperature conditions (8.7 nmol/L and 5.4 nmol/L, respectively).
  
  
  CONCLUSIONS
  The effects of cold environment exposure on exercise-induced cortisol response were different between skaters who usually practice under cold or room temperature conditions. These results can be interpreted as acclimatization to either cold or room temperature conditions attenuating the cortisol response, suggesting that acclimatization may be beneficial in reducing the exercise-induced cortisol response.
authors.affiliation: Institute for Biomedical Engineering, Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, Tokyo, Japan. izawa@aoni.waseda.jp
authors.forename: Shuhei
authors.initials: S
authors.lastname: Izawa
authors.forename: Kijin
authors.initials: K
authors.lastname: Kim
authors.forename: Takayuki
authors.initials: T
authors.lastname: Akimoto
authors.forename: Nayoung
authors.initials: N
authors.lastname: Ahn
authors.forename: Hoseong
authors.initials: H
authors.lastname: Lee
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000328:Adult; D003080:Cold Temperature; D018592:Cross-Over Studies; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis / Q000378:metabolism*; D008297:Male; D010101:Oxygen Consumption; D012463:Saliva / Q000378:metabolism*; D012861:Skating / Q000502:physiology*; D013696:Temperature
chemical_list: D006854:Hydrocortisone