Effects of cold environment exposure and cold acclimatization on exercise-induced salivary cortisol response.
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.
Izawa
Shuhei
S
Institute for Biomedical Engineering, Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, Tokyo, Japan. izawa@aoni.waseda.jp
Kim
Kijin
K
Akimoto
Takayuki
T
Ahn
Nayoung
N
Lee
Hoseong
H
Suzuki
Katsuhiko
K
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
D006854:Hydrocortisone