A study of the effect of half-day climatotherapy on changes in salivary cortisol levels

Int J Biometeorol. 2024 May 15. doi: 10.1007/s00484-024-02698-2. Online ahead of print.

Abstract

In our previous study setting, climatotherapy programme consisted of six sessions - four in the mid-mountain area and two in a flat park. For all sessions, the subjects underwent climatotherapy in the morning under slightly cool conditions. During each session, the subjects' blood pressure, pulse rate, skin temperature, blood lactate, salivary cortisol and mood profile were recorded, and meteorological data were collected at the sites. We hypothesised that exercise habits, changes in mood profile and effective temperatures during the session, and physical exertion during the climatic terrain cure would affect salivary cortisol levels. Subjects were 30 (spring) and 29 (autumn). Multiple linear regression analyses were performed to examine the determinants of the change in salivary cortisol levels. In the mountain setting, salivary cortisol was elevated, even though the sessions took place in the descending phase of the circadian salivary cortisol variation; however, the post-session cortisol increase was not significant. Increased post-session salivary cortisol was significantly associated with female gender, older age, higher BMI, lower body fat, less daily physical activity, increased blood lactate, increased 'Tension-Anxiety' and 'Depression-Dejection' moods, and decreased 'Anger-Hostility' mood. The increase in cortisol may have been due to older age, a predominance of females, and the increased blood lactate due to the mountainous terrain. In the flat park, the significant decrease in postsession salivary cortisol was related to the descending circadian phase of circadian cortisol variation and the low physical demands of the sessions.

Keywords: Blood lactate; Circadian rhythm; Climatotherapy; Mood; Physical activity; Salivary cortisol.