Effects of Elevated Body Temperature on Selected Physiological Indices and Thermal Stress in Athletes and Non-Athletes

Wanda Pilch; Małgorzata Żychowska; Anna Piotrowska; Olga Czerwińska-Ledwig; Wioletta Mikuľáková; Ewa Sadowska-Krępa

doi:10.2478/hukin-2021-0131

Effects of Elevated Body Temperature on Selected Physiological Indices and Thermal Stress in Athletes and Non-Athletes

J Hum Kinet. 2022 Nov 8:84:112-123. doi: 10.2478/hukin-2021-0131. eCollection 2022 Oct.

Authors

Wanda Pilch¹, Małgorzata Żychowska², Anna Piotrowska¹, Olga Czerwińska-Ledwig¹, Wioletta Mikuľáková³, Ewa Sadowska-Krępa⁴

Affiliations

¹ Institute for Basics Sciences, Faculty of Physiotherapy, University of Physical Education in Krakow, Krakow, Poland.
² Department of Sport, Faculty of Physical Education, Kazimierz Wielki University in Bydgoszcz, Bydgoszcz, Poland.
³ Department of Physiotherapy, Faculty of Health Care, University of Prešov, Prešov, Slovakia.
⁴ Institute of Sport Sciences, Academy of Physical Education in Katowice, Katowice, Poland.

Abstract

The purpose of this study was to determine the effects of active and passive overheating. A group of athletes (A) and non-athletic men (N) underwent an exercise stress test at elevated ambient temperature and sauna bathing until an increase in rectal temperature of 1.2°C was observed. It was shown that group A performed physical exercise for a longer period of time, which elicited significantly higher amounts of work performed in the stress test. Both forms of overheating caused a significant decrease in BM and a significant change in plasma volume, while greater dehydration was observed after active overheating. Changes observed in group A were higher than in group N. MCV levels were initially higher in group A. The levels in both groups decreased after sauna bathing, although in non-athletes the decrease was greater. Both forms of overheating increased Hb, HCT, and SBP, while only the non-athletic group showed a decrease in DBP after the exercise stress test. However, a decrease in DBP was observed in both groups after sauna bathing. The PSI increased after both tests, yet to a higher extent after the stress test than after sauna bathing. The PSI was negatively correlated with VO_2max in both groups. The increase in cortisol concentration was higher after sauna bathing. There was a correlation between cortisol levels and the work performed during the stress test in group A. Endurance training resulted in more efficient thermoregulatory mechanisms in athletes.

Keywords: Physiological Stress Index; active overheating; passive overheating; thermoregulation.