Abstract
Heat acclimation (HA) protocols have been under constant development since the 20th century, with the optimal HA approach yet to be determined. Adaptations from traditional approaches likely favor aerobic performance due to the nature of low- to moderate-intensity, endurance-based exercise in the heat. However, individuals involved in team sports, military personnel, and occupational workers may benefit from adaptations induced by a HA protocol that is more sport-/activity-specific. PURPOSE: To investigate differences in environmental symptomatology during a circuit training session in the heat (35°C; 40% relative humidity [RH]) following short-term (5 day) circuit training in hot and thermoneutral environmental conditions. METHODS: Sixteen physically active males participated in this between-subjects experimental design (age, 24 ± 4 years; height, 177 ± 8 cm; weight, 82.3 ± 12.7 kg). Subjects were randomly stratified into two groups: a) circuit training in the heat (35°C; 40% RH [n = 8]), or b) circuit training in thermoneutral conditions (20°C; 40% RH [n = 8]). Each condition consisted of 5 total circuit training sessions conducted over 8 days. Stratification revealed no significant differences in age (p = 0.537), height (p = 0.889), weight (p = 0.634), aerobic capacity (p = 0.128), body fat percentage (p = 0.756), and upper body muscular endurance (p = 0.262). Pre- and post-testing consisted of all subjects performing a standardized circuit training protocol in the heat (35°C; 40% RH), with an environmental symptoms questions (ESQ) administered prior to and immediately following exercise. A linear mixed-effects model with Tukey post-hoc tests were used to assess significant changes in ESQ categories from pre- to post-testing between conditions. Statistical significance was accepted at p < 0.05. RESULTS: Linear mixed-effects models revealed significantly lower symptomology from pre- to post-testing for trouble concentrating (p = 0.026), feeling hot (p = 0.013), feeling nauseous (p = 0.012), feeling thirsty (p = 0.003), and feeling weak (p = 0.007) in the heat condition, whereas no significant changes were observed under thermoneutral conditions (all p > 0.17). CONCLUSION: A short-term circuit training conducted in the heat was effective in reducing environmental symptoms during whole-body exercise in the heat, whereas conducting circuit training in a thermoneutral condition provided no benefit in terms of reducing symptomology.
Recommended Citation
King, Jenna; Dunn, Ryan; Brojanac, Alexandra; Hernandez, Mario; and Sekiguchi, Yasuki
(2026)
"The Effects of Multiple Circuit Training Sessions in Hot Compared to Thermoneutral Environmental Conditions on Environmental Symptomology,"
International Journal of Exercise Science: Conference Proceedings: Vol. 2:
Iss.
18, Article 21.
Available at:
https://digitalcommons.wku.edu/ijesab/vol2/iss18/21
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