Document Type : Research Paper
Authors
1
MSc., Department of Exercise Physiology, University of Guilan, Rasht, Guilan, Iran
2
Department of Exercise physiology, University of Guilan, Rasht, Iran
3
Department of Physical Education and Sports Science Faculty, University of ImamJavad, yazd, Iran
10.22080/jaep.2025.30168.2232
Abstract
Objectives: Ambient temperature modulates autonomic nervous system activity, thereby affecting heart rate and blood acidosis. This study examined how a single bout of anaerobic exercise performed under different environmental temperatures influences heart rate variability (HRV) and blood acidosis in trained individuals.
Methods: This semi‑experimental applied study used a crossover, counterbalanced design with 12 trained athletes (24.41 ± 4.01 years; 171.2 ± 7.16 cm; 70.65 ± 11.16 kg). Each participant completed three Wingate anaerobic tests under different temperature conditions: high (40°C), normal (20°C), and low (8–15°C), with one‑week intervals between sessions. Heart rate was recorded during exercise to assess HRV indices (HF, LF, LF/HF, RMSSD) using Kubios software. Blood samples were taken before and immediately after activity to measure lactate and bicarbonate levels. Research variables were analyzed using one‑way ANOVA at a significance level of p < 0.05
Results: The ANOVA test results indicated a significant difference between different temperatures in RMSSD (p = 0.001), LF (p = 0.036), HF (p = 0.001), and LF/HF ratio (p = 0.001). Additionally, a significant difference in lactate levels was observed among the three temperature conditions (p = 0.017). However, there was no significant difference in pH levels and bicarbonate ion concentration.
Conclusion: The findings suggest that performing anaerobic activity in different thermal environments affects heart rate variability and tissue acidosis, potentially influencing athletic performance. Moreover, the results of this study can be useful for assessing disturbances in acid-base balance and providing clinical guidelines to maintain athletes' physiological function.
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