Document Type : Research Paper
Authors
1
Department of Exercise Physiology, Faculty of Sport Sciences, University of Guilan, Rasht, Iran.
2
Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, University of Guilan, Rasht, Iran.
3
Department of Physical Education and Sports Science, Faculty of Basic Sciences, University of Imam Javad, Yazd, Iran
10.22080/jaep.2025.30168.2232
Abstract
Objectives: Ambient temperature can alter the activity of the autonomic nervous system, leading to changes in heart rate and influencing tissue acidosis in the blood, which affects athletic performance. Therefore, the present study aimed to investigate the effect of a single session of anaerobic exercise at different environmental temperatures on heart rate variability (HRV) and blood acidosis in trained individuals.
Methods: This study was a semi-experimental and applied research conducted in a crossover and counterbalanced design. A total of 12 athletes voluntarily participated in the study, with a mean age of (24.41 ± 4.01 years), height of (171.2 ± 7.16 cm), and weight of (70.65 ± 11.16 kg). The participants underwent three trials in different temperature conditions: high (40°C), normal (20°C), and low (8–15°C). Each trial was separated by a one-week rest period. During each session, they performed the Wingate anaerobic test. Heart rate data were recorded using a heart rate monitor to assess heart rate variability (HRV) during activity. The recorded data were analyzed using Kubios software to calculate HRV parameters, including high-frequency (HF) and low-frequency (LF) waves, the LF/HF ratio, and RMSSD. Blood samples (5 cc) were collected from the brachial vein before and immediately after exercise and were subsequently transferred to a laboratory for lactate and bicarbonate ion analysis. Additionally, a one-way ANOVA test was used to analyze the research variables at a significance level of p ≤ 0.05.
Results: 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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