HEART RATE VARIABILITY IN ATHLETES: INDICATOR OF TRAINING LOAD, RECOVERY AND CARDIOVASCULAR HEALTH

Abstract

Introduction: Heart rate variability (HRV) is a non-invasive biomarker reflecting autonomic nervous system activity. In recent years, its use in sports medicine has increased significantly due to its usefulness in monitoring training load, recovery, and cardiovascular health in athletes. Material and methods: This review summarizes the current state of knowledge on the physiological basis of HRV, measurement methods, and practical applications in athlete populations. This study is a literature review based on data from PubMed and Google Scholar. Results: HRV parameters, particularly RMSSD (the square root of the mean of the squares of differences between successive RR intervals) and SDNN (the standard deviation of NN intervals), show a clear sensitivity to training intensity and recovery status. Studies show that HRV-guided training can improve performance measures such as VO₂max (maximal oxygen consumption) and reduce the risk of overtraining. HRV also responds to changes related to sleep quality, supplementation, and biofeedback interventions. Despite technological advances, there are still challenges related to standardizing measurement protocols and accuracy across devices. Low HRV is also associated with increased cardiovascular risk, which additionally creates a potential role in early detection of arrhythmia or autonomic imbalance in athletes. Conclusions: HRV is a valuable tool in personalized training management and monitoring cardiovascular health. The use of similar measurement protocols and interpretation of trends rather than single values increases its utility in both competitive and recreational sports. Future research should seek to integrate HRV with other physiological measures and validate wearable technologies in diverse athlete populations.