Heart Rate Variability as a Marker of Training Load, Recovery and Overtraining in Athletes – A Systematic Review

Abstract

Heart rate variability (HRV) is an indicator of autonomic nervous system activity and a useful tool for monitoring training load, recovery, and adaptation in athletes. It reflects the balance between sympathetic and parasympathetic activity. Decreases in HRV are generally associated with fatigue and increased training load, whereas stable or elevated values may indicate recovery and positive adaptation. However, the relationship is complex and non-linear. This review aims to summarize knowledge about the utility of Heart Rate Variability (HRV) as a parameter for monitoring training load, recovery, and overall athlete readiness. The literature included in this review focused on the use of heart rate variability (HRV) as a tool for athlete monitoring. Particular attention was given to studies examining the relationship between HRV and training load, recovery processes, overtraining, factors affecting HRV measurements, and the implementation of HRV-guided training approaches. Priority was assigned to original research papers, systematic reviews, meta-analyses, and narrative reviews published within the past decade. Earlier publications were also considered when they constituted foundational research or provided essential context for understanding the topic. Taken together, these findings suggest that HRV is a useful marker of autonomic nervous system activity with considerable relevance in sports science. Its practical value, depends on proper interpretation, an individualized perspective, and its combination with other monitoring methods. Instead of serving as an independent diagnostic measure, HRV should be considered part of a broader framework for assessing training load, recovery, and overall athlete readiness.