HRV-Guided Training: The Challenge Is Not the Data, but the Decision

• This article evaluates the use of heart rate variability (HRV) to guide endurance training and adjust training load according to an individual’s recovery status. The authors show that HRV-guided training can improve the consistency of training adaptations and may be especially useful for submaximal and autonomic outcomes, although it does not consistently produce greater improvements in VO₂max or endurance performance than predefined training programs.

• A major limitation is that HRV is influenced by many factors beyond training, such as sleep, illness, stress, hydration, and environmental conditions, so it should not be used as a single indicator of readiness.

• The paper also highlights the lack of standardized and transparent decision-making frameworks, particularly in commercial wearable systems that often use proprietary readiness or recovery scores.

• Overall, the main message is that the key challenge is no longer collecting HRV data, but interpreting it correctly and integrating it with other physiological, perceptual, and contextual information in transparent, individualized, and evidence-based training decisions. (Schaffarczyk, M., & Sperlich, B. (2026). Heart rate variability–guided endurance training: evaluating strengths, weaknesses, opportunities, and threats for load prescription and adjustment. Frontiers in Sports and Active Living, 8, 1858271.)