Investigating the Acute Effect of Different Training Protocols on Heart Rate Variability

Area of Science:

• Sports Science
• Exercise Physiology
• Cardiovascular Research

Background:

• Heart rate variability (HRV) is a key indicator of autonomic nervous system function and recovery.
• Elite athletes utilize various training modalities, including high-intensity interval training (HIIT) and prolonged endurance training (ET).
• Understanding the acute effects of different training types on HRV is crucial for optimizing athlete recovery and performance monitoring.

Purpose of the Study:

• To examine the acute effects of HIIT versus ET on HRV in elite Greco-Roman wrestlers.
• To assess the utility of HRV for monitoring post-exercise recovery following these distinct training protocols.
• To compare the impact of two specific field-based conditioning sessions on physiological recovery markers.

Main Methods:

• A longitudinal, within-subject, repeated-measures design was employed with 13 elite male wrestlers.
• Participants completed two training protocols (ET and HIIT) in a fixed order, separated by a 15-day washout period.
• HRV was measured at baseline, pre-exercise, during exercise, and 24 hours post-exercise; data analyzed using linear mixed models and Bonferroni-corrected post hoc tests.

Main Results:

• Both HIIT and ET significantly reduced HRV parameters during exercise, with partial recovery observed at 24 hours.
• No significant differences in HRV parameters were found between the HIIT and ET protocols at any timepoint after Bonferroni correction.
• Despite a large effect size for the HRV Score during exercise, raw RMSSD showed a small, non-significant effect, indicating comparable recovery between protocols.

Conclusions:

• Both high-intensity interval training and prolonged endurance training elicit comparable acute effects on heart rate variability in elite wrestlers.
• HRV demonstrates similar recovery patterns 24 hours post-exercise for both training modalities in this population.
• The findings suggest that HRV may be a useful tool for monitoring recovery, but differences between these specific training protocols were not statistically significant in this study design.