Test-Retest Reliability of Heart Rate and Parasympathetic Modulation Indices Across Exercise and Recovery Phases in...

Area of Science:

• Sports Science and Exercise Physiology
• Cardiovascular Physiology
• Biomedical Engineering

Background:

• Understanding the reliability of physiological measures is crucial for monitoring athlete training loads and recovery.
• Heart rate (HR) and parasympathetic modulation (RMSSD) are key indicators of physiological stress and recovery.
• Previous research has not consistently evaluated the within-session reliability of these markers across different exercise and recovery phases in elite athletes.

Purpose of the Study:

• To examine the same-day test-retest reliability of heart rate (HR) and root mean square of successive differences (RMSSD).
• To assess reliability across resting, pre-exercise, and multiple post-exercise recovery time points (~10-20 min, 1 h, 3 h).
• To determine the impact of measurement timing on the reliability of these physiological markers in trained soccer players.

Main Methods:

• Twenty-seven trained male soccer players participated in the study.
• Standardized soccer training session followed by ECG-based chest-strap monitoring of HR and RMSSD.
• Two consecutive 5-minute seated recordings at rest, pre-exercise, and ~10-20 min, 1 h, 3 h post-exercise.

Main Results:

• Heart rate (HR) demonstrated excellent within-session reliability across all measurement points (ICC = 0.980-0.994).
• RMSSD showed excellent reliability at rest and pre-exercise (ICC > 0.918) but moderate reliability in early recovery (~10-20 min; ICC = 0.551).
• RMSSD reliability improved to good levels at 1 h (ICC = 0.826) and 3 h (ICC = 0.873) post-exercise, with no significant systematic differences between tests.

Conclusions:

• Within-session reliability of heart rate (HR) is consistently high for trained soccer players during exercise and recovery.
• The reliability of parasympathetic modulation (RMSSD) is dependent on the timing of measurement, being less reliable during immediate post-exercise recovery.
• These findings highlight the importance of considering measurement timing when using RMSSD for monitoring athlete recovery status.