Reliability of the Heart Rate Variability Threshold using Visual Inspection and Dmax Methods

Area of Science:

• Exercise Physiology
• Cardiovascular Physiology
• Sports Science

Background:

• Heart Rate Variability Threshold (HRVT) is a key indicator of exercise intensity.
• Accurate determination of HRVT is crucial for training prescription and performance analysis.
• Existing methods for HRVT assessment vary in reproducibility.

Purpose of the Study:

• To compare the reproducibility of HRVT across six incremental tests.
• To evaluate visual inspection and Dmax methods for determining HRVT.
• To assess the reliability of RMSSD, SDNN, and SD1 indices for HRVT analysis.

Main Methods:

• 12 adult males completed incremental cycle tests to volitional fatigue.
• Heart Rate Variability (HRV) was analyzed using RMSSD, SDNN, and SD1 indices.
• HRVT was determined via visual inspection and Dmax methods.

Main Results:

• The visual inspection method using SD1 and RMSSD indices showed the highest HRVT reproducibility.
• This method demonstrated a lower coefficient of variation and smaller increment size.
• Other indices and the Dmax method yielded less reproducible HRVT values.

Conclusions:

• Visual inspection of SD1 and RMSSD indices is the optimal method for determining HRVT.
• This technique offers superior reproducibility, crucial for reliable physiological assessments.
• The findings support the use of this method in incremental exercise testing protocols.