A simple approach to assess VT during a field walk test

Area of Science:

• Exercise Physiology
• Cardiorespiratory Fitness Assessment
• Non-invasive Physiological Monitoring

Background:

• The ventilatory threshold (VT) is a key indicator of exercise intensity and aerobic capacity.
• Assessing VT typically requires gas exchange measurements, limiting its practical application.
• Heart rate variability (HRV) offers a potential non-invasive method for monitoring autonomic responses during exercise.

Purpose of the Study:

• To investigate if heart rate variability (HRV) analysis can determine the ventilatory threshold (VT) during an incremental shuttle walk test (ISWT).
• To identify predictors of performance and exercise intensity during the ISWT.
• To validate HRV-derived VT measurements against traditional methods.

Main Methods:

• 10 healthy participants underwent an incremental shuttle walk test (ISWT) with simultaneous collection of beat-to-beat RR intervals and gas exchange data.
• Ventilatory threshold (VT) was determined using the ventilatory equivalent method.
• A heart rate variability threshold (HRVT) was identified by plotting beat-to-beat variability against walking speed.

Main Results:

• No significant difference was found between walking speed at VT and HRVT (5.04±1.00 vs. 5.10±1.04 km/h; p=0.89).
• A strong linear correlation (r²=0.896) and good agreement were observed between VO2VT and VO2HRVT.
• HRV analysis provides a reliable, non-invasive method for VT assessment during ISWT.

Conclusions:

• The ventilatory threshold (VT) can be accurately assessed during the incremental shuttle walk test (ISWT) using simple heart rate variability (HRV) analysis.
• This non-invasive approach simplifies exercise capacity assessment and aids in personalized walking program prescription.
• ISWT combined with HRV offers a practical tool for evaluating fitness and guiding exercise interventions.