The Fuzzy Kinetics Index: an indicator conflating cardiorespiratory kinetics during dynamic exercise

Area of Science:

• Exercise Physiology
• Cardiorespiratory Fitness
• Pulmonary Function

Background:

• Assessing exercise tolerance is crucial for understanding physiological limits.
• Current methods may not fully capture the complex interplay of cardiorespiratory and pulmonary systems during exercise.
• A novel approach is needed to integrate these kinetics for a comprehensive assessment.

Purpose of the Study:

• To develop a novel Fuzzy Kinetics Index (FKI) using fuzzy logic.
• To conflate cardiorespiratory and pulmonary kinetics during dynamic exercise.
• To establish FKI as a representative indicator for exercise tolerance.

Main Methods:

• Re-analyzed 69 datasets from dynamic exercise tests with pseudo-random binary sequence work rate changes.
• Measured heart rate, stroke volume, and pulmonary oxygen uptake (O2pulm) breath-by-breath.
• Applied fuzzy logic procedures using O2pulm and muscle oxygen uptake (O2musc) kinetics as input variables to calculate FKI.

Main Results:

• The Fuzzy Kinetics Index (FKI) showed significant correlations with both absolute and relative peak oxygen uptake (O2peak).
• Correlation was stronger for relative O2peak (r=0.430, p<0.001) compared to absolute O2peak (r=0.358, p<0.01).
• No significant correlations were found between FKI and age, height, or body mass.

Conclusions:

• Significant correlations between FKI and O2peak demonstrate a physiological link between regulatory and capacitive systems and exercise performance.
• FKI can serve as a valuable indicator for assessing exercise tolerance and sport performance in healthy individuals.
• This novel index offers a promising tool for non-invasive evaluation of physiological responses to exercise.