Heart rate variability mediates motivation and fatigue throughout a high-intensity exercise program.

Area of Science:

• Exercise Physiology
• Autonomic Nervous System Function
• Behavioral Science

Background:

• High-intensity exercise is promoted for public health but faces adherence challenges due to fatigue.
• Heart rate variability (HRV) reflects autonomic nervous system balance and may influence exercise behavior.
• Understanding HRV's role is crucial for optimizing exercise adherence.

Purpose of the Study:

• To investigate if heart rate variability (HRV) mediates exercise adherence by influencing motivation and fatigue.
• To explore the relationship between HRV, exercise-induced fatigue, and motivation during a high-intensity program.
• To identify potential strategies for enhancing long-term adherence to high-intensity exercise.

Main Methods:

• Fifty-five healthy adults (19-35 years) participated in a 6-week high-intensity exercise intervention.
• Daily HRV was monitored using a smartphone application.
• Participants self-reported exercise motivation and physical fatigue before each session.

Main Results:

• Increased parasympathetic reactivation (indicated by HRV) correlated with higher fatigue and lower motivation.
• Conversely, parasympathetic withdrawal was associated with reduced fatigue and increased motivation.
• Modulating exercise volume in response to HRV shifts reversed negative effects on fatigue and motivation.

Conclusions:

• HRV significantly mediates exercise adherence by influencing daily fatigue and motivation levels.
• Appropriate exercise volume adjustments, guided by HRV, can enhance adherence to high-intensity programs.
• This study provides novel insights into leveraging HRV for sustained exercise participation.