Effect of exercise mode on heart rate variability during steady state exercise

Area of Science:

• Exercise Physiology
• Cardiovascular Physiology
• Autonomic Nervous System Function

Background:

• Heart rate variability (HRV) reflects autonomic nervous system balance.
• Different exercise modalities may elicit varied cardiovascular and autonomic responses.
• Understanding these differences is crucial for exercise prescription and interpretation of physiological markers.

Purpose of the Study:

• To investigate the impact of exercise mode (upper body, lower body, whole body) on heart rate variability (HRV) during moderate-intensity, steady-state exercise.
• To compare cardiorespiratory and perceptual responses across different exercise modes at matched heart rates.
• To determine if exercise modality influences specific time and frequency domain HRV measures.

Main Methods:

• Seventeen healthy males underwent VO2max testing.
• Participants completed 15-minute steady-state exercise bouts at 50% and 65% of maximal heart rate using arm ergometry, cycling, and treadmill.
• Heart rate variability, cardiorespiratory, and perceptual data were collected at rest and during exercise.
• Data were analyzed using two-way repeated measures ANOVA.

Main Results:

• Whole and lower body exercise yielded similar cardiorespiratory, perceptual, and HRV responses.
• Upper body exercise resulted in significantly greater HRV, particularly in very low and low-frequency bands (P < 0.05).
• Upper body exercise also showed greater rating of perceived exertion and lower oxygen consumption compared to other modes.

Conclusions:

• Moderate-intensity upper body exercise elicits higher heart rate variability than equivalent intensity lower or whole body exercise.
• The mechanisms driving this enhanced HRV during upper body exercise require further investigation.
• Clinical implications of increased HRV with upper body exercise warrant additional research.