Cardiac Autonomic Function Following Bilateral and Unilateral Upper Body Acute Resistance Exercise

Area of Science:

• Exercise Physiology
• Autonomic Nervous System Function
• Cardiovascular Regulation

Background:

• Acute resistance exercise (ARE) impacts autonomic nervous system (ANS) control of the heart.
• Understanding the differential effects of exercise laterality on cardiac autonomic responses is crucial for exercise prescription.

Purpose of the Study:

• To compare cardiac autonomic responses after bilateral versus unilateral upper-body (UB) ARE.
• To investigate the time course of recovery for heart rate variability (HRV) and baroreflex sensitivity (BRS) following UB ARE.

Main Methods:

• 14 participants underwent assessment of HRV and baroreflex sensitivity (BRS) at rest and 10, 30 minutes post-bilateral and unilateral UB ARE.
• HRV metrics (ln TP, ln HF power, ln LF power, ln LF:HF, ln RMSSD) and BRS were analyzed using two-way repeated measures ANOVAs.

Main Results:

• No significant interactions between exercise type (bilateral vs. unilateral) and time were observed.
• Significant main effects of time indicated decreases in ln TP, ln HF power, ln RMSSD, and BRS at 10 and 30 minutes compared to rest for both conditions.
• These autonomic markers did not fully recover within 30 minutes post-exercise.

Conclusions:

• Both bilateral and unilateral UB ARE similarly reduce vagal modulation of cardiac autonomic function.
• Reductions in HRV and BRS persist for at least 30 minutes following UB ARE, regardless of laterality.
• These findings suggest comparable autonomic stress from bilateral and unilateral UB resistance exercise.