Comparison of sympathetic nerve activity during handgrip exercise performed with the dominant and non-dominant arm.

To investigate whether handedness influences sympathetic nerve responses during exercise, muscle sympathetic nerve activity (MSNA), heart rate, and blood pressure during maximal voluntary handgrip exercise under ischemic conditions (MVHG) and during post-exercise ischemia (PEI) were compared between the dominant (DA) and non-dominant arm (NDA) in eight left-handed subjects. MSNA expressed as burst frequency or total activity (TSNA) and blood pressure increased significantly during MVHG and PEI. Although the heart rate rose during MVHG, it returned to resting level during PEI. The increased MSNA was less in DA exercise than the NDA, while no significant differences in heart rate and blood pressure response were observed. The results suggest that handedness seems to influence reflex sympathetic activation during muscular contraction, but has no significant effect on heart rate or blood pressure.