Static handgrip exercise modifies arterial baroreflex control of vascular sympathetic outflow in humans

To examine effects of static exercise on the arterial baroreflex control of vascular sympathetic nerve activity, 22 healthy male volunteers performed 2 min of static handgrip exercise at 30% of maximal voluntary force, follow ed by postexercise circulatory arrest (PE-CA). Microneurographic recording of muscle sympathetic nerve activity (MSNA) was made with simultaneous reco rding of arterial pressure (Portapres). The relationship between MSNA and d iastolic arterial pressure was calculated for each condition and was define d as the arterial baroreflex function. There was a close relationship betwe en MSNA and diastolic arterial pressure in each subject at rest and during static exercise and PE-CA. The slope of the relationship significantly incr eased by >300% during static exercise (P< 0.001), and the x-axis intercept (diastolic arterial pressure level) increased by 13 mmHg during exercise (P < 0.001). These alterations in the baroreflex relationship were completely maintained during PE-CA. It is concluded that static handgrip exercise is a ssociated with a resetting of the operating range and an increase in the re flex gain of the arterial barorelex control of MSNA.