Neurovascular control following small muscle mass exercise in humans (1170.10)

Sympathetic vascular transduction is blunted and the arterial baroreflex curve is reset to a lower operating pressure after dynamic large muscle mass exercise in humans. It is unknown whether these neural adaptations contribute to sustained post‐exercise vasodilation in small muscle mass exercise. The purpose of this study was to determine if cardiovagal, vascular, and integrated baroreflex sensitivity as well as sympathetic neurovascular transduction were altered following dynamic knee extension (DKE) exercise. It was hypothesized that sympathetic vascular transduction would be reduced after DKE, the arterial baroreflex would be reset to a lower operating point, and baroreflex sensitivity would be enhanced. Eleven healthy, college‐aged subjects completed one‐leg DKE exercise for one hour at 60% of peak power. Neurovascular transduction was estimated by measuring the percent change in femoral vascular conductance due to external neck pressure. There was no effect of exercise on transduction (P = 0.46) and no difference in integrated baroreflex sensitivity across time (P = 0.77). Cardiovagal baroreflex sensitivity increased 25% relative to baseline and had not recovered at 60 minutes post‐exercise (P = 0.02). Vascular baroreflex sensitivity was reduced in both the exercised (P = 0.05) and rested leg (P = 0.09). There is likely no effect of small muscle mass exercise on postexercise sympathetic transduction, the carotid baroreflex, or integrated baroreflex sensitivity. Cardiovagal baroreflex sensitivity was augmented and vascular baroreflex sensitivity was reduced after exercise and this has not been previously shown after small muscle mass exercise. Grant Funding Source : NIH R01 HL115027