EFFECTS OF GENDER ON SYMPATHETIC NEURAL OUTFLOW DURING EXERCISE

During exercise stimulation of muscle "metaboreceptors" (afferent nerve fibers) contribute to the observed "exercise pressor reflex" and an increase in muscle sympathetic nerve activity(MSNA). We previously reported that MSNA (peroneal nerve, microneurography) was attenuated in women as compared to men during a static handgrip exercise paradigm. However, differences in MVC, muscle mass and physical training status could have contributed to this gender related effect. This study performs an "isolated muscle exercise" using the adductor pollicus. With this muscle, cross sectional area is linked to MVC, and differences in MVC in men and women are small. MSNA responses during static thumb exercise to fatigue at 60% MVC followed by post-exercise circulatory arrest are studied.