Aging, cardiorespiratory fitness and sympathetic transduction

increases cardiovascular disease risk (e.g., hypertension). Engagement in sufficient moderate-tovigorous physical activity to maintain a high cardiorespiratory fitness (CRF) attenuates the negative cardiovascular impact of aging. The vasoconstrictor arm of the sympathetic nervous system is critical for effective short-term arterial blood pressure regulation. Sympathetic neural activity directed towards skeletal muscle resistance vessels (muscle sympathetic nerve activity; MSNA) causes peripheral vasoconstriction, which is exaggerated in older adults [1]. Signal averaging techniques have been developed [2], and refined [3], to quantify the communication between MSNA and the corresponding pressor or local vascular responses (i.e., sympathetic transduction). The assessment of sympathetic transduction may help uncover the divergent cardiovascular implications of inactive (lower CRF) versus active (higher CRF) aging.