Brachial arterial dynamics during staged lower extremity exercise: utility and comparison in physically active versus sedentary subjects.

Constriction and relaxation of peripheral conduit arteries in response to exercise and recovery are amenable to noninvasive imaging. Diameter changes in the brachial artery during stationary bicycle pedaling are paradoxical to those in the lower extremities. When exercise is confined to the legs, arteries in the upper extremities constrict while leg arteries dilate. The magnitude of vasoconstriction in the upper extremities reflects the integrity of exercise mediated vascular responses. In the current study, young and old men with various levels of physical activity and cardiovascular histories exercised on a stationary bicycle while brachial artery diameter and flow velocity were continuously obtained. Results suggest that normal aging blunts arterial reactivity in seniors even if they exercise regularly. However, arterial dysfunction is greater when associated with sedentary lifestyle. This methodology of imaging brachial artery diameter changes during bicycle pedaling appears to be an effective tool for assessing the physiologic integrity of the vascular bed.