Mechanisms that underlie blood flow regulation at rest and during exercise.

The cardiovascular system must distribute oxygen and nutrients to the body while maintaining appropriate blood pressure. This is achieved through a combination of central and peripheral mechanisms that influence cardiac output and vasomotor tone throughout the vascular system. Furthermore, the capability to preferentially direct blood to tissues with increased metabolic demand (i.e., active hyperemia) is crucial to exercise tolerance. However, the interaction between these systems is difficult to understand without real-life examples. Fortunately, monitoring blood flow, blood pressure, and heart rate during a series of laboratory protocols will allow students to partition the contributions of these central and peripheral factors. The three protocols include ) reactive hyperemia in the forearm, ) small muscle mass handgrip exercise, and ) large muscle mass cycling exercise. In addition to providing a detailed description of the required equipment, specific protocols, and expected outcomes, this report also reviews some of the common student misconceptions that are associated with the observed physiological responses. Blood flow regulation during exercise is a complicated process that involves many overlapping mechanisms. This laboratory will help students better understand how the body regulates blood flow to the active muscles using three separate protocols: ) reactive hyperemia, ) small muscle mass exercise, and ) large muscle mass exercise.