Modification of heart rate and the regulation of the redistribution of blood by nervous stimulation. The lowering of heart rate associated with endurance training, for example, is thought to be due mainly to an increase in stimulation from the vagus nerve (an inhibitory nerve). Most blood vessels are supplied with nerves from the sympathetic nervous system. During exercise, sympathetic stimulation increases. This causes blood vessels in the gut to constrict and those in the heart and skeletal muscle to dilate, enabling blood to be shunted from the gut to the heart and skeletal muscles (see shunting).
Subjects: Sports and Exercise Medicine.