Finaly NPY, the sympathetic co-transmitter which
causes vasoconstriction, decreases coronary blood
flow and decreases cardiac output (Hauser et al.
1996) was seen to diminish significantly with the two
levels of exercise, hence, denoting positive circulatory
adaptations with exercise. The fact that the chronic
circulating levels of the immunoreactive NPY
decreased to a similar extent with both exercise
intensities reinforces the effectiveness of lower exercise
intensity in the older age group.