Stroke volume (SV) changes during graded exercise were studied in a) elite male distance runners (N = 5), b) male
university
distance runners (N = 10), and c) male untrained
university students (N = 10). All groups responded with a similar SV increase in the transition from rest to light exercise. During the transition from light to maximal exercise, the groups responded differently. The untrained group exhibited a reduction in SV, the university runners
increased slightly, and the elite runners increased significantly and dramatically. Elite runners also increased SV when heart rate exceeded 160 bpm.The university and untrained groups exhibited the classic phenomenon of the SV plateauing at about 40% maximum oxygen consumption despite increasing exercise intensity. Elite runners did not fit that description.
Implication. Elite runners respond to intense exercise with different stroke volume dynamics than those generally considered normal responses for trained individuals.