ABSTRACT
Endurance training, whether continuous or intermittent in nature, will increase how much blood the heart pumps per minute: Cardiac Output, mainly, by increasing maximal stroke volume (blood pumped per beat) with no change in Heart Rate (beats per minute). The size of the left ventricle of the heart is enlarged with endurance training. Blood volume or specifically plasma volume is a determinant of stroke volume as the greater the plasma volume the greater the venous return and the more blood the heart will pump. Blood volume increases with training. Cardiac output is one of the major determinants of VO2max/peak which is also dictated by the Arteriovenous Oxygen Difference (A-VO2diff) which means extraction of oxygen at the tissue level: VO2max/peak = CO × A-VO2diff. A-VO2diff is improved by an increase in capillarity in muscle beds and mitochondrial number and function and an increase in mitochondrial enzymes.
