Stroke volume

Stroke volume is the amount of blood your left ventricle pumps out per heartbeat. At rest in healthy adults, that is about 60 to 100 ml. In elite endurance athletes at peak effort, it can reach 150 to 200 ml or more. Together with heart rate, it sets your cardiac output (cardiac output = stroke volume × heart rate). That, in turn, caps your VO2max. The main way it ramps up is the Frank-Starling response. More blood returning to the heart stretches the ventricle wall during filling (diastole), raises the end-diastolic volume, and boosts the force of contraction. Endurance training improves this further. It does so through a larger ventricle (eccentric hypertrophy), more blood volume, faster filling, and lower resistance for the heart to pump against. Gledhill et al. (1994) showed that competitive cyclists keep raising stroke volume all the way to VO2max, while sedentary people plateau early. Vella and Robergs (2005) gathered four response patterns: plateau, plateau-with-drop, plateau-with-secondary-rise, and progressive increase. Which one you get depends on training, blood volume, age, and sex. Aging lowers stroke volume, through a stiffer ventricle and slower early filling. That feeds the roughly 10%-per-decade VO2max decline after about age 25 in sedentary people. A higher stroke volume at a given heart rate means a more efficient pump. And it directly supports aerobic capacity, one of the strongest independent predictors of all-cause death. So aerobic training and good hydration are central to your cardiovascular healthspan.

Last reviewed: June 22, 2026

This definition is educational and is not medical advice, a diagnosis, or treatment. Talk to a doctor about any health decisions. Read our full medical disclaimer