Wikipedia
Heart-related component of physical fitness
Summary
Cardiovascular fitness is a component of physical fitness, which refers to a person’s ability to deliver oxygen to the working muscles, including the heart. Cardiovascular fitness is improved by sustained physical activity (see also endurance training) and is affected by many physiological parameters, including cardiac output (determined by heart rate multiplied by stroke volume), vascular patency, and maximal oxygen consumption (i.e. VO2 max).