Cardiac output (CO) is the volume of blood ejected by the heart per minute. It is determined by multiplying heart rate and stroke volume. A large cardiac output is the major difference between untrained people and endurance
athletes. Untrained individuals may have a CO of 15 to 20 litres per minute. For trained athletes, CO is 20 to 25 litres per minute. In highly trained endurance athletes, CO may even rise as high as 40 litres per minute. What
is more exceptional is that the maximal heart rate of the trained athlete may be slightly lower than that of the
untrained person even when each person is working to their highest capacity. It follows that the trained athlete achieves a considerably higher CO not from heart rate, but as a direct result of a huge increase in stroke volume.
When a trained and untrained athlete are working at the same heart rate (beats per minute) the trained athlete will have a much higher cardiac output than an untrained one (can be over double for elite endurance athletes during maximal exercise). This is a direct result of a higher stroke volume in the trained athlete. However the trained person works more efficiently as the body adjusts the heart rate to meet the blood demands, so it is then seen that the cardiac output at rest and during sub-maximal exercise are often quite similar as the extra stroke volume is offset by the decrease in heart rate (this is why trained athletes have a lower exercise heart rate).
athletes. Untrained individuals may have a CO of 15 to 20 litres per minute. For trained athletes, CO is 20 to 25 litres per minute. In highly trained endurance athletes, CO may even rise as high as 40 litres per minute. What
is more exceptional is that the maximal heart rate of the trained athlete may be slightly lower than that of the
untrained person even when each person is working to their highest capacity. It follows that the trained athlete achieves a considerably higher CO not from heart rate, but as a direct result of a huge increase in stroke volume.
When a trained and untrained athlete are working at the same heart rate (beats per minute) the trained athlete will have a much higher cardiac output than an untrained one (can be over double for elite endurance athletes during maximal exercise). This is a direct result of a higher stroke volume in the trained athlete. However the trained person works more efficiently as the body adjusts the heart rate to meet the blood demands, so it is then seen that the cardiac output at rest and during sub-maximal exercise are often quite similar as the extra stroke volume is offset by the decrease in heart rate (this is why trained athletes have a lower exercise heart rate).