Cardiac output is the amount of blood pumped out of the heart per minute and therefore will vary depending on the intensity of the exercise. It is calculated as the stroke volume multiplied by the number of heartbeats per minute.
I have seen a blog here saying the elite athlete’s CO goes down at rest, but there is no reference to any form of research on that page. Physiologically there are some aspects that make it so that an elite athlete’s heart may have a similar or lower CO such as their decreased resting heart rate, and increased haemoglobin. However, even at rest elite athletes burn more energy than a non-trained person and so require more oxygen to maintain their increased resting metabolic rate
At rest, research has shown an increase from 5-7L/min in endurance trained athletes and this change can become up to 40L/min at maximal intensity. There is an article here, as well as here and here. If you’re worried get them to teach that at any given heart rate the trained athlete has a higher CO.
