Miguel Indurain

Fitness in terms of endurance activities like cycling is broadly determined by how much oxygen can be delivered to your working muscles.

This system starts with your lungs and heart and these work closely together in response to the levels of carbon dioxide (CO2) in your blood. As you begin to exercise, CO2 levels increase because CO2 is one of the waste products from burning fuel in your muscles.

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72 beats per min - the average adult resting heart rate4.8 litres - the average male adult lung capacity25 litres per min - the cardiac output for a fit male cyclist
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28 beats per min - Miguel Indurain's resting heart rate7.8 litres - Miguel Indurain's lung capacity50 litres Miguel Indurain's cardiac output

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Founded in 1891, Cycling Weekly and its team of expert journalists brings cyclists in-depth reviews, extensive coverage of both professional and domestic racing, as well as fitness advice and 'brew a cuppa and put your feet up' features. Cycling Weekly serves its audience across a range of platforms, from good old-fashioned print to online journalism, and video.