During maximal exercise, a 75 kg athlete aged 25 would have a

A. True The predicted rate (220 minus age in years) is 195.

B. False A heart rate of 195 and stroke volume of 70 would give a cardiac output of 13.65 litres/minute; maximal output in an athlete is about twice that value.

C. True A tidal volume of 2 litres and respiratory rate of 60/minute gives a total ventila-tion of 120 litres/minute.

D. False It should be five to ten times the resting level.

E. True It would be below 100 ml/litre (less than 50 per cent saturated); most of the cir-culation passes through exercising muscles and gives up considerably more than half its oxygen to the muscles.