Yield of ischaemic exercise electrocardiograms in relation to exercise intensity in a normal population.

Maximal bicycle ergometer exercise in an asymptomatic male population, aged 40-65 years, revealed 63 subjects with 'ischaemic' ST changes. The work intensity at the time of appearance of this change was expressed as actual heart rate as a per cent ofmaximum heart rate, and oxygen uptake as a per cent ofmaximal oxygen uptake. If the exercise had been stopped at a target heart 'rate of 85 per cent of expected maximum heart rate, half of the abnormal responses would have been missed. The evidence favours the use of a graded exercise test proceeding to the point of voluntary fatigue. The ischaemic change was noted only during andlor after a supermaximal exercise load in 27 per cent of the subjects.