We have developed normal standards for the Bruce exercise (EX) protocol since a review of 875 studies in patients with congenital or acquired heart disease showed that only 5.1% achieved the predicted 50th percentile for EX time of the standards reported by Cumming, Everatt, and Hastman (Am. J Cardiol 41:69, 1978). Our data are based on 160 males and 103 females, age 4–18 years who met the following criteria: trivial or no heart disease, maximal effort, maximal EX heart rate (HR) > 180 beats/min, and normal resting and EX ECG without arrhythmia. The ECG was monitored continuously and HR computed from the ECG and the end of each minute of EX. Comparison with the predicted data of Cumming et al. for each age group by stage showed essentially identical submaximal EX heart rates but slightly lower maximal HR (–2%), which averaged 197 beats per minute in males and females. EX times were on average 15% lower than the predicted 50th percentile for most age groups in males and females. We developed regression equations, which predict exercise time from age and body size or age, body size and 2nd stage exercise heart rate. They better reflect the capabilities of untrained, asymptomatic children and adolescents seen in our laboratory in the 1990s than the Canadian data of 1978.
The authors are with the Division Of Cardiology at The Children’s Memorial Hospital, Chicago, IL 60015.