In brief: Ten men and four women were studied to compare two devices for measuring heart rate: a microcomputer worn on the wrist and an ECG. The subjects performed exercise tests on a bicycle ergometer and/or a treadmill; heart rate was monitored during and after exercise. Heart rates recorded by the microcomputer during exercise were frequently higher than those measured at the same time by ECG. However, the two methods differed at most by only 5 beats min1, which was not considered statistically significant. The authors found both methods equally suitable for measuring heart rate during and after exercise and for analyzing intensity of training.