Validity of the Postexercise Heart Rate as a Means of Estimating Heart Rate during Work of Varying Intensities

To determine the validity of the postexercise heart rate as a means of estimating the rate during work, heart rate was recorded at various intervals during recovery from light, moderate, and strenuous work. The error in estimating the exercise heart rate from readings taken during the 10 seconds immediately following strenuous work (180 beats/min.) averaged 2.7%. This increased to 7.6% during the first 10 seconds of recovery from exercise rates of approximately 140 beats / min. If one allowed approximately 4 seconds to locate the pulse and then counted during a 10-second interval, the average underestimation of the exercise heart rate increased to 5.7% in strenuous work and 13.5% in recovery from more moderate exercise. The rate of recovery is not similar for all individuals. This variability may introduce serious errors when the postexercise heart rate is used to infer the heart rate during exercise.