Measurement of Human Heart Rate during Usual Activty

Science  16 Oct 1959:
Vol. 130, Issue 3381, pp. 976-977
DOI: 10.1126/science.130.3381.976


A small, rugged, self-contained cumulative heart-beat counter has a transistorized amplifier, a watch movement made into a counter, and a battery. The counter is activated by each R-wave of the electrocardiographic complex obtained from newly designed precordial electrodes. Heart beats can be counted for as long as 24 hours.