A portable heart rate distribution recorder for studying daily physical activity.

This paper provides a brief description of a new 8-register heartbeat integrator for recording the heart rate over a long period (24-h or more) in order to assess daily physical activity in children and adults. This compact, rugged device records the cardiac beat to beat interval in seven registers, ranging from 40--225 H4/min. An eight register, the so called "quality level"; (range 225--300 Hr/min) is added to count all non-physiological pulses resulting from muscle noise, etc. To test for validity this system was evaluated simultaneously against two established systems; a manual acoustic monitoring system and a heart rate recording system. Comparison of the results demonstrated good agreement. Integrator influences on the normal daily activity behaviour of the children (age 5 yrs.) was checked with the pedometer method. It was found that wearing of the heartbeat integrator did not appreciably influenced the normal behaviour of the children.