A wrist-mounted arterial pulse interval and movement recording system

A wrist movement and arterial pulse interval recording system has been developed for continuous data acquisition in studies of activity/rest time ratios, sleep quantity and quality, general activity level, resting heart rate and circadian rhythms. The system employs a wrist-mounted piezoelectric sensor, a low-power 8-bit one-chip microcomputer and a 512 KB EEPROM. The microcomputer detects whether the wrist is moving or inactive; if it is moving, wrist movement is stored into memory. If the wrist is at rest, the arterial pulse interval is continuously detected and stored. After recording, these stored data are downloaded to a desktop computer and analyzed.