Monitoring physiological signals during running exercise

An ambulatory monitoring device for the measurement of heart rate, step rate and respiration signals of human subjects during running exercise is described. The monitor which is fixed on an elastic belt can be worn around the subject´s chest. A new Microchip PIC16F876-20 8 bit Flash Programmable Microcontroller with built-in A/D converters is used to sample analogue signals and transmit them wirelessly to a computer via RF transceivers. With 2.4 GHz frequency hopping spread spectrum technology, the RF transceivers provide immunity to jamming as well as multi-path fading. The transmission power is 100 mW that covers a range of approximately 1 km line-of-sight. The monitor can also receive data from the computer for adjusting analogue circuit parameters and provide an audio click sound to the subject as a step reference signal through an earphone. It is hoped that, in the future, this ambulatory device will contribute to research studies on human performance during running exercise.