Paper published by Swiss researchers about respiratory rate estimation during running using the Polar H10 heart rate monitoring system You can use the Polar H10 when an accuracy of more than 5.5% is not required: https://mdpi-res.com/d_attachment/sensors/sensors-21-05651/article_deploy/sensors-21-05651-v2.pdf You don t have to read all the papers of Peter H. Charlton and his PhD thesis, if you …