A respiration monitoring device is for use with a signal input and includes a signal interface (624) to receive and convert the signal input to an electronic form for further processing, and an electronic circuit (620) fed by the signal interface (624) and operable to filter in a manner to separate from the acceleration signal a heart signal, to derive a respiration signal from the heart signal, and to subtract the respiration signal from the slow wander signal to produce a substantially non-respiration body motion signal. Other devices, sensor articles, electronic circuit units, and processes are also disclosed.
