Science Behind Emfit
EMFIT products rely on ballistocardiography and detecting breathing and other body movements.
"Ballistocardiography - Technique of graphic representation of the movements of the body imparted by the ballistic forces (recoil and impact) associated with cardiac contraction and ejection of blood and with the deceleration of blood flow through the large blood vessels. These movements, quantitatively very minute, are translated by a pickup device (transducer) into an electrical potential which is suitably amplified and recorded on a conventional electrocardiograph or other recording machine." Explanation by courtesy of National Library of Medicine (NLM).