A system and a method for monitoring activity and posture of a person in correlation with the persons heat activity, comprising a) simultaneously detecting first linear accelerations and first angular speeds of rotation of an upper part of the persons body, second linear accelerations and second angular speeds of rotation of a lower part of the persons body, and the persons electrocardiogram signal and b) determining the persons activity and posture from the first and second linear accelerations, the first and second angular speeds of rotation, and at least one of: i) a derivation signal, ii) heart rate and iii) a respiratory rate, of the person from the electrocardiogram signal.
