Systems and methods for heart disease risk assessment are described herein. An example method may comprise providing a first signal indicative of a heart rate variation (HRV) and respiration of a user, providing a second signal indicative of a HRV, respiration, and motion of the user, continuously determining a state function, wherein the state function depends on the HRV and the respiration, receiving an indication of a change of a body position of the user or a change of external conditions, in response to the indication, determining a shape of distortion of the state function, performing an analysis of the shape of distortion to determine at least one sign of a risk of the heart failure, and providing at least one alert or message regarding the at least one sign of the risk of the heart failure. The state function can include a coherence between the HRV and the respiration.
