Abstract: Methods of determination of the blood pressure, determination of a heart stroke volume, determination of the state of stress or relaxation of a user, with use of a ballistocardiogram signal reflecting the user's heart beats, with a measure of characteristic amplitude of ballistocardiogram signal, and measure for each couple of consecutive heart beats, beat time intervals DeltaHB(i) between successive heart beats, extracted from a ballistocardiogram signal or from an impedance plethysmography signal measured at the user's foot, leading to determination of a heart rate variability index, over at least six successive heart beats, leading to determination of mean arterial pressure, leading to determination of state of relaxation or stress of the user.