A method for continuous calibration of a blood pressure measurement device, comprising: determining, by a processor, whether a change in a measurement of the distension and/or cross sectional area of an artery of a patient as measured by a non-interfering blood pressure measurement device and elevation of the non-interfering blood pressure measurement device both occurred between two observation times; determining, by the processor, whether a change in pulse rate has occurred between the two observation times in response to determining that a change in a measurement of the distension and/or cross sectional area of the artery as measured by the non-interfering blood pressure measurement device and elevation of the non-interfering blood pressure measurement device both occurred between two observation times; determining, by the processor, in response to determining that no change in pulse rate occurred between the two observation times: (i) an incremental variation of the measured distension and/or cross sectional area and (ii) the elevation between the two observation times; determining, by the processor, coefficients fitting an exponentially decaying function representing an exponential decay of a portion of a diastolic phase of a pulse, wherein the coefficients comprise (i) a distension amplitude of a diastolic part of the pulse between the two observation times and (ii) a bias term; determining diastolic pressure by multiplying the exponentially decaying function with the incremental variation between the two observation times; determining, by the processor, a current mean arterial pressure based on a mean of pulse pressures from a start of a systole to an end of a diastole, wherein said mean is scaled with the incremental variation and with the bias term; determining, by the processor, whether a change in mean arterial pressure is greater than a threshold value based on a comparison of the determined current mean arterial pressure and a previously determined mean arterial pressure; and calibrating, by the processor, the non-interfering blood pressure measurement device in response to determining that the change in mean arterial pressure is greater than the threshold value. determining, by a processor, whether a change in a measurement of the distension and/or cross sectional area of an artery of a patient as measured by a non-interfering blood pressure measurement device and elevation of the non-interfering blood pressure measurement device both occurred between two observation times; determining, by the processor, whether a change in pulse rate has occurred between the two observation times in response to determining that a change in a measurement of the distension and/or cross sectional area of the artery as measured by the non-interfering blood pressure measurement device and elevation of the non-interfering blood pressure measurement device both occurred between two observation times; determining, by the processor, in response to determining that no change in pulse rate occurred between the two observation times: (i) an incremental variation of the measured distension and/or cross sectional area and (ii) the elevation between the two observation times; determining, by the processor, coefficients fitting an exponentially decaying function representing an exponential decay of a portion of a diastolic phase of a pulse, wherein the coefficients comprise (i) a distension amplitude of a diastolic part of the pulse between the two observation times and (ii) a bias term; determining diastolic pressure by multiplying the exponentially decaying function with the incremental variation between the two observation times; determining, by the processor, a current mean arterial pressure based on a mean of pulse pressures from a start of a systole to an end of a diastole, wherein said mean is scaled with the incremental variation and with the bias term; determining, by the processor, whether a change in mean arterial pressure is greater than a threshold value based on a comparison of the determined current mean arterial pressure and a previously determined mean arterial pressure; and calibrating, by the processor, the non-interfering blood pressure measurement device in response to determining that the change in mean arterial pressure is greater than the threshold value.