Systems, methods, and devices of the various embodiments enable continuous non-invasive monitoring of blood pressure with a minimum of interference. The various embodiments may provide a method for adaptation for the calibration for continuous measurements of blood pressure, wherein the measured quantity may be related to an arterial lumen or arterial cross sectional area comprising calibrating the conversion for incremental variations of arterial properties and absolute value adaptation by exploitation of the exponential decay during the diastole. In various embodiments, continuous calibration of a non-interfering blood pressure measurement device may be initiated based on a change in mean arterial pressure being greater than a threshold value, such as a pressure value associated with an actual measured distension of a patient's artery.