A method of deriving mean arterial pressure of a subject is disclosed. The method comprises (i) receiving (202) data relating to at least one cardiac cycle of a bio signal from the subject (ii) normalizing the received data relating to the at least one cardiac cycle (iii) calculating (206) an area enclosed by the normalized received data to obtain a normalized area (iv) calculating (208) a heart rate of the subject from the at least one cardiac cycle and (v) deriving (210) the mean arterial pressure from the normalized area and heart rate. A related apparatus is also disclosed.
