There is provided a system (100) for use with a wearable cuff (200) in measuring a physiological characteristic of a subject (300). The system (100) comprises a chamber (102) configured to hold a fluid (104) at a pressure that is greater than atmospheric pressure. The system (100) also comprises a valve and/or a micro pump (106) configured to couple the chamber (102) to the cuff (200). The valve and/or a micro pump (106) is operable to control fluid flow between the chamber (102) and the cuff (200) to increase the pressure in the cuff (200) to a predetermined threshold pressure and vary the pressure in the cuff (200) around the predetermined threshold pressure.
