A method, apparatus and computer program, in which a body of a wearable apparatus is maintained maintaining by a link in place at a given part of skin of the user. A sensor platform is movably supported sandwiched between the body and the skin and supported by the body movably with relation to the body towards and away of the skin, when the apparatus is worn by the user. A sensor is supported by the sensor platform. The sensor produces sensor signals corresponding to a property of the skin or underlying matter. The position of the sensor platform is adjusted by an actuator with relation to the skin.