Examples of the disclosure relate to apparatus for sensing biometric parameters and methods of forming the apparatus. The apparatus may comprise one or more sensors configured to sense one or more biometric parameters from a subject's sweat. The apparatus may also comprise heat transfer means configured to transfer heat from a first location to a location proximate to the one or more sensors. The heat transfer means may therefore provide localized heating within the region of the one or more sensors. The apparatus could be provided within a wearable device.
