A gases transportation pathway (2) for use in supplying a humidified gases stream to a patient includes regulated conduit heating (12). The regulated conduit heating (12) includes a layer of positive temperature coefficient material within the wall of the gases transportation pathway (2) wherein the localised electrical resistance of the material is positively related to the localised temperature. At least a pair of conductors (21,22) running the length of the pathway and in electrically conductive contact with the positive temperature coefficient material.
