Medical tubes and methods of manufacturing medical tubes are disclosed, such as in positive airway pressure (PAP), respirator, anaesthesia, ventilator, and insufflation systems. The tube may be a composite structure made of two or more distinct components spirally wound to form an elongate tube. One of the components may be a spirally wound elongate hollow body, and the other component an elongate structural component spirally wound between turns of the spirally wound hollow body. Alternatively, the tube need not be made from distinct components. For instance, an elongate hollow body formed (e.g., extruded) from a single material may be spirally wound to form an elongate tube. The elongate hollow body itself may in transverse cross-section have a thin wall portion and a relatively thicker or more rigid reinforcement portion. The tubes can be incorporated into a variety of medical circuits or have other medical uses.