A fluid-carrying conduit achieves variable resistance to flow. An elongate, hollow body casing has at least one chamber containing either a dilatant fluid or an electroactive polymer. In the case of the dilatant fluid, a reduction in an effective flow cross section of the fluid line occurs in reaction to an increase in the shear rate of a fluid flowing through the fluid line. In the case of the electroactive polymer, a reduction in an effective flow cross section of the fluid line occurs in reaction to an electric current being applied to the body casing. The conduit may be configured for use as a degassing line in a cooling system of an internal combustion engine. The conduit may have a reinforcement encircling the electroactive polymer. The conduit may have an electrically conductive connecting surface adjacent to the electroactive polymer. The electroactive polymer may be an ionic electroactive polymer.