Similar lengths of corrugated stretch hose are components used to form a tube-in-tube breathing circuit assembly having a smaller diameter inner hose that extends loosely through a larger diameter outer hose. Overlying end regions of the inner and outer hoses are joined by connectors that communicate separately with each of the inner and outer hoses near opposite ends of the assembly. Exhaled breath from a patient that travels through the outer hose warms breathing gas supplied to the patient through the inner hose. In one form of preferred practice, the inner hose draws taut regardless of the extent to which the breathing circuit assembly may be extended, retracted and bent, which minimizes resistance to flow through each of the two hoses.
