A nasal insert includes a housing having a circumferential wall defining an interior passage. The wall has a longitudinal gap extending along a length thereof, with an outer peripheral dimension of the housing being adjustable by varying the gap. A valve is in communication with the interior passage and limits a fluid flow through the interior passage in at least one direction. In another embodiment, a nasal insert includes a user interface having a tubular housing defining an interior cavity open at opposite ends. An exterior surface of the housing is adapted to interface with a nasal vestibule of a user. A base is received in the interior cavity of the housing and includes an exit port. A cap is connected to the base and has an input port. A valve member is disposed in an interior passage defined by at least one of the cap and base, with the valve member being moveably received in the interior passage. Methods of using and assembling the nasal inserts also are provided.
