There is provided a nasal
dilator (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 130) for treating respiratory problems comprising a hollow nasal
dilator body (1000, 1400a, 1400b, 1800, 1900, 2000, 2500, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 9000a, 9000b, 9000c, 9000d) and a unidirectional flow resistance unit. The hollow nasal
dilator body (1000, 1400a, 1400b, 1800, 1900, 2000, 2500, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 9000a, 9000b, 9000c, 9000d) has a first open end (1001, 2001, 2501, 3001, 4001, 5001, 9001, 9001a, 9001b, 9001d) and a second open end (1002, 2002, 2502, 3002, 4002, 5002, 9002, 9002a, 9002b, 9002d) opposed to one another and is suitable for
insertion into a user's
nasal cavity. The second open end (1002, 2002, 2502, 3002, 4002, 5002, 9002, 9002a, 9002b, 9002d) can be positioned within the user's
nasal cavity to support and dilate the
nasal cavity. The one-way flow resistance unit is assembled to the hollow nasal dilator body (1000, 1400a, 1400b, 1800, 1900, 2000, 2500, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 9000a, 9000b, 9000c, 9000d), and the user's expiratory flow resistance is higher than the
inhalation flow resistance such that an expiratory
positive airway pressure is generated in the user's nasal cavity.