A resistance breathing device includes a face mask having a perimeter and an aperture extending therethrough, and being adapted to overlay a users mouth and nose such that the perimeter forms an air-tight seal with the users face. An overlaying outer layer has a pair of straps for affixing the face mask about the users face. An adjustment slide is positioned adjacent the face mask, has an inlet aperture extending therethrough, and is movable between a first position in which a first portion of the inlet aperture overlaps the inlet aperture of the face mask and a second position in which a larger second portion of the inlet aperture overlaps the inlet aperture of the face mask. An adjustment wheel is attached to the face mask and is movable rotatably between first and second positions to cause the adjustment slide to move between its first and second positions.
