Abstract: A device for exercising respiratory muscles. By creating a cavity within its bottle like body, the device is able to trap a sufficient amount of exhaled CO.sub.2, to prevent a subject from experiencing the effects of hyperventilation as the subject inhales and exhales at high and large respiratory rates and volumes respectively. The invention has at one end a face mask, which is fastened to a bottle like body. This bottle like body can be enlarged or reduced to create a varying size cavity that traps exhaled CO.sub.2 and ambient air. An opening is placed at or near the bottom of the device that allows ambient air to enter the cavity. The opening is large enough so that no resistance of air flow is experienced during breathing exercise, as resistance of air flow may be damaging to lung tissue. The bottle like body which creates the cavity is divided into upper and lower halves.

Abstract: A pulmonary valve for use with fitness level respiratory testing equipment, having a tubular silicone rubber body member. Formed at one end of this member is a mouth seal which is subsequently inserted into a subjects mouth. In the superior surface of the tubular body member is found the inhalation ports, these ports allow for air passage during inhalation. Within the tubular body member is housed two valve membranes, one for inhalation and one for exhalation. During inhalation, the inhalation membrane opens, creating an airflow passage-way directly to a subjects's mouth cavity. During exhalation the inhalation membrane closes shut and the exhalation membrane opens thus creating a second and separate airflow passage-way, at the end of exhalation the exhalation membrane closes shut, thus completing one respiration cycle. Because of the unique membrane design there is found no equipment dead space.