In determining respiratory muscle strength, mouth pressure measurement is most frequently used in the clinic. Determination of respiratory muscle strength loss provides benefits such as taking the decision to use individual rehabilitation methods, making the decision for extubation in patients with mechanical ventilation. But Turkey normative values, these values are not available. In the investigator's country, the respiratory muscle forces of the cases are evaluated by comparing them with the normal / expected values of the Scandinavian races that do not have similar anatomical features with the Turkish society, which causes errors in diagnosis.

The 250 healthy cases, whose age ranges are between 20-70, 20-29, 30-40, 40-49, 50-59 and 60-70, will be examined by a pulmonologist and asked if they have any disease that may affect respiratory muscle strength. Mouth pressure measurements will be made for healthy and inclusion criteria, and maximal inspiratory and expiratory pressure distributions will be examined.

Inclusion Criteria:

• The age range is 20-70,
• Body mass index to be 18.0- 29.5 kg / m2
• No cardiac, neuromuscular or endocrine disease that may affect any respiratory muscle strength Respiratory function parameters to be normal,
• Not being a smoker

Exclusion Criteria:

• Not agreeing to participate in the study
• Not being able to adapt to the device

Healthy adults