Analysis of the pulmonary functions of normal adults according to pillow height

[Purpose] The purpose of this study is to examine changes in pulmonary functions in relation to the sleeping positions of the experimental subjects. [Subjects and Methods] The subjects for this study were twenty randomly selected males and females from K University. Measurements were taken in the supine position at three different pillow heights: 0 cm, 5 cm, and 10 cm. Pulmonary functions (vital capacity, tidal volume, inspiratory reserve volume, and expiratory reserve volume) were evaluated using a Fit mate. [Results] These findings suggest that a pillow height of 5 cm makes a significant difference in vital capacity (VC). When the three pillow heights were compared, significant differences were seen between 0 cm and 5 cm, and between 5 cm and 10 cm, in terms of vital capacity for the pulmonary functions among the three positions. [Conclusion] In conclusion, changing the positions of the subjects produces changes in pulmonary functions. The greatest change occurred in the 5 cm pillow height. Presumably, ventilation is affected by the body structures. The results will provide objective data to establish the most suitable positions for stroke patients when they perform respiratory exercises.