Effect of sitting posture on respiratory function while using a smartphone

[Purpose] The purpose of this study was to investigate respiratory function in different sitting postures while using a smartphone. [Subjects and Methods] Fifty healthy volunteers were recruited. Participants were divided into 2 groups, a control group of participants who spent time as they liked for 1 hour, and a smartphone group of participants who spent time using a smartphone in a sitting position for 1 hour. To investigate changes in respiratory function, we measured forced vital capacity, forced expiratory volume in 1 second, ratio of forced expiratory volume in 1 second to forced vital capacity, and peak expiratory flow. [Results] There was a statistically significant difference in forced vital capacity and forced expiratory volume in 1 second between the control group and smartphone group. [Conclusion] The clinical implication of our findings is that the posture assumed while using a smartphone leads to reduced respiratory function.