Time-varying Changes in Pulmonary Function with Exposure to Prolonged Sitting

OBJECTIVES The purpose of this study was to quantify the time-varying changes in pulmonary function with exposure to prolonged sitting. METHODS Twenty-one healthy volunteers were recruited. The pulmonary function of all participants was measured three times in order to assess changes over time; pulmonary function was measured before sitting, after participants had been seated for 1 hour, and after they had been seated for 2 hours. A spirometer was used to measure pulmonary function. The recorded values were forced vital capacity, forced expiratory volume in 1 second, ratio of forced expiratory volume in 1 second to forced vital capacity (forced expiratory volume in 1 second/forced vital capacity), and peak expiratory flow. RESULTS All measured values were significantly different before sitting and after 1 hour of sitting. There were also significant differences between all measurements taken before sitting and after 2 hours of sitting. However, the measurements taken after 1 hour and 2 hours of sitting did not significantly differ. CONCLUSION These findings suggest that significant changes in pulmonary function occur relatively quickly when human beings are seated.