The effects of a defecation posture, supported by the upper limbs, on respiratory function

[Purpose] In this study, we aimed to determine which typical postures or an arm-supported posture were more comfortable and conducive to respiratory function, during seated defecation. [Participants and Methods] In 73 healthy adults, we measured and compared respiratory function and subjective contentment associated with 3 sitting defecation postures: upright, forward-leaning, and arm-supported forward-leaning. [Results] Vital capacity (VC), forced vital capacity (FVC), maximal expiratory pressure (MEP), and subjective comfort were significantly greater in the arm-supported forward-leaning position than in the other 2 positions. [Conclusion] The arm-supported forward-leaning position for defection increased the VC and was subjectively comfortable. Moreover, the high MEP in this position, compared with the other 2 positions, may have facilitated strain. A detailed examination of the cause for the observed increase in comfort was beyond the scope of this study; therefore, this effect requires further investigation.