Influence of Sitting Posture Including the Position of the Head and Neck on Respiratory Function in Healthy Subjects

Abstract

Respiratory function and cough flow intensity are thought to be influenced by posture. During swallowing training or eating a meal, the postures of the head, neck and trunk are adjusted in a complex manner, but aspiration may still happen even when the posture is suitable. It is important to find the posture that can exhaust aspiration effectively or that allows breathing to be performed easily during a meal.

This study examined posture-related alterations of respiratory function and cough flow intensity in healthy subjects.

The subjects were asked to take four postures in random order: (1) reclining 90 degrees ＋ head and neck facing straight forward (R90HN0), (2) reclining 90 degrees ＋ head and neck tilted 30 degrees in the flexor direction (R90HN30), (3) reclining 30 degrees ＋ head and neck facing straight forward (R30HN0), and (4) reclining 30 degrees ＋ head and neck tilted 30 degrees in the flexor direction (R30HN30). Respiratory function and cough flow intensity parameters included Tidal Volume (TV), Inspiratory Reserve Volume (IRV), Expiratory Reserve Volume (ERV), Vital Capacity (VC), Peak Expiratory Flow (PEF) and Peak Cough Flow (PCF).

As a result, there were no significant differences in TV among the four postures. On the other hand, the measurement items related to labored respiration (IRV, ERV, IC, VC, PCF, PEF) were influenced by posture change. ERV and PCF were significantly greater in the R90 posture than in the R30 posture, and ERV was significantly greater in the HN0 posture than in the HN30 posture.

The R90HN0 posture allowed expiration to be performed most effectively. In other words, it was shown that the R90HN0 posture is the most effective for discharging aspiration.