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Breathing patterns and heart rate during simulated occupational upper limb tasks in normal subjects
Author(s) -
Mackey Martin,
Ellis Elizabeth,
Nicholls Max
Publication year - 1998
Publication title -
physiotherapy research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.509
H-Index - 49
eISSN - 1471-2865
pISSN - 1358-2267
DOI - 10.1002/pri.128
Subject(s) - work of breathing , torso , medicine , functional residual capacity , plethysmograph , breathing , respiratory minute volume , workload , physical medicine and rehabilitation , ventilation (architecture) , respiratory system , respiratory rate , lung volumes , tidal volume , work (physics) , muscles of respiration , sitting , cardiology , physical therapy , heart rate , anesthesia , lung , anatomy , computer science , blood pressure , mechanical engineering , pathology , engineering , operating system
Background and Purpose Despite the arms being used extensively in the performance of many occupational tasks, little is known about the pattern of breathing and physiological cost of such work. The purpose of this study was to establish whether a simple change in arm support could alter the workload, pattern of breathing and respiratory muscle recruitment during a low intensity arm task. Methods Ten normal subjects performed a simulated work task when sitting, once with the arms supported and once unsupported. Subjects were required, over a five‐minute period, to repeatedly pick up a 2 kg object, inspect and hold it for 15 seconds and then pack it in a box. Breathing pattern responses, measured by pneumotachograph and respiratory inductive plethysmography, were minute ventilation (V E ), respiratory frequency (Rf), tidal volume (V T ) and change in functional residual capacity (FRC). Results The main findings were that unsupported arm work was more physiologically demanding than supported arm work. During work V E increased as a result of a change in respiratory frequency but not V T which was much more limited when the arms were unsupported. At the completion of activity, when the arms were unloaded, V T initially increased as V E decreased. FRC and V T were reduced during arm work and increased during recovery, mainly as a result of a change in ribcage excursion. Conclusions These findings support the theory that during arm activity, intercostal and accessory respiratory muscles act to stabilize the arms and torso, impeding chest wall movement and shifting the respiratory load from these muscles to the diaphragm. This may adversely effect performance of workers who have ventilatory limits to arm work tasks. Copyright © 1998 Whurr Publishers Ltd.