Effect of attention demand on upper trapezius muscle activity – A moderated mediation model

Manufacturing continues to become more automated. Consequently, production operators are monitoring automated processes for prolonged durations. The sustained attention required for monitoring work has been was found to be stressful for humans. This study hypothesises that sustained attention is a psychosocial stressor that increases upper trapezius muscle activity via a psychophysiological pathway in a series of simulated industrial tasks. A moderated mediation model was tested and accepted with the parasympathetic nervous system acting as a mediator contingent on certain levels of end-tidal CO₂. The study outcomes confirmed that sustained attention acts as a psychosocial stressor which increases upper trapezius muscle activity by inhibiting the action of the parasympathetic system and increasing hyperventilation.