Stress reactions to cognitively demanding tasks and open-plan office noise

Int Arch Occup Environ Health (2009) 82:631641 DOI 10.1007/s00420-008-0367-4

ORIGINAL ARTICLE

Stress reactions to cognitively demanding tasks and open-plan oYce noise

Jesper Kristiansen Line Mathiesen Pernille Kofoed Nielsen se Marie Hansen Hitomi Shibuya Helga Munch Petersen Sren Peter Lund Jrgen Skotte Marie Birk Jrgensen Karen Sgaard

Received: 20 December 2007 / Accepted: 29 September 2008 / Published online: 21 October 2008 Springer-Verlag 2008

Abstract

Objectives To investigate the eVects of cognitively demanding work tasks and oYce noise on heart rate variability (HRV), cardiovascular responses and electromyography (EMG) activity in the trapezius muscles.

Methods Ten female volunteers were exposed to simulated open-plan oYce noise for 35 min (Leq 65 dBA), while engaged in cognitively demanding tasks. Task performance, self-rated stress and energy, aVective state, perceived exertion in the shoulders and in the head, EMG in the left and right trapezius muscle, blood pressure, heart period length, HRV, and salivary cortisol were measured. Results Cognitively demanding work tasks were associated with changes in HRV, systolic blood pressure and EMG that reXects increased sympathetic activity in the autonomic nervous system. No eVect of noise was observed, except for a higher rating of perceived exertion in the head and, contrary to expectations, a 4% lower diastolic blood pressure in the noise conditions.

Conclusions Psychophysiological measures reXected the mental load imposed by cognitive work tasks. Short-term exposure to oYce noise resulted in increased ratings of perceived exertion in the head, but not in physiological stress reactions.

Keywords Work-related stress OYce work Mental load Cognitive demands

Introduction

Stress reactions associated with cognitively demanding tasks simulating the conditions of oYce work and/or computer-based work have been addressed in a number of studies. For example, cognitive work tasks have been combined with time pressure and verbal provocation (Wahlstrm et al. 2002), memory demands (Finsen et al. 2001a, b) and psycho-social stressors (Hjortskov et al. 2004). In general, these studies have all demonstrated that the combined eVect of the work tasks and the stressors elicit cardiovascular responses that exceed the response imposed by the cognitive tasks alone. Moreover, the cardiovascular reactions are paralleled by increased electrical activity in various muscles in the arms and shoulders (Finsen et al. 2001a, b; Wahlstrm et al. 2002). It has therefore been hypothesized that the combined load of...