TY - JOUR

T1 - Physiological responses to four hours of low-level repetitive work

AU - Garde, A Helene

AU - Hansen, Åse Marie

AU - Jensen, Bente R

PY - 2003/12

Y1 - 2003/12

N2 - OBJECTIVES: The study investigated physiological responses to 4 hours of standardized low-level repetitive work. It was hypothesized that accumulative effects not observed after 1 hour could be found after 4 hours of repetitive work.METHODS: Ten healthy women performed intermittent (5 seconds + 5 seconds) handgrip contractions at 10% of the maximal voluntary contraction combined with mental demands for concentration and attention. Muscle activity in the working forearm muscles, cardiovascular responses, and concentrations of biomarkers in biological fluids were recorded along with exerted force, performance, and ratings of perceived physical exertion (RPE), and perceived mental exertion.RESULTS: The urinary epinephrine, norepinephrine, and cortisol concentrations were higher during the repetitive task than on a reference day, but only the norepinephrine concentrations increased progressively during the 4 hours. In accordance, the RPE recorded for the hand, forearm, and shoulder regions increased progressively. For the remaining physiological measures, no accumulative changes were found. Forearm muscle activity was higher during a mental reference task with lower exerted force than during the repetitive task. The variation in exerted force was higher during the repetitive task than during a force reference task without mental demands.CONCLUSIONS: The urinary biomarkers were increased during the repetitive task. However, only norepinephrine increased progressively during the 4 hours. Forearm muscle activity during a mental reference task with low exerted force indicated attention-related muscle activity. Finally, it was indicated that repetitive work including high demands for attention is performed at the expense of the precision of the exerted force.

AB - OBJECTIVES: The study investigated physiological responses to 4 hours of standardized low-level repetitive work. It was hypothesized that accumulative effects not observed after 1 hour could be found after 4 hours of repetitive work.METHODS: Ten healthy women performed intermittent (5 seconds + 5 seconds) handgrip contractions at 10% of the maximal voluntary contraction combined with mental demands for concentration and attention. Muscle activity in the working forearm muscles, cardiovascular responses, and concentrations of biomarkers in biological fluids were recorded along with exerted force, performance, and ratings of perceived physical exertion (RPE), and perceived mental exertion.RESULTS: The urinary epinephrine, norepinephrine, and cortisol concentrations were higher during the repetitive task than on a reference day, but only the norepinephrine concentrations increased progressively during the 4 hours. In accordance, the RPE recorded for the hand, forearm, and shoulder regions increased progressively. For the remaining physiological measures, no accumulative changes were found. Forearm muscle activity was higher during a mental reference task with lower exerted force than during the repetitive task. The variation in exerted force was higher during the repetitive task than during a force reference task without mental demands.CONCLUSIONS: The urinary biomarkers were increased during the repetitive task. However, only norepinephrine increased progressively during the 4 hours. Forearm muscle activity during a mental reference task with low exerted force indicated attention-related muscle activity. Finally, it was indicated that repetitive work including high demands for attention is performed at the expense of the precision of the exerted force.

KW - Adult

KW - Biomarkers

KW - Biomechanical Phenomena

KW - Blood Pressure

KW - Electromyography

KW - Epinephrine

KW - Female

KW - Forearm

KW - Hand

KW - Humans

KW - Hydrocortisone

KW - Muscle Contraction

KW - Norepinephrine

KW - Physical Exertion

KW - Task Performance and Analysis

KW - Time Factors

KW - User-Computer Interface

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

M3 - Journal article

C2 - 14712853

VL - 29

SP - 452

EP - 460

JO - Scandinavian Journal of Work, Environment & Health

JF - Scandinavian Journal of Work, Environment & Health

SN - 0355-3140

IS - 6

ER -