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Related Experiment Video

Updated: May 21, 2026

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments

Published on: August 8, 2019

Work hours and cortisol variation from non-working to working days.

Alain Marchand¹, Pierre Durand, Sonia Lupien

¹School of Industrial Relations, University of Montreal, C.P. 6128, Succ Centre-ville, Montreal, QC, H3C 3J7, Canada. alain.marchand@umontreal.ca

International Archives of Occupational and Environmental Health

|June 12, 2012

Summary

Longer work hours increase stress, as indicated by higher cortisol levels on workdays. Non-working days help reduce this work-related stress for employees.

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Published on: June 18, 2014

Area of Science:

Occupational Health
Endocrinology
Psychology

Background:

Work hours are a significant factor in occupational stress.
Cortisol levels are a key biomarker for physiological stress response.
Understanding the diurnal cortisol variation in relation to work demands is crucial for employee well-being.

Purpose of the Study:

To model the relationship between weekly work hours and cortisol variation.
To compare cortisol levels on working days versus non-working days.
To investigate these relationships in a population of day-shift workers.

Main Methods:

Collected questionnaire data and saliva samples from 132 day-shift workers across 13 Canadian workplaces.
Measured salivary cortisol 5 times daily (upon waking, 30 min after, 2 PM, 4 PM, bedtime) on Saturday, Tuesday, and Thursday.
Utilized multilevel regression models to analyze cortisol measurements nested within days and workers.

Main Results:

Significant variations in salivary cortisol were observed across sample, day, and worker levels.
Cortisol concentration increased linearly from non-working to working days.
A positive association was found between weekly work hours and cortisol concentrations on working days.

Conclusions:

Work hours function as a stressor, significantly impacting cortisol levels during working days.
Non-working days appear to mitigate stress for workers with longer work hours.
These findings highlight the importance of work-life balance for managing occupational stress.