In a recent study published in the American Journal of Industrial Medicine, middle aged workers in the U.S. who reported high job strain at the start of the study experienced significantly more sleep disturbances over an average follow-up of nine years.

The study analyzed data from 1,721 workers, with an average age of 51 years, who participated in the Midlife in the United States (MIDUS) study. Sleep disturbances were assessed with an established scale, based on four sleep-related symptoms: trouble falling asleep, waking up during the night and having difficulty going back to sleep, waking up too early in the morning and being unable to get back to sleep, and feeling unrested during the day no matter how many hours of sleep.

The team used six different formulations to quantify job strain based on Karasek's Job‐Demand‐Control model, which defines job strain as a combination of high job demand and low job control. All formulations showed significant associations between higher job strain at baseline and increased sleep disturbances over time.

Our findings also suggest that the continuous formulations of job strain demonstrate better model performance with consistent and robust results, offering empirical evidence for future psychosocial occupational health research in the United States."

Yijia Sun, first author, MS candidate at the University of California, Los Angeles

Corresponding author Jian Li, MD, PhD, a professor of Work and Health at the University of California, Los Angeles, noted that there is an urgent need for workplace interventions to reduce stress. "Strategies such as redesigning workloads and promoting worker autonomy could play an important role in improving sleep health and workers' well-being," he said.

Source:

Journal reference:

Sun, Y., et al. (2025) Alternative Formulations of Job Strain and Sleep Disturbances: A Longitudinal Study in the United States. American Journal of Industrial Medicine. doi.org/10.1002/ajim.23686.