Out of Sync: How Shift Work Fuels Widespread Sleep Disorders

We often talk about fatigue as if it’s an isolated inconvenience, but large-scale data now show the toll of shift work goes far deeper: curtailed sleep, disordered sleep, and comorbidity of multiple sleep disorders across the board. And the burden isn’t evenly distributed—education, age, and living circumstances change the risk.

This Belgian study (n = 37,662 workers) screened day, early morning, evening, night, and rotating shift workers with the Holland Sleep Disorders Questionnaire. The results confirm what many shift workers already know in their bodies: when your work runs against your circadian clock, sleep fractures.

The signal from the data

Short sleep is the rule, not the exception.

Day workers: ~26% reported ≤6h sleep. Night workers: ~50%. Early and rotating shifts also showed markedly high short sleep.

Long sleep is rare, but clusters in evening workers. (~12%)

Disorders don’t come alone. One in three workers screened positive for at least one sleep disorder. 12.6% screened positive for two or more disorders.

Night shifts are worst. Half reported ≤6h sleep. 51% screened positive for a sleep disorder. 26% screened positive for two or more. Common disorders: insomnia (20%), CRSWD (25%), SRMD such as restless legs/PLMD (23%).

Education matters. Lower education doubled the odds of short sleep and disordered sleep. Night workers with elementary/secondary education showed particularly high vulnerability.

Sociodemographic load. Younger workers (<30) had more insomnia, hypersomnia, parasomnia, and CRSWD. Women reported more disorders overall (insomnia, hypersomnia, parasomnia, CRSWD, SRMD) but less short sleep compared to men. Living alone (with or without children) consistently worsened odds of both short sleep and disordered sleep.

Mechanisms at play

• Circadian misalignment: Sleeping in the biological day (while the body is wired for wake) → insomnia + curtailed sleep. Working in the biological night (when the wake drive collapses) → fatigue, impaired alertness, accident risk.

• Shift Work Disorder (SWD): Seen in ~27% of shift workers; defined by insomnia, excessive sleepiness, or both. Strongly tied to cardiometabolic and mental health consequences.

• Comorbidity cluster: Once circadian disruption sets in, vulnerability to other disorders (restless legs, parasomnias, hypersomnia) seems to increase.

Why this matters

Poor or short sleep isn’t just fatigue—it maps directly to obesity, cardiovascular disease, type 2 diabetes, depression, and substance use disorders. Long sleep, often dismissed, is also tied to higher risk of infectious disease and cardiovascular problems.

Night workers in this dataset mirror what’s seen in clinical cohorts: persistent insomnia and circadian rhythm disorders, sometimes lasting years after night work ends.

Practical takeaways

For shift workers

• Anchor sleep timing where possible. Protect consistent hours even across rotations.

• Light control: Bright light during work, strict dark environment during sleep.

• Sleep hygiene basics: Cool, quiet, tech-free sleep space; avoid alcohol/caffeine before sleep.

• Micro-recovery strategies: Short naps, caffeine timed early, bright light exposure.

• Screen early: If you suspect insomnia, restless legs, or sleep apnea—don’t wait. Treatment prevents chronic decline.

For employers & policymakers

• Favor forward-rotating schedules with limited consecutive nights.

• Build in recovery days and education on circadian biology.

• Support environments for dark recovery sleep and bright workspaces.

• Screen routinely for sleep disorders in high-risk occupations.

• Pay special attention to younger and lower-educated shift workers who show doubled prevalence of disrupted sleep.

Bottom line

This massive dataset confirms: shift work is not just associated with “being tired.” It’s tied to widespread, multi-layered sleep disorders, with night shifts as the most damaging schedule. The signal is strongest for those already vulnerable—young, lower-educated, and socially unsupported workers.

The implication is clear: to prevent decades of downstream disease, we need systematic screening, education, and real structural protections. Night work may be unavoidable in a 24/7 society, but its brain–body costs are not inevitable.

Source: Boersma, G. J., Mijnster, T., Vantyghem, P., Kerkhof, G. A., & Lancel, M. (2024). Shift work is associated with extensively disordered sleep, especially when working nights. PMCID: PMC10755475 | PMID: 38161719.

Author: R.E. Hengsterman, MSN, MA, M.E., RN

Registered nurse, night-shift administrator, and author of The Shift Worker’s Paradox

Nursewhowrites.com

For educational purposes only. Not medical advice.