Night Shift Work Accelerates Aging and Reduces Life Expectancy by Nearly One Year

Night shift work has long been suspected of harming health, but this large-scale study provides concrete evidence of its impact on aging and longevity. Researchers analyzed data from 192,764 UK Biobank participants to understand how night work affects biological aging processes.

The study measured biological aging using two validated methods: KDM-BA and PhenoAge, which assess how fast someone is aging based on blood biomarkers and physical measurements rather than chronological age. Night shift workers showed significantly accelerated biological aging on both measures compared to day workers.

Most striking was the life expectancy finding: usual night shift workers lost nearly a full year of life expectancy by age 45. The effects followed a dose-response pattern, meaning more frequent and longer-duration night shifts caused progressively worse aging acceleration. This relationship held across different demographic groups and remained strong even after accounting for other health factors.

The researchers identified body weight as a key mediator, explaining 29-43% of the association between night work and accelerated aging. This suggests that night shift workers who maintain healthy weight might partially offset some aging effects, though the underlying circadian disruption likely still causes harm.

These findings have important implications for the millions of people working night shifts in healthcare, manufacturing, and service industries. While some night work may be unavoidable, the results suggest minimizing exposure when possible and focusing on weight management as potential protective strategies.