Night shifts and chronic sleep deprivation are associated with a significantly higher risk of long COVID. That is the finding of a study reported by the German trade publication Haufe Arbeitsschutz. Researchers mapped how disruptions to the body’s internal clock — the so-called circadian rhythm — are linked to persistent symptoms following a coronavirus infection. The findings touch on an issue of global relevance: millions of workers in healthcare, industry, transport and hospitality work night shifts on a structural basis.
What does the research show?
The researchers followed people who were infected with SARS-CoV-2 between 2021 and 2023. Long COVID was defined as symptoms persisting more than three months after infection. Of the nearly two thousand participants, a substantial share developed such persistent symptoms.
Night work alone was associated with an 88 percent higher risk of long COVID compared with daytime work. Chronic insomnia — independent of shift work — was linked to a 42 percent higher risk. Workers who both worked nights and struggled with persistent sleep problems faced an almost 2.7 times higher risk. For those who worked at least three night shifts a month, the risk was just over twice as high as for day workers.
What does this mean for employers?
In the study, night work was not associated with a higher chance of becoming infected. According to the researchers, the pattern therefore points more to slower or less complete recovery after an infection: a disrupted circadian rhythm appears to mainly affect how well the body recovers and whether symptoms become chronic, not susceptibility to infection itself. For employers in sectors with extensive shift work — from hospitals to logistics centres — this is a signal to pay attention to sleep quality and schedule design: predictable shifts, sufficient recovery time between night shifts and easy access to sleep guidance could help reduce absenteeism. The researchers themselves emphasise that healthy sleep and limiting night-shift burden may be effective strategies for reducing the consequences of long COVID.
Context
The reporting refers to a study published in the scientific journal Scandinavian Journal of Work, Environment & Health, by researchers affiliated with the Medical University of Vienna (Austria) and the Barcelona institute ISGlobal. They analysed data from 1,899 participants in the Spanish COVICAT cohort (2021-2023); more than 280 of them (about 15 percent) developed long COVID, with neurological symptoms predominating (54 percent of cases), followed by muscular and respiratory symptoms. The researchers themselves point out that the associations found — especially in smaller subgroups, such as people with obesity — should be interpreted with caution: this is an observational cohort study that demonstrates a statistical association, not a proven causal mechanism.
Source: How shift work and sleep deprivation increase the risk of long COVID, 2 October 2026
Additionally researched: the underlying study in Scandinavian Journal of Work, Environment & Health (COVICAT cohort study, Medical University of Vienna / ISGlobal) and reporting by CIDRAP (University of Minnesota) on the same research.
