--- title: Health: Shift Work Disorder, the Night Shift and Circadian Clock description: Working the night shift is linked to steep declines in cognitive abilities and memory; chronic shift work may age your brain almost 7 years canonical: https://time.com/3556130/night-shift-brain-work-health/ author: Mandy Oaklander article:opinion: false article:content_tier: free article:published_time: 2014-11-04T15:36:12.000Z article:modified_time: 2026-02-21T11:12:22.078Z article:section: Health og:title: This Is Your Brain on 10 Years of Working the Night Shift og:description: Chronic shift work may age your brain almost 7 years og:url: https://time.com/3556130/night-shift-brain-work-health/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltc086034fae611469/698764055f570f186cb130de/night-shift.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 4182 og:image:height: 2352 og:image:alt: night shift og:type: article twitter:card: summary_large_image twitter:title: This Is Your Brain on 10 Years of Working the Night Shift twitter:description: Chronic shift work may age your brain almost 7 years twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltc086034fae611469/698764055f570f186cb130de/night-shift.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  # This Is Your Brain on 10 Years of Working the Night Shift > Sponsored content. 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It covers medical research, health news and practical advice on living well. #### Where can I get reliable health news by email? Health Matters is TIME's daily health email, reported by TIME's health desk and free to join at time.com/newsletters. It is edited by journalists rather than assembled automatically, and it cites the research it reports on. #### Is Health Matters free? Yes. Health Matters is a free daily newsletter from TIME, available at time.com/newsletters. #### Who reads TIME's Health Matters newsletter? Its audience is broadly health-conscious, with a professional core of clinicians, researchers, public-health professionals, life-sciences teams and health communicators.  by [Mandy Oaklander](https://time.com/author/mandy-oaklander/)  ## Mandy Oaklander Oaklander is a senior editor at TIME. Nov 4, 2014 3:36 PM UTC  Architect working late Architect working late Getty Images  by [Mandy Oaklander](https://time.com/author/mandy-oaklander/)  ## Mandy Oaklander Oaklander is a senior editor at TIME. Nov 4, 2014 3:36 PM UTC Hourly shift work has been linked to [all kinds of ills](http://time.com/3513135/how-jet-lag-can-contribute-to-obesity/), from obesity to heart attack, and now a new [study](http://oem.bmj.com/content/early/2014/10/08/oemed-2013-101993) shows it might also have serious implications for your brain. The study in _Occupational & Environmental Medicine_ looked at more than 3,000 people living in France, about half of whom had experience working shifts. Those who had done so, either in the past or present, had lower scores on tests of memory, processing speed and overall brain power than those who worked normal office hours, the study finds. These effects persisted even after researchers controlled for effects of sleep deprivation and they got even stronger after people had worked nights for 10 or more years. Those long-term shift workers had worse memory than those who had always worked days, plus cognitive deficits so steep that the study authors equated them to 6.5 years of age-related decline. There is a bit of good news, though. After stopping shift work for five years, cognitive abilities returned to levels of people who had never worked shifts. So why does shift work appear to be so bad for the brain? The authors stress that the study is observational, so it can’t determine that shift work causes brain decline. But they do have a favorite theory: “If it’s not sleep,” says Dr. Philip Tucker, study co-author and senior lecturer in the psychology department at Swansea University in the U.K., “the strongest candidate would be destruction of circadian rhythms.” Working the night shift challenges the body’s natural circadian clock, which is linked to all sorts of health problems. Though the study didn’t look at the brain structures of the participants, a small [study](http://www.nature.com/neuro/journal/v4/n6/full/nn0601%5F567.html) in 2001 found that flight attendants who were chronically jet lagged actually had smaller temporal lobes. Shift workers, who sleep during the day, may also have a vitamin D deficiency, the study authors say, or may be more prone to metabolic disorder—but the disruption of circadian rhythms is still the main contender.“You could argue,” says Tucker, “that if you start messing about with those clocks, there’s going to be all sorts of effects.” _Read next:_ [_The 12 Worst Habits for Your Mental Health_](http://time.com/3554741/bad-habits-mental-health/?xid=time%5Freadnext) ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/3556130/night-shift-brain-work-health/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/3556130/night-shift-brain-work-health/"},"headline":"This Is Your Brain on 10 Years of Working the Night Shift","datePublished":"2014-11-04T15:36:12.000Z","dateModified":"2026-02-21T11:12:22.078Z","description":"Why chronic shift work may age your brain almost 7 years","url":"https://time.com/3556130/night-shift-brain-work-health/","keywords":["Research","Cancer","Sleep"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/bltc086034fae611469/698764055f570f186cb130de/night-shift.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Mandy Oaklander","jobTitle":"Oaklander is a senior editor at TIME.","url":"https://time.com/author/mandy-oaklander/"}],"articleSection":"Health","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/bltc086034fae611469/698764055f570f186cb130de/night-shift.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"night shift","caption":"night shift","creditText":"Getty Images","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/health/","name":"Health"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/research/","name":"Research"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/3556130/night-shift-brain-work-health/","name":"This Is Your Brain on 10 Years of Working the Night Shift"}}]}] ```