Night shift work causes chaos in the body as the central ‘clock’ in the brain doesn’t reboot, but other clocks in various organs like the liver do, creating conflict between metabolites leading to a disrupted metabolism.
Night shift work has been previously linked to metabolic disease – such as obesity, high blood pressure and higher cholesterol and blood sugar, and even cancer.
This research (1) aimed to show ‘why’. We have a normal Circadian rhythm, built over time to go to sleep when it gets dark. In this study, the researchers found that switching to night shift work did not see an immediate change in the body’s circadian rhythm. This is because our organs have internal clocks. Yes, really. And these clocks are normally in sync with a centralised ‘master’ clock in the brain – the ‘suprachiasmatic nucleus’.
The problem is that the master clock doesn’t alter. But the team also analysed the metabolites from the other body organs. Of 132 core metabolites, 27 are linked to sleep but only 3 kept the same ‘sleeping pattern’, the other 24 changed to the new 12 hour time zone. Result: Metabolic confusion. The organs most affected were the liver, pancreas and the gut; they were disrupted while there was no change to the master clock.
The net result is some biological signals are saying it is day, while others are saying it is night, and this causes metabolic confusion. And illness.
The research was conducted involving ten men and four women, aged 22 to 34 years, who all stayed one week at a research centre. Half had a night-shift sleep pattern for three days and half had a day-shift pattern. After three days, the volunteers were kept awake for one day in a constant routine with a constant level of temperature and light. They received identical snacks every hour and provided blood samples every three hours.
Chris Woollams, former Oxford University Biochemist commented, “This is an important piece of research and the NIH funded it. We have several other important articles on disrupted sleep on this website, notably the popular “Why can’t I Sleep?”
I’m really not surprised that the body’s metabolism fell into chaos and this is a concern for all night shift workers, from Hospital Staff to Policemen. I think in real life it could be even worse as the researchers commented on loss of melatonin from the pineal gland during sleep. Now we know that approximately 60 times more melatonin is made throughout the body by the Infra Red end of sunlight when you spend time outdoors, even on the darkest days. And these people were all kept in a laboratory. The loss of this hormone through night shift work could be even greater than in this study, and we know it is the number one antioxidant made in the body and a huge anti-inflammatory – it calms and cleans up our cells. We know night shift workers have more breast and prostate cancer because of lowered melatonin production.”
The Research was led by Professor Hans Van Dongen of Washington State.
- Separation of circadian- and behavior-driven metabolite rhythms in humans provides a window on peripheral oscillators and metabolism. Skene DJ, Skornyakov E, Chowdhury NR, Gajula RP, Middleton B, Satterfield BC, Porter KI, Van Dongen HPA, Gaddameedhi S. Proc Natl Acad Sci U S A. 2018 Jul 10. pii: 201801183. doi: 10.1073/pnas.1801183115.