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Researchers at the University of Colorado at Boulder have found that night shift work, and even jetlag, may affect the body’s physiological alignment via blood proteins that are involved in energy metabolism, blood sugar levels and immune function. 

The study, a first-of-its-kind, analyzed protein levels in human blood by recruiting six male subjects and controlling their meals, sleep, activity and light exposure. 

Over a period of six days, the researchers observed how changing sleep patterns and meal timing had an impact on protein levels in a person’s blood. 

For the first two days of the study, the sleep-wake schedule was consistent with the subjects’ normal everyday schedule of sleeping at night and being awake through the day. On the third day, the six men were gradually transitioned to a pattern of sleeping for eight hours during the day and being awake all night, including eating, which is consistent with typical night shift work. 

After drawing blood every four hours to examine the activity of 1,129 proteins, the researchers found that the patterns of 129 proteins in the blood were misaligned after just one night of the simulated night shift. 

“By the second day of misalignment, we were already starting to see proteins that normally peak during the day peaking at night and vice versa,” Chris Depner, lead author of the study and postdoctoral researcher in the Department of Integrative Physiology, said.

Glucagon, a protein that causes sugar to be pushed into the bloodstream, showed to be one of the proteins in misalignment after the subjects followed the first night of night shift work. This protein acts as a stimulus and prompts the liver to push the sugar, which may explain the higher risk for diabetes and the higher proportion of diabetes rates in night shift workers. 

Researchers also found that while following the night shift work schedule, subjects’ levels of fibroblast growth factor 19, a protein found to burn calories in animal models, fell short when misaligned as subjects burned 10 percent fewer calories.

Furthermore, the study determined that these proteins may vary in how they are impacted based on a person’s internal circadian clock. Not only are blood protein levels influenced by sleep and meal timing, they are significantly altered by internal circadian time alone.    

These findings, published in the journal PNAS, may help bring about future treatments for night shift workers who suffer from higher risks of diabetes and cancer.

“This tells us that when we experience things like jet lag or a couple of nights of shift work, we very rapidly alter our normal physiology in a way that, if sustained, can be detrimental to our health,” Kenneth Wright, senior author and director of the Sleep and Chronobiology Laboratory and professor in the Department of Integrative Physiology, said. 

This new research could enable the practice of timed-administration of drugs and tests that are focused around precision and the internal circadian clock of each individual. 

“If we know the proteins that the clock regulates, we can adjust timing of treatments to be in line with those proteins,” Depner said. 

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