Abstract

Night shift work is a risk factor for viral infection, suggesting that night shift schedules compromise host defense mechanisms. Prior studies have investigated changes in the temporal profiles of circulating cytokines important for priming and restraining the immune response to infectious challenges from night shift work, but not by way of a 24-h constant routine of continuous wakefulness devoid of behavioral or environmental influences. Hence the true endogenous pattern of cytokines, and the combined effect of sleep loss and circadian misalignment on these cytokines remains unknown. Here, 14 healthy young men and women underwent three days of either a simulated night shift or a simulated day shift schedule under dim light in a controlled in-laboratory environment. This was followed by a 24-h constant routine protocol during which venous blood was collected at 3-h intervals. Those who had been in the night shift schedule showed lower mean circulating TNF-α (t₁₃ = -6.03, p < 0.001), without any significant differences in IL-1β, IL-8 and IL-10, compared with those who had been in the day shift (i.e., control) schedule. Furthermore, circulating IL-6 increased with time awake in both shift work conditions (t₁₃ = 6.03, p < 0.001), such that temporal changes in IL-6 were markedly shifted relative to circadian clock time in the night shift condition. These results indicate that night shift work compromises host defense by creating cytokine conditions that initially impede anti-viral immunity (lower TNF-α) and may eventually promote autoimmunity (mistimed rise in IL-6).

https://www.sciencedirect.com/science/article/pii/S2451994421000043?via%3Dihub

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New research may provide answers as to why some people tolerate being awake at night better than others.

Ida Kvittingen JOURNALIST

PUBLISHED Friday 18. september 2020 – 10:58

Staying awake at night and being able to sleep during the day goes against our natural circadian rhythm, but some people cope better than others.

Recently, researchers have found evidence that biological differences between the sexes can affect the circadian rhythm of both humans and mice.

There are many indications that women and men have internal clocks that are set a little differently, according to a background article in the journal Science about some of the more recent research in the field.

“It’s exciting and quite new that we can say something more about the mechanisms behind the differences in circadian rhythms,” says Andrea Rørvik Marti, a PhD candidate in psychology at the University of Bergen (UiB).

But she’s quick to add that while gender can affect circadian rhythms, a lot of other things may do so too. There are many more similarities than differences between the sexes.

Your biological clock is found throughout the body

Nobel laureates Michael Rosbach, Jeffrey C. Hall and Michael W. Young found that genes control our inner clock, which ticks away depending on light and darkness.

This clock is found throughout the body, Marti says, but the brain is in the driver’s seat.

“The brain is the conductor of an orchestra. Every single cell in our body contains genes that control that clock. They are the musicians,” she says.

“When you have to be awake and active at an unexpected time, you confuse these clocks. The big question is why some people have problems as a result, and why others deal with it quite well,” she says.

While some people think night shifts are fine, other people never get used to them.

Read more at: https://sciencenorway.no/biology-gender-and-society-sleep/do-men-and-women-have-different-circadian-rhythms/1742390

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