Study: The Health Effects of Overnight Shift Work

By: Roz Brown, Public News Service – NM

ALBUQUERQUE, N.M. – A new study confirms it doesn’t take long for altered sleep patterns to affect a person’s health. While people who work night shifts make up about 20 percent of the global workforce, a University of Colorado study asked a group of men to live like they worked the night shift for just a few days.

Lead study author Christopher Depner says pulling an all-nighter even once can disrupt more than 100 critical proteins in the blood, including those that influence blood sugar, energy metabolism and immune function.

“For the proteins related to energy expenditure, some of those proteins were changing in a way where participants were actually using less energy across the day, which could actually lead to weight gain and obesity over time,” he explains.

Researchers recruited six healthy, male subjects in their 20s for the study, to spend six days in the sleep lab, where their meals, sleep, activity and light exposure were tightly controlled, and their blood was checked every four hours for protein levels.

Depner believes the findings could lead to new treatments for night-shift workers, who are at higher risk for diabetes and cancer.

He notes the study is the first to examine how protein levels in human blood vary over a 24-hour period and how sleep and meal timing impacts them.

“We simulated shift work, but it applies for sure to jet lag and, yeah, college students pulling an all-nighter for studying, or even if you just really change your sleep-wake schedule over the weekend,” he adds.

Depner believes the study results also could enable doctors to someday time when people are given medications, vaccines and diagnostic tests around the circadian clock.

“As we start to identify how these proteins cycle across the day, we can identify the best time of day to administer some drugs,” he notes. “And this could help us potentially reduce the dose that we need for the drugs, minimize side effects and things like that.”

Other studies have confirmed that long-term night-shift work can contribute to certain cancers, heart disease and ulcers, among other health issues.