For many years, health experts have warned those shift workers who work graveyard or rotating shifts about the cardiovascular health problems, including obesity and heart attacks, that come with it. Now, a study published in Endocrinology claims that shift work may also lead to severe ischemic stroke.

David Earnest, a professor in the Department of Neuroscience and Experimental Therapeutics at the Texas A&M Health Science Center College of Medicine, explains that the work’s longer hours or unusual hours should not be blamed. In reality, it is the disruption in the body’s circadian rhythm that prevents it from doing its normal process during a 24-hour period.

“The body is synchronized to night and day by circadian rhythms–24-hour cycles controlled by internal biological clocks that tell our bodies when to sleep, when to eat and when to perform numerous physiological processes,” says Earnest. “A person on a shift work schedule, especially on rotating shifts, challenges, or confuses, their internal body clocks by having irregular sleep-wake patterns or meal times.”

graveyard shift

Nurse working during his night shift. Credit: University of Virginia

The researchers tested animal subjects for this study. They found that those animals on a person’s shift work schedules were more likely to experience brain damage, loss of sensation, and immobility stemming from a severe stroke.

Males and females experienced different severity. Males were more likely than females to suffer from the severe stroke outcomes.

Farida Sohrabji, who is also a professor in the Department of Neuroscience and Experimental Therapeutics as well as the director of the Women’s Health in Neuroscience Programme, explains that this gender difference may be associated with reproductive hormones. The estrogen is believed to provide protection to the brain from stroke. The professor asserts that menopausal women are more prone to ischemic stroke and poor recovery due to the decreased production of the female sex hormone.

Moreover, the same health consequences from unusual work schedules can also be experienced by others with social jet lag. The findings suggest close monitoring of shift workers. The team says maintaining one’s regular mealtimes could help prevent the health problems of irregular sleeping patterns.