Night Shift Sleep Schedule Can Lead to Stroke and Diabetes

Shift workers, or people who work evening and overnight shifts, are at a significantly increased risk for sleep disorders and metabolic syndrome, which increases their risk for heart disease, stroke and type 2 diabetes mellitus. That’s according to a newly published clinical review.

Researchers say night-shift workers are especially prone to developing sleep disorders and metabolic syndrome. The risks increase even more for those who work irregular or rotating shifts.

“The strength of our economy and safety of our society depend heavily on night shift workers,” says Kshma Kulkarni, OMS III at Touro University College of Osteopathic Medicine, and lead study author. “It is critical we address the health issues facing people in this line of work.”

Kulkarni says 17.7% of the U.S. labor force works outside the hours of 6 am and 6 pm. She adds that shift workers are central to the travel, hospitality and ecommerce industries, as well as the 24-hour support needed from nurses, physicians and first-responders, like police and firefighters.

One study found 9% of night-shift nurses developed metabolic syndrome, compared to only 1.8% of day shift nurses. Other studies have noted that risks gradually increase with accumulated years of shift work.

Working nights disrupts individuals’ circadian rhythm, the body’s internal clock responsible for neural and hormonal signaling. Once a person’s circadian rhythm is desynchronized from their sleep/wake cycle, they will likely experience disturbances in hormonal levels, including increased cortisol, ghrelin and insulin and decreased serotonin, among others.

The cascade of hormonal changes is what prompts the development of metabolic disorders and causes people to develop multiple chronic conditions. Kulkarni recommends the following measures to prevent serious health issues associated with shift work.

The first essential step for night shift workers is to establish consistent sleeping hours, says Kulkarni. Employers can help by eliminating rotating shifts that disrupt sleep patterns even further. They can also schedule shifts to start before midnight and last no more than 11 hours to help workers adjust and stabilize their new circadian rhythm.

She adds that workers can maximize their rest by following some basic tips:

  • Sleep in a 7- to 8-hour block every 24 hours, ideally at the same time each day
  • Schedule the main block of sleep as close to evening or night as possible to minimize circadian disruption
  • Take an additional nap for 20 to 120 minutes earlier in the day to prevent fatigue

Exposure to light promotes wakefulness in general, so researchers recommend night shift workers increase their light exposure prior to and throughout their shifts. In addition, employers can install high-intensity lights (~3,000 lux) to simulate daylight exposure and assist circadian adaptation.

Conversely, when coming off shift, workers should minimize their blue light exposure. Blue light is prominent in electronic screens and can delay melatonin production. Research shows avoiding blue light 2 to 3 hours before sleep can improve sleep quality. Kulkarni says workers can stay off their devices and/or wear orange tinted goggles to block out blue light.

“It’s true that getting enough sleep, eating right and exercising are critical to everyone’s health,” says Kulkarni. “However, the nature of shift work is so disorienting and discordant with those principles, we really need to help people in those jobs strategize ways to get what they need.”

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