Beware: Night shifts can increase your risk of heart disease, diabetes

Researchers say that shift workers are at a significantly increased risk for sleep disorders and metabolic syndrome, which increases a person's risk for heart disease, stroke and type 2 diabetes.

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, said a new study, published in The Journal of the American Osteopathic Association. "The strength of our economy and safety of our society depend heavily on night shift workers, it is critical we address the health issues facing people in this line of work," said Indian-origin researcher and study lead author Kshma Kulkarni from Touro University in the US.

One study found nine per cent of night-shift nurses developed metabolic syndrome, compared to only 1.8 per cent of day shift nurses. Other studies have noted that risks gradually increase with accumulated years of shift work. According to the researchers, 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 study added.

The cascade of hormonal changes is what prompts the development of metabolic disorders and causes people to develop multiple chronic conditions. Sleep in a 7- to 8-hour block every 24 hours, ideally at the same time each day and schedule the main block of sleep as close to evening or night as possible to minimize circadian disruption, the researchers recommended. Take an additional nap for 20 to 120 minutes earlier in the day to prevent fatigue, they added. Exposure to light promotes wakefulness in general, so researchers recommend night shift workers increase their light exposure prior to and throughout their shifts.

Prior studies have shown shift workers are more likely to eat snacks higher in sugar and saturated fat while consuming less protein and vegetables, and more likely to skip meals. "It's true that getting enough sleep, eating right and exercising are critical to everyone's health," Kulkarni said. "However, the nature of shift work is so disorienting and discordant with those principles, we really need to help people in those jobs strategise ways to get what they need," Kulkarni added.