Night Shift Work Is Quietly Destroying Millions of Workers' Health

The Invisible Workforce Paying a Heavy Price

While most of us sleep, more than 8.7 million people in the UK keep hospitals running, stock grocery shelves, patrol the streets, and ensure the wheels of modern life never stop turning — a "hidden army" of night shift workers who are essential but often invisible. And the cost of that service, it turns out, is far steeper than most people realize.

For the more than three million people in the UK working night shifts, who have little choice but to disrupt their sleep, the health consequences are mounting. Sleep deprivation alone costs the UK economy a staggering £50 billion per year in lost productivity, worker attrition, and accidents, with night workers making up a significant share of that figure.

A Body Clock That Cannot Be Overridden

Sleep isn't just about recharging energy — it's a biological necessity that supports cognitive function, emotional regulation, and cellular repair. Humans are hardwired to sleep during the night and be awake during the day, following an internal body clock known as the circadian rhythm. Night shift workers are essentially asking their bodies to do the impossible: function normally while running on the wrong schedule.

Studies of shift workers show that they are at a much higher risk of type II diabetes, gastrointestinal disorders, cancers, heart and stroke problems, obesity, depression, and memory loss than employees who work regular 9–5 roles. The risks don't stop there. The World Health Organization's International Agency for Research on Cancer has classified night shift work as "probably carcinogenic to humans," placing it in the same risk group as red meat, citing evidence for links to breast, prostate, colon, and colorectal cancers. This may be because disruption to the body's circadian system alters the timing of melatonin production — a hormone thought to have tumour-suppressing properties — as well as reducing vitamin D from lack of daylight and promoting chronic low-level inflammation.

The effects don't stop at the workplace door. The Health and Safety Executive warns that night work can increase safety risks, including on the drive home after work, when tiredness can undercut reaction time and attention. A poor roster can affect not just one shift but the next day's commute, family life, and recovery sleep.

Could Splitting Sleep Be the Answer?

Shift work is associated with disrupted sleep, circadian misalignment, and increased risks of adverse health, performance, and safety outcomes. Although recommendations for shift workers typically focus on obtaining one long sleep period, many shift workers divide sleep into two episodes — referred to as biphasic sleep. Researchers are now asking whether that instinct to split sleep might actually be the smarter strategy.

Laboratory work by American psychiatrist Thomas Wehr found that when volunteers were given 14 hours of darkness approximating a pre-industrial winter night, they drifted naturally into sleeping in two halves within weeks. "The default," says neuroscientist Russell Foster, "is almost certainly not a single block." Several studies show that napping during shift work, where possible, is associated with reduced sleepiness and improved alertness. Studies of healthcare workers suggest that even a 20-to-50-minute nap during or after a shift improves focus and reduces drowsy driving on the way home.

What Needs to Change

Night shift workers are 75% more likely than day workers to say they often feel left out at work, and 48% more likely to say their managers think their work is easier than it is. That perception gap matters. Addressing the health crisis among night workers requires more than individual coping strategies — it demands systemic change from employers and policymakers alike.

The eventual aim of researcher Line Victoria Moen's work is to develop clear clinical guidelines that might help shift workers and others with disrupted sleep patterns. Shift work is an important, modifiable risk factor for circadian rhythm disturbances and chronic diseases. Study findings justify reducing exposure to night shifts, optimizing work schedules, and implementing preventive programs to improve sleep, lifestyle, and early detection of cardiometabolic complications. The millions keeping society running through the night deserve no less.