The science behind sleep for shift workers in winter

THE SCIENCE BEHIND SLEEP FOR SHIFT WORKERS IN WINTER

As the clocks go back and the darker days of winter draw in, many of us look forward to an extra hour in bed and cosy evenings indoors. But for millions of people across the UK who work through the night, this time of year brings added challenges. Longer nights, colder temperatures and reduced exposure to daylight can all make it harder for shift workers to get the rest they need – and the consequences for health and wellbeing can be profound.

Today, more than 8.7 million people in the UK work at night – a staggering 27% of the entire workforce. From nurses, drivers and hospitality staff to warehouse operatives and emergency responders, these workers keep society running while the rest of the country sleeps. Yet despite their crucial role, shift and night workers are often described as “the forgotten shift.” Supporting them, especially through the winter months, is vital for maintaining a healthy, engaged and productive workforce.

Why winter makes sleep harder for shift workers

Human beings are hardwired to be awake during the day and asleep at night. This daily pattern is governed by the circadian rhythm – an internal biological clock that synchronises with daylight and darkness. When we’re exposed to light, the brain suppresses melatonin (the hormone that induces sleep) and promotes alertness. When it gets dark, melatonin levels rise, signalling that it’s time to rest.

For night workers, this rhythm is turned upside down. They must stay alert when their bodies are naturally programmed to sleep, and try to rest during daylight hours when their biological systems are telling them to stay awake. The return to standard time in autumn, which shortens daylight hours even further, can deepen this misalignment. Less natural light during waking hours can reduce mood-regulating serotonin levels and make it harder to stay alert at night — compounding fatigue and low mood.

Even if a night worker manages to get eight hours of sleep during the day, research shows that the quality of that sleep is usually lower. Circadian misalignment affects nearly every system in the body: hormone production, metabolism, immune function and emotional regulation all take a hit. Over time, this disruption increases the risk of serious health problems.

The hidden health costs of working nights

The effects of night shift work on health are wide-ranging. Chronic sleep loss and irregular schedules are linked to higher rates of cardiovascular disease, diabetes and sleep disorders:

Cardiovascular disease
Studies show that night shift workers are 37% more likely to suffer a heart attack than their daytime counterparts. The reasons are multifaceted: disrupted sleep, elevated stress, irregular eating patterns and reduced opportunities for exercise all contribute to higher blood pressure and cholesterol levels. Without enough restorative sleep, the body’s ability to repair and regulate the cardiovascular system declines, increasing long-term risk.

Type 2 diabetes
Circadian disruption also plays havoc with metabolism. Night workers are 44% more likely to develop type 2 diabetes, largely due to impaired insulin sensitivity and disrupted glucose regulation. Irregular eating patterns – such as late-night snacking and sugary “pick-me-ups” – only make matters worse. Over time, this combination can push the body into insulin resistance, a key driver of major metabolic abnormalities such as type 2 diabetes and obesity.

Sleep and circadian rhythm disorders
Perhaps unsurprisingly, night shift workers are at far greater risk of developing chronic sleep disorders. Conditions like Sleep and Circadian Rhythm Disorder (SCRD) cause insomnia, excessive daytime sleepiness and fatigue that can impair performance and increase accident risk. These sleep problems often spill over into mental health, leading to anxiety, depression and mood swings.

The mental and social toll

The impact of shift work isn’t confined to the body. Sleep deprivation has a direct effect on mood, memory and emotional regulation. Many night workers report feelings of irritability, depression and cognitive fog. The social effects can be equally damaging: working while family and friends are asleep can lead to isolation, missed social connections and strained relationships. Alarmingly, studies suggest that night shift workers are six times more likely to get divorced than those working regular hours.

The myth of “getting used to” night work

There’s a widespread belief – particularly among managers who have never worked nights – that the body eventually “gets used to it.” The science says otherwise. Academic research has shown that 97% of night shift workers do not adjust to a nocturnal schedule; their bodies remain synchronised to daytime rhythms. Yet polling by Night Club found that only 24% of UK adults recognise that it’s impossible to truly adapt to working nights, and understanding is even lower among night workers themselves (just 16%).

This lack of awareness can breed complacency and even stigma. In many industries, especially male-dominated ones, needing sleep is viewed as a weakness. Polling shows that 56% of workers believe they can still perform well despite poor sleep – rising to 62% among night workers. In reality, research shows that even one or two nights of reduced sleep impair decision-making, slow reaction times and increase risk-taking – a dangerous combination for those operating heavy machinery or providing frontline care.

When sleep is seen as a luxury

For many night workers, sleep simply doesn’t come first. Night Club’s polling shows that 52% of night workers have caring responsibilities (similar to daytime workers) and a third hold second jobs. After a night shift, caring for children or elderly relatives often takes priority over getting proper rest. But the science is clear: sleep is not optional. It is a biological necessity that underpins every aspect of health – from immunity and metabolism to mental wellbeing. Furthermore, the correlations between night shift work and cancer are now considered so strong that shift work is officially classified as “probably carcinogenic” by The World Health Organisation.

Supporting the forgotten shift

As the long winter nights set in, it’s more important than ever for employers and colleagues to recognise the strain that night work places on the body and mind. Encouraging regular sleep routines, providing access to health education, offering warm, well-lit environments and scheduling shifts thoughtfully can make a real difference.

For shift workers themselves, prioritising sleep, seeking daylight exposure where possible, and maintaining healthy routines can help protect against some of the seasonal and long-term effects. Because in the end, sleep isn’t just a comfort – it’s a cornerstone of health that no one, not even the hardest-working night shift, can afford to go without.