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How shift work affects your health

A graphic split down the middle with daytime objects and activities on the left and nighttime on the right with a figure of a woman on the left and a man on the right

Around 15-16 per cent of Australian workers report being shift workers. [See Nicole’s story about being a shift-working registered nurse at the end of this blog]

Shift workers can refer to people that work morning shifts, afternoon shifts, evening shifts, split shifts, rotating shifts, or irregular shifts.

In the Queensland community they include health workers, aged care workers, emergency services workers, aviation and transport workers, agricultural workers, hospitality workers, security industry workers, factory workers, mine workers, and others.

Some do it because their job requires it. Some do it for financial benefit. Others find it fits in better with family and other commitments.

Whatever the reason, there are real health consequences from doing shift work that you should know about.

The internal clock

Humans have a remarkable internal clock called the suprachiasmatic nucleus (SCN) located in the hypothalamus in the brain. Sunlight sets your internal clock, but it works even when there is no day and night. Research has shown that even if you are in a cave or kept in a room with no light, your internal clock can keep your body’s 24-hour cycles going for some time. This varies only slightly between people – between 23.5 and 24.6 hours. This may be why some people are night owls and others are early birds.

A Queensland Health registered nurse in front of the large digital screens of the patient access coordination hub (PACH) at the Princess Alexandra Hospital

Biological cycles

Many of the health problems that can arise from shift work are because it disrupts these ancient cycles.

There are a range of biological cycles: diurnal (night and day), circadian (24 hours), ultradian (less than 24 hours), infradian/circalunar (1 month), circannual (1 year), and others.

The major rhythms affected by shift work are the circadian and diurnal rhythms. They are regulated by cells in the brain that receive signals from the eyes about light and dark.

These two rhythms affect many processes in the body, including the sleep and wakefulness cycle, hormone levels, metabolism, heart rate, blood pressure, blood sugar and cholesterol levels, body temperature, digestion, urine production, mental health risk factors, the immune system, DNA repair processes, and more.

Night shifts are the most disruptive, as they mean people need to sleep in daylight hours. People who work night shift tend to get less sleep than others. Research also indicates that sleeping in daylight hours is less beneficial, even if you get the same amount.

If you’ve ever been jetlagged, you’ve felt what happens to your body and mind when your cycles get even slightly out of whack. Typical symptoms of jet lag can include an inability to focus, intense sleepiness, being unable to sleep, fatigue, digestive system upsets, and general crankiness, and that is after a relatively short one-off disruption.

Related issues

It’s not just the disrupted cycles and sleep loss, though. Shift work can cut people off from social events and friends and family, leading to feelings of isolation.

It can be harder for shift workers to eat healthily and get enough regular exercise, too.

Health risks

There is good evidence that shift work is related to serious health issues, such as increased obesity, diabetes, cardiovascular disease, cancer, stomach and digestive disorders, ulcers, fertility issues, depression, higher risk of family and social problems, and an increased risk of workplace or motor vehicle accidents.

A senior indigenous midwife and trainee health practitioner from the Boomagam Caring Indigenous Maternity Team, Darling Downs Hospital and Health Service smile at the camera outdoors

What to do as a shift worker

Getting enough quality sleep is of major importance. Practicing good sleep hygiene can go a long way towards helping you do this. Even minor exposure to bright sunlight can make it hard to sleep. Your room should be as dark as possible, or you can try using a sleep mask. Avoid using devices with a screen in the hour before sleep. If you work night shift, it may be helpful to travel home in the morning with sunglasses on to reduce your exposure to bright daylight.

Some employers are changing the ways shifts are structured and rostered and are providing facilities for employees to nap at break times to minimise the health effects and improve workplace safety. Talk to your employer. Sleep experts say if you’re napping during work time it’s best to keep them to less than 30 minutes, so you don’t fall into a deep sleep. This will prevent you from feeling very sleepy when you wake up, and you can get back to work right away.

Try to eat well and get regular exercise. This can be challenging, but it’s not impossible. Taking your own meals to work can help you eat less canteen food or take away. If you use public transport you could try getting off the bus or train early and walking the last bit to work or home or find a nearby gym that is open 24 hours.

Get a regular health check and let your GP know you are a shift worker. They can keep an eye on your health and, if necessary, test you for risk factors such as raised blood sugar levels.

A clock on a bedside table in a darkened room showing 7:30 with a hand reaching for a sleeping mask on the bed

Nicole's shift-work story

Nicole is a social media officer and married mum of two. Prior to working in social media, she was a registered nurse for 22 years, working in hospitals and other healthcare settings involving shift work.

‘When you work night shifts there’s an isolation and a social disconnect. You miss out on social events with friends and family and socializing with work colleagues. During night shift people are sleeping so you need to be quiet, making it hard to have a good chat with colleagues. You also miss out on meetings and learning opportunities at work that happen during the day.

‘I found it so hard to sleep during the day, even though I tried all the recommendations, such as a dark room, quiet, and so on. I still couldn’t sleep properly. I would usually average about 4 hours sleep during the day after a night shift, then would have a nap for about an hour before I went back to work that night. There’s a cumulative effect. You might work three or four shifts in a row, you’re so tired, you get a few days off, but you can’t sleep properly because you are busy and overtired, next thing you’re back at work still tired, to do a bunch more shifts.

‘Working different shifts worked well when I was younger without a family because of the flexibility. I could sleep in some mornings, finish early after a morning shift and go do fun things, visit a friend, get things done in the afternoon. Before an evening shift I could go shopping or exercise or something, so that flexibility was good.

‘But working rotating shifts was very different with kids, because the shifts often didn’t fit with the family routines, and that caused additional stress and affected the family dynamics. Working only night shifts was better for the routine and the finances, but worse for my physical and mental health, because I was always tired.

‘I was lucky that my husband was really supportive, but he had a full-time job as well, and couldn’t always help me with the kids. We moved to Queensland not knowing anyone so had no family or other support to begin with. Eventually we made friends who were more than willing to pitch in and help out where they could.

‘I think the shift work did make things very difficult and tense at times and put pressure on the relationship. But communication was always the key, talking about how I felt. Because he was not a shift worker, it may have been difficult for him to relate to how I was feeling. But talking about it helped us to work out how we could work together, so that things were as normal as possible under the circumstances in the family.

‘Don’t be afraid to ask for help, because people will help if you ask them, like with the kids, or going to get groceries for you if you’re really tired.

‘Don’t panic about not being able to sleep, just rest as much as you can even if you can’t get into a deep sleep. I used to just lie there with my eyes closed, but at least it’s still resting your brain and body, and sometimes I’d drift off to sleep.

‘It’s really important to cut yourself some slack, don’t put pressure on yourself, or beat yourself up because you’re finding it hard to cope, just realise that you’re doing your best. If you’re struggling with your shifts, talk to your manager and see what you can work out. Most of the time they’re pretty understanding. Often, they will have worked shifts themselves. Talk to your partner, your family and your friends about how they can help. If you’re really struggling it’d be worth talking to a professional.’

More information

Last updated: 10 June 2022