What are the Health Risks Associated with Shift Work?

Posted by Dr Sophie Bostock - Sleep Expert on 25th May 2023

What are the Health Risks Associated with Shift Work?

One of the major challenges with shift work is that our body clocks can go out of sync with each other, as well as with the light-dark cycle of the sun, which puts the body under strain. This is called Circadian Desynchrony. It puts our entire system under strain and reduces our capacity to recover.

A man asleep at his post in a factory wearing a safety helmet

In the short term, circadian desynchrony can cause the symptoms of jetlag, such as difficulties concentrating, headaches, GI upsets, fatigue and insomnia.

In the longer term, circadian desynchrony means higher risks of chronic illness. For example, if you eat late at night, the body is less efficient at metabolising sugar than it would be earlier in the day, and you’re more likely to store excess energy as fat. Shift workers are at higher risk of weight gain and diabetes.

Night workers also produce less melatonin. This is well known as the hormone that signals sleep, but it also has antioxidant properties which may help to prevent cancer.

Most research studies suggest that night shift workers get between 1 and 2 hours less sleep every day than non-shift workers.

Sleep allows the brain and body to recover and repair itself. Stress hormones and blood pressure dip to their lowest levels during deep sleep, which is also when growth hormone and testosterone are produced.

When sleep is routinely compressed to fewer than 7 hours, research has found that we are more vulnerable to infection, high blood pressure, mental health disorders, and lapses in memory and concentration.

Lack of sleep can also influence our behaviour. When we’re sleep deprived, we’re more impulsive, we’re more likely to crave energy dense foods, and we have less self-control to resist those cravings. We also have less energy for ‘healthy’ choices such as exercise, and cooking healthy foods.

For shift workers who experience a combination of sleep loss AND circadian disruption, this means that they are at increased risk of accidents at work, and while driving home, obesity, weight gain, type 2 diabetes, coronary heart disease, and breast, prostate, and colorectal cancers.

How can you manage the health risks associated with shift work?

There are lots of factors which influence your risk of disease, including your age, your family history, where you live, your lifestyle habits, any existing health conditions, and how much stress you’re under - plus what type of shifts you’ve been working and how long for.

It’s therefore very difficult to isolate how much added risk comes simply from shift work. Studies typically find that the risk of illness is perhaps 5 to 30% higher in shift workers who experience night work.

It is definitely NOT the case that every night shift worker gets ill because of their work, but they are a bit more vulnerable than the general population.

This means it’s all the more important for shift workers to make healthier choices, such as:

Firstly prioritise lifestyle habits which can reduce your risks of ill health. For example:

  • Not smoking
  • Only drinking alcohol in moderation
  • Staying fit and active
  • Eating a Mediterranean style diet, with plenty of fresh fruit and vegetables, and limited processed foods.

Secondly, when it comes to driving and night shifts, be cautious. If you’re struggling to keep your eyes open, at any time, pull over and have a nap. One recent study suggested that night shift workers were 3 times more likely to have a car accident in comparison to day workers. If you can, try to use public transport, or ride sharing schemes.

Thirdly, take advantage of health screening opportunities which are offered to you by your healthcare provider, or employer. For most chronic conditions, if you spot the signs early, you have the best chance of prevention, effective management and treatment.

Finally, if at any time you’re having serious difficulty coping with shift work, speak to your doctor, or healthcare team. The sooner you identify the problem, the sooner you can start to solve it.

What is shift work disorder?

Some people have more trouble adapting to night shifts than others. This might be due to a mismatch between a specific shift pattern and your chronotype, but may also be linked to the amount of stress you’re under.

Shift Work Disorder refers to a difficulty adapting to shift work patterns with disturbed sleep before or after the shift, and/or excessive sleepiness and fatigue during shifts, which persists for at least a month.

According to NICE, the National Institute for Health and Care Excellence, the recommended approach to coping with Shift Work Disorder is:

  • To follow good sleep hygiene advice, such as that described in  our shift work article
  • Track your sleep using a sleep diary to understand what might be causing the issue
  • Take regular breaks and protected naps where possible
  • Get exposure to bright light during the shift and avoid light on the way home after a night shift
  • Avoid driving after a night shift if you feel drowsy
  • Manage any underlying sources of stress
  • Get advice about how to optimise scheduling and the work environment.
  • Seek specialist medical help if symptoms persist.

    Does shift work get harder as you get older?

    Research on the effects of aging on tolerance to shift work is pretty inconclusive.

    Some studies suggest that it takes longer to recover from shifts in our circadian rhythm as we get older, but there is a lot of individual variation.

    Sleep does tend to become more fragmented with age, partly because of a natural decline in melatonin. This might have a bigger impact on night shift workers who already struggle to get enough good quality sleep during the day.

    As we get towards retirement age, our body clocks also tend to shift forwards, to more of an early bird pattern. This could cause more strain for older workers having to work late into the night.

    In contrast, young adults tend to have a delayed body clock, so they are more likely to have problems adapting to early morning shifts.

    Whatever your age, if you’re having difficulty coping with shift work, speak to your manager or a healthcare professional. Lack of sleep and disrupted sleep-wake patterns can put you at increased risks of accidents and illness, so it’s important to be proactive about protecting your safety, health and wellbeing. 

    authors profile
    Dr Sophie Bostock
    Sleep Expert
    Sophie brings a wealth of expertise to the role having spent the last six years researching and championing the importance of sleep science in NHS and corporate settings. Sophie was responsible for improving access to the award-winning digital sleep improvement programme, Sleepio, as an NHS Innovation Accelerator Fellow. She has delivered hundreds of talks, including for TEDx and Talks@Google, and regularly features as a media sleep expert.
    Read more from Dr Sophie Bostock