The health effects of night shifts

As society becomes more digitally engaged, there is a growing expectation for 24/7 service across various sectors.

However, working nocturnal hours – although potentially having great financial benefits – could be detrimental in various industries if not policed properly.

Australian Medical Association Western Australia Council of General Practice Member Megge Beacroft, who is also the General Surgery Registrar at the Department of Health, has worked countless night shifts and knows all too well the toll it takes.

“Night shifts are definitely not the same as day shifts,” she said.

“In the health sector, we don’t have the choice to do all of our work in the daytime.

“When you go home and try to sleep during the day, it is physiologically and socially impactful.”

What night shifts are really like

In Dr Beacroft’s experience, preparing for the first night shift is the most difficult part, as the body is trying to sleep during the day when it is not acclimatised to do so.

“If you haven’t managed to get adequate sleep in advance, you may have had less than your required amount of sleep,” she said.

“A study from physicians in the UK showed that if you didn’t get enough sleep before your night shift, it could be the equivalent of performing work with a blood alcohol in excess of 0.05."

“The same level of detail is associated with slower reflexes, slower learning and difficulty accessing short-term memory, which in a very intellectual role like medicine, clinical processing and decision-making, as well as performing procedures, is really important.”

According to the University of Missouri College of Engineering, which assessed the relationship between car accidents and sleeping disorders, shift work sleep disorder increased the risk of a vehicle crash by 300 per cent.

Dr Beacroft said in the medical world, these night shifts were often 12-14 hours long, further adding to the fatigue and stress on the body.

“It also impacts you socially as well,” she said.

“You’re exhausted when you come home from a night shift at 8 am, you don’t have meaningful relationships with the family, and if you have kids, then they’re off to school already.

“Even your partner’s probably gone to work.

“When you get up at night, you’re trying to have lamb chops and salad for breakfast.

“You miss conversations and little jokes with your friends – one thing we’ve learnt from COVID-19 is how important those social interactions and the impacts of social isolation are on your mental health.”

Understanding the why

The body reacts poorly to night shifts due to hormones in the body and the circadian rhythm, which regulates sleep.

Perth Sleep Clinic Founder Michael Prichard, who commenced his career as a consultant in respiratory medicine in 1986 before opening the clinic in 1995, said there were two important and separate processes in the body, which were constantly working – the circadian drive and sleep drive – also known and the C and S processes.

Source: sleepjunkies.com

“Process S is the homeostatic sleep drive, which increases with the duration of wakefulness. The longer we stay awake, the more tired we feel and the more we will need to sleep,” Dr Prichard said.

“Process C is the circadian rhythm under the influence of the internal biological clock, which is a roughly 24-hour cycle linked to the solar cycle.

“This rhythm oscillates between periods of increased sleepiness (early hours of morning and early afternoon) and peak alertness (morning and early evening).

“Bright light exposure prior to the usual bedtime can lead to delayed sleep phase, whereas morning bright light exposure can have the opposite effect.”

The toll night shifts take on the body

“The effect of night shift work on sleep, general wellbeing and long-term health is due to a combination of factors that influence total sleep time and other interactions with general health such as the time, ability or inclination to exercise, as well as appetite, eating behaviours and social contact,” Dr Prichard said, adding that while the body is resilient and has the ability to adapt to changing sleep behaviours, over time, there will be severe consequences.

“Sleep is restorative of brain function, mood and general wellbeing.

“It is sufficiently flexible, so it is possible to change sleep time and duration at will to tolerate short periods of sleep deprivation and still function. 

“Therefore, the flexibility of sleep timing and duration makes it possible to work shifts.

“However, this makes it susceptible to the influence of behaviour, time usage and stressors.”

Dr Prichard said insufficient, disrupted or poor quality of sleep often caused inflammation in the body, which could lead to lowered overall wellbeing – such as low energy, fatigue and difficulty concentrating – as well as a heightened risk of disease.

Several studies have also found links between night shift workers and greater risk of breast cancer, obesity, miscarriage and more.

“The risk of obesity is partly related to the effect of shift work on the circadian rhythm and regulation of hormones that control appetite, as well as the timing of eating,” Dr Prichard said. 

“In addition, there may be an association between the type of work and availability of less healthy food – high carbohydrate and fat content – and in increased quantity.

“Insufficient sleep causes fatigue, which increases appetite for carbohydrates. Weight gain increases the risk of obstructive sleep apnoea, which, in turn, increases the risk of both cardiovascular disease and cancer.”

Dr Prichard said heightened risks of breast and prostate cancer, as well as cardiovascular disease, could be related to the inflammatory effects of insufficient sleep. While fatigue, mild cognitive impairment, disturbances in mood and reduced energy often led to anxiety and depression.

What employers should consider

Dr Beacroft said employers needed to understand the different productivity levels between a day and night shift worker, especially those who shifted between the two, as changing from day to night shifts had an increased strain on physical and mental wellbeing.

“The flicking back and forth is the hardest because you are very fatigued at both ends of your runs,” she said.

“Leading up to your night shift, you’re trying to sleep during the day when you’re not tired, and then coming off your night shifts, you are trying to switch back very quickly.

“That can have a long-term impact on stress hormones, which can lead to mental health concerns.

“It’s really important for employers to not consider a day and a night shift as the same thing. Do not expect a day and a night shift worker to do the same work at the same level of productivity because it’s not the same, especially if they’re flipping back and forth between day and night.”

Dr Beacroft recommended for employers not to have night shift workers complete administration work and tasks, which would be error-prone when fatigued.

“Your motor skills are impacted, short-term memory is less and you’re prone to making mistakes and not realising,” she said.

“Treating workers differently from the day shift is really important.”

Dr Prichard and Dr Beacroft both agreed that employers who allowed naps during night shifts could have incredibly beneficial effects on their ability to perform while also offsetting some of the effects of the circadian rhythm and insufficient sleep.

“Shift design is very important – avoid reverse shift cycles (night-afternoon-day) and ensure adequate breaks between shifts,” Dr Prichard said.

“There’s evidence that napping for around 45 minutes in the middle of a night shift boosts your alertness and can increase the safety of that shift,” Dr Beacroft said.

What night shift employees can do

Dr Prichard outlined some steps for individuals who work night shifts to help maximise their short-term and long-term wellbeing:

• Take a brief nap before the night shift

• Optimise sleep hygiene by implementing positive pre-sleep behaviours and creating a sleeping environment that promotes better sleep quality

• Wear dark glasses on the way home after night shift

• Ensure a quiet dark sleeping environment for daytime sleep after a night shift

• Stimulants such as coffee or caffeinated drinks may work short term, but do not rely on them to remain awake at night or if sleep deprived, as there may be adverse effects

• Sometimes sedatives just prior to bedtime help with a day or night sleep around the time of shift changes, however, this needs to be prescribed and used appropriately.