For junior doctors who have to work irregular hours, getting enough sleep can be challenging. A recent GMC survey revealed that more than half of doctors in training worked beyond their rostered hours and 22% said that working patterns left them short of sleep on a daily or weekly basis.

Rotating night shifts are known to disrupt the body's natural circadian rhythm of wake and sleep which is affected by environmental light.

'We have not evolved to be awake at 1am and asleep in broad daylight,' says Dr Michael Farquhar, a consultant in sleep medicine at Evelina London Children's Hospital, who alongside his paediatric clinical work educates other health professionals on the importance of sleep.

'This makes it harder to get the right duration of good quality sleep after a shift and means everything is stacked against you when trying to get back to a normal pattern. It's the same sense of dislocation you have from jet-lag. Imagine trying to function in a high-pressure hospital environment after stepping off a flight from Sydney.'

Michael warns that fatigue is a risk to patient safety.

'It's important to look at what happens when we are sleep-deprived. The first thing we lose is insight, which is dangerous because the brain convinces itself that everything is absolutely fine and we are more likely to persevere when doing the wrong thing. Our sense of empathy is more likely to fade at 3am when we are tired, under pressure and much more likely to lose our temper with colleagues and patients.

'Clinicians are more likely to make errors in simple repetitive tasks, such as calculating medication. In my own specialty of paediatrics, for example, a patient in intensive care might weigh less than a bag of sugar – getting a decimal point in the wrong place could mean the difference between the patient's survival and death. And our ability to process, retain and analyse information suffers too, which means it takes longer to assess a patient's symptoms and reach a diagnosis.'

While NHS hospitals' dependence on junior doctors providing a 24-hour service makes night shifts a necessary evil, Michael wants newly-qualified medics to be better informed and equipped to minimise the impact on their sleep.

'Doctors should know how much sleep they need to function and have a personal responsibility to be properly rested when they arrive for a night shift. You wouldn't turn up to work after a pint of beer, but people's performance can be as impaired by fatigue as it is by alcohol. In fact, working an 18-hour shift without a break can have the same effect on reaction times as being at the legal drink-drive limit.

'There is a myth that 'heroes' need less sleep than ordinary people, but we need to acknowledge that the staff who hold the NHS together aren't superhuman. In a high pressure environment where you can change lives in a heartbeat, we owe it to ourselves and our patients to take sleep seriously.'