In some respects, we’re simple creatures: when it’s light, we’re awake and when it’s dark, we go to sleep. Our physiology is finely tuned to this circadian rhythm, so it’s no surprise that going against your body clock usually doesn’t end well. Which isn’t good news for the countless healthcare workers who routinely work nightshifts. Indeed, findings have recently been published connecting shift workers with an increased risk of type 2 diabetes and cardiovascular disease1.

Circadian Misalignment

But is it inevitable to succumb to ill-health? Well, there are 3 unavoidable changes directly associated with the circadian misalignment of being awake at night and asleep in the daytime.

  • Even though you’re not diabetic, you’ll demonstrate increased insulin resistance. Insulin sensitivity and glucose tolerance is decreased and blood glucose levels will be similar to those in prediabetes2.
  • Your metabolic pathway is disturbed, so energy expenditure is decreased. In other words, the calories you eat during the night count for more than they would during the day and that doesn’t take long to add up to unwanted weight-gain3.
  • Another factor is reduced leptin levels – this is the hormone that tells you that you’re full, so less of it means you get the urge to eat and again, could lead you on the path to obesity3.

Sleep Deficit

The problem is made worse by what happens once your shift has finished and you go home. You should have a light breakfast – maybe cereal or toast – and then 7 -8 hours of sleep. That’s if you can persuade your body clock that sleeping during daylight hours is a good idea2 – not an easy task, you might agree – AND many workers have children to get ready for school, then maybe the shopping or some housework …

Before you know it, you’ve only managed to grab a 3-hour nap and then it’s back to work.

The resulting sleep deprivation brings its own issues. Not only is it also linked with low leptin levels, but also raised ghrelin levels4,5. This is the ‘hunger hormone’ and that’s responsible for the midnight cravings. Having a sleep deficit by itself can also cause reduced glucose tolerance and insulin sensitivity, so being sleep deprived due to circadian misalignment is a double whammy for diabetes risks4.

The resulting fatigue only makes the problem worse. You drink coffee to stay awake but too much of that makes your next sleep less restorative; you have zero interest in doing any exercise and your desire for carb-heavy, sweet and processed food is overwhelming3,4. You need the energy, the sugar rush and let’s face it: you deserve a treat. Sound familiar?

Strategies for Staying Healthy

Enough of the negatives though. Nightshift is often part and parcel of healthcare so how can you do your job AND stay healthy?

OK, so we can’t do anything about the circadian misalignment but it is recommended that you work a maximum of 4 nights then have a recovery night off and as long-term shift work (10-20 years) correlates with an increased risk (40 – 60%) of diabetes, obesity and cardiovascular disease, it might be worth considering a change, if possible4.

Where you can make a real difference though, is with your lifestyle choices.

5 Top Tips for Nightshifts

  1. Bring your own food in and don’t rely on the vending machines. This is crucial – there are usually no good choices in the machine anyway and you will pick unwisely because of your rampaging hunger hormones and flagging energy6.
  2. Prepare light meals such as vegetable soups, salads or wholegrain sandwiches and have dried fruit and nuts on standby for snacks. Try to avoid eating these in the middle of the shift but rather, at the beginning and the end.
  3. If you get bored during the night – be mindful and don’t automatically turn to food as a way of ‘killing time’. Remember, your body simply isn’t designed to eat during the night, so plan ahead and have a strategy of how to entertain yourself.
  4. If you drink coffee, have your last one 4-6 hours before your scheduled sleep, which brings me to…
  5. Prioritise sleep. This is important. You don’t normally get up at 3 AM to do the ironing, so don’t do it during your day sleep. You can’t achieve everything by yourself, so call on people and delegate tasks. You need your sleep just like everyone else.

Nightshifts can be a positive part of your work, as you often spend more time with those patients who are awake and develop further insight into their needs, but to benefit from this, you first have to look after yourself. And as everyone who has ever worked a nightshift knows –  following this advice is definitely not easy; but it is worth it.


  1. Stephenson, J. (2019) How shift work can increase diabetes and heart disease risk. Nursing Times [online] Available from: https://www.nursingtimes.net//news/workforce?blocktitle=Workforce&contentID=27723
  2. Morris, C.J., Purvis, T.E., Mistretta, J. & Scheer, F.A.J.L. (2016) Effects of the internal circadian system and circadian misalignment on glucose tolerance in chronic shift workers J Clin Endocrinol Metab. 101(3); 1066-1074
  3. McHill, A.W., Melanson, E., Higgins, J., Connick, E., Moehlman, T.M., Stothard, E.R. & Wright Jr, K.P. (2014) Impact of circadian misalignment on energy metabolism during simulated nightshift work. Proceedings of The National Academy of Sciences Of The United States Of America,111(48), 17302–17307.
  4. Borba Brum, M. C., Dantas Filho, F. F., Schnorr, C. C., Bottega, G. B., & Rodrigues, T. C. (2015). Shift work and its association with metabolic disorders. Diabetology & Metabolic Syndrome, 7(1), 1–7.
  5. Scheer, F.A.J.L., Hilton, M., Mantzoros, C.S. & Shea, S.A. (2009) Adverse metabolic and cardiovascular consequences of circadian misalignment. Proceedings of The National Academy of Sciences Of The United States Of America, 106(11); 4453-4458.
  6. Souza, R.V., Sarmento, R.A., de Almeida, J.C. & Canuto, R. (2019) The effect of shift work on eating habits: a systematic review. Scandinavian Journal Of Work, Environment & Health. 2019;45(1):7-21.

To discover Relias’ online training for nursing professionals talk to our solutions experts.

Victoria Hancox, B.Sc. RGN RM PGCE M.Sc

Content Writer

Following a decade of experience in the NHS as both a registered nurse working in the operating theatre department, and as a midwife, Vicky became a secondary school science teacher. She worked mainly in International Schools, putting a Clinical Biochemistry degree and a Masters in Science Communication to good use. Although if you ask, who does she prefer working with – teenagers or unconscious patients? – the jury’s still out on that one! In the perfect marriage of bringing healthcare and education together, she now works as a Content Writer with Relias Learning. When she’s not huddled over a keyboard, you can usually find this lifelong vegetarian in the kitchen, where her motto is “When in doubt, throw in some garlic!” Even with cheesecake …

CONNECT WITH US

to find out more about our training and resources