Diabetes, shift work, sleep and appetite

Friday, 19 July 2019

Just like food, water, air and shelter, sleep is an essential requirement for staying alive. For obvious ethical reasons we have little research to confirm how long a human could live without sleep, however it is estimated to be roughly around 10 days.

The term ‘body clock’ is a real thing. We have evolved over time to develop clever internal cues that force us to take a break from the conscious world to essentially reboot our system. It is synchronised to a 24-hour period and is determined by day and night light cycles, work and eating patterns.

The longer you stay awake the bigger your drive is to sleep. Research has shown our ‘circadian rhythms’ make the hours between 4-5am the hardest to stay awake and 6-7pm as the most difficult to go to sleep.

Why do you need sleep?

Not only is it essential for survival, but sleep also promotes energy, can improve your performance of daily tasks, helps boost your immune system and can improve your learning and memory.

How much sleep do you need?

Recent studies have shown that a minimum of seven hours per night are ideal for promoting optimal health. As we are all individuals, so are your requirements of sleep, therefore some people may need slightly more or slightly less.

Note though, there is a difference between what optimal health actually means compared to simply just getting through the next day.

How does shift work impact your health?

Shift work often requires working either long, disrupted or night hours. It usually means your body is left fighting against an internal and natural drive to sleep.

Once this happens it can lead to a range of negative consequences for your body and mind. Not being able to sleep at regular and consistent times can cause you to have a shorter attention span, general irritability, poorer decision making ability and possibly slows your reaction times.

From a nutrition and food perspective these consequences can make it tough to make healthy food choices as you simply are not in the right headspace to think clearly.

Previously it was assumed to be fairly simple. It was thought that these circumstances made people more likely to choose more energy dense / nutrient poor foods, leading to eating more. As a result people had a higher chance of gaining extra weight and being more at risk of chronic conditions like type 2 diabetes.

While this remains partly true, there is now growing evidence to show sleep patterns actually directly impact your hormone levels and metabolism.

Your appetite hormones

When your body is functioning well your hormones help regulate your appetite.

  • Leptin is a hormone that is released from the body to signal to the brain that you are full once you’ve eaten enough food.
  • Ghrelin works in the opposite way and is released in the body signalling to the brain you are hungry and should eat.

A recent small study uncovered that limited sleep each day (ie less than four hours in a 24 hour period) causes leptin to decrease by 18% and ghrelin to increase by 28%.

Other studies show lack of sleep can actually effect key hormones like insulin to not work as efficiently as it should. Long story short, this changes the way your metabolism works and over time can make you at much greater risk of developing type 2 diabetes.

So what next?

Chances are if you work a shift job there’s not much you can do to change the hours of work you do. So the next best thing is to begin making small adjustments in the areas of your life you do have control over. Sleep and eating habits may be something you can tweak.

Practical tips

  • Aim for minimum of seven hours uninterrupted sleep every 24 hours.
  • Aim to eat three main meals and no more than two to three snacks in a 24 hour period.
  • Eat according to the time of the day. For example, if eating in the morning choose something suitable for breakfast.
  • Drink plenty of water across your shift and avoid drinks high in added sugar.
  • Avoid caffeine at least six hours before sleeping.
  • Although alcohol may help you fall asleep initially, it actually disrupts the second half of your sleep.
  • If coming off night shift have a small breakfast before you sleep to stop you waking up due to hunger.
  • If on night shift have a small dinner earlier in the shift and eat small healthy snacks to keep you alert and energised on the remainder on the shift.
  • For ideas on healthy eating and shift work see this handy resource, Shifting Nutrition worksafe.qld.gov.au

There are many barriers you face as a shift worker to prioritise your sleep, nutrition and overall health. If you are struggling to find a routine that works, it may be of benefit to book into see an accredited practising dietitian dietitiansaustralia.org.au. Many people worry that a dietitian is just going to tell you what to eat. However they are highly trained to work together with you and brainstorm ideas and strategies that suit you and your lifestyle. You never know, it might be the biggest investment you ever make in your health.



Linda Uhr, Accredited Practising Dietitian and Diabetes Educator

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