The link between shift work and health

Learn the impact that shift work can have on our health and ways you can make improvements.
Published 28 June 2021 | Updated 2 May 2024

Shift work can increase the risk of chronic disease

Shift work has been linked to a greater risk of developing chronic diseases such as cardiovascular disease, type 2 diabetes, certain cancers, gastrointestinal and sleep disorders. There are several behaviours common among shift workers which increase the risk of developing chronic diseases, including:

  • Smoking
  • Excessive alcohol consumption
  • Excessive fat and sugar consumption
  • Lack of physical activity
  • Lack of sleep

Additionally, being overweight further increases this risk. Studies have found that the longer an individual part-takes in shift work, the more likely they are to become overweight.

Shift work can disrupt our circadian rhythm

Circadian rhythm is our internal 24-hour body clock, which controls our natural sleep and wake cycles. Shift workers often have a frequently changing sleep schedule and sleep at different times of the day, compared to regular nine-to-five workers. When our sleep and wake cycles and our eating schedules are different to normal, this can have poor effects on our health. For example, it may increase blood pressure which is a risk factor for cardiovascular disease and our blood sugar levels which is a risk factor for type 2 diabetes. It may also have an impact on our appetite hormones, meaning that we may feel hungrier and less satisfied after a meal, causing us to eat more than we may need and possibly resulting in weight gain.

Why we may gain weight when shift working

> Poorer food choices

Have you found yourself reaching for snacks throughout a shift? Chances are you’re opting for sweet, salty or crunchy foods. Why? We tend to see these foods as the easier, convenient and often cheaper alternative to a nutritious meal. Or perhaps you’ve finished a long shift and found yourself to be too exhausted or time poor to prepare a proper meal. Often in situations like this we reach for the ‘easy’ alternative. Whether it’s fast-food, takeaway or snacking, it’s likely these choices are higher in energy (kilojoules), fat and sugar, all of which when consumed often can result in weight gain.

> Lack of sleep

Not getting enough sleep is common among shift workers. When we are sleep deprived, we often feel hungrier than usual, which may cause us to overeat. Additionally, research has shown that we are more likely to choose high fat foods when we are tired. Both of these factors can increase the risk of weight gain.

> Reduction in physical activity

We know that being active is important for our health and wellbeing, and in turn can help us manage our weight. However when working around the clock, it can be tricky to find the balance and be able to routinely work physical activity into the day. Also, at the end of a long shift, we may feel too exhausted or tired to prioritise activity in our routines.

> Changes to our appetite

A number of factors can contribute to changes in our appetite. For shift workers, a constantly changing sleep and eating schedule can cause changes in the hormones that control our appetite. This means that we may feel hungrier than usual, and less satisfied after a meal, causing us to eat more than we may need and resulting in possible weight gain.