Diet, alertness and shift work

Research shows that how you cope with shift work may depend on your health, fitness, age and lifestyle–some people adapt well, others do not.

Getting regular exercise and eating a well-balanced diet can help to help your body to adapt. However for those on the night shift it can be challenging trying to make healthy choices and very tempting to rely on an artificial 'fix'.

Shift workers often turn to stimulants such as coffee, energy drinks or cigarettes to help them stay awake and sedatives such as alcohol, sleeping pills and other non-prescription substances to help them sleep.

Ongoing use or overuse of some stimulants and sedatives can create dependence, which can lead to a need to use higher doses for the same effect, as well as difficulties with withdrawal.

Caffeine in its various forms is the most commonly used stimulant. Caffeine is a mild stimulant present in coffee, tea and cola as well as in tablet form and in 'energy' drinks. The table below shows the caffeine content in a variety of drinks and typical coffee intake.

Drink/productSize/amountCaffeine content
Breaka Strong®600 ml197 mg
Mother energy drink500 ml can160 mg
Red Bull250 ml can80 mg
McDonalds®1 espresso70 (54-83)+*
Instant coffee250 ml cup60 (12-169)*
V energy drink250 ml can50 mg
Diet cola soft drink375 ml can48 mg
Cola soft drink375 ml can40–50 mg
Tea250 ml cup27 (9-51)*

Information in the table is from the Sports Dieticians Australia Fact Sheet on Caffeine, and the Australian Drug Foundation Fact Sheet on Energy Drinks.

*The caffeine content of hot tea, coffee and iced coffee varies widely, depending on the brand, the way that the individual makes their beverage, and the size of their mug or cup.

+Excludes McCafe outlets

Short-term effects of caffeine intake

The short-term effects of caffeine intake can be both positive and negative. Effects include:

  • feeling more alert and active
  • need to urinate more frequently
  • rise in body temperature
  • increased heart rate
  • stimulation of the brain and nervous system.

What happens with higher doses of caffeine?

Caffeine overdose can result in serious injury or even death. The Australian Medical Journal has reported an increase in energy drink related reports to the Poisons Information Service in NSW, and they believe that this increase may be reflected in national statistics. (1)

Some of the adverse health effects associated with excessive energy drink consumption are:

  • insomnia
  • nervousness
  • headaches
  • nausea
  • vomiting
  • rapid heart rate
  • heart-palpitations.

Recommendations for stimulants and sedatives

Overuse of stimulants and sedatives can adversely affect your health. Here are some basic rules to follow to help minimise the risks.

  • Use caffeine occasionally, and don't rely on it to keep you awake. 
  • When using caffeine or other stimulants, you should consider what might happen when the effects wear off, particularly when you are operating machinery or driving.
  • Avoid using alcohol to help with sleep. Although alcohol promotes sleepiness, it is also associated with earlier awakenings, disrupted sleep and poorer sleep quality.
  • Regular use of sleeping pills and other sedatives to aid sleep are not recommended.

Diet planning can help

Digestive problems are common in shift workers, due to both eating outside normal 'body clock' times, and poor diet. The tips below can help you better plan your meals to help you stay alert at work and to relax/sleep when you need to rest.


Regular light meals/snacks are less likely to affect alertness or cause drowsiness than a single heavy meal.Avoid drinking too much fluid (especially caffeine and alcohol) before sleeping as this may affect sleep.
Choose foods that are easy to digest such as rice, bread, salad, fruit, vegetables and milk products.Avoid fatty, spicy and/or heavy meals as these are more difficult to digest. They can make you feel drowsy when you need to be alert. They may also disturb sleep when you need to rest.
Fruit and vegetables are good snacks as their sugar is converted into energy relatively slowly and they also provide vitamins, minerals and fibre.Avoid sugary foods, such as biscuits, pastries, sweets – they provide a short-term energy boost followed by a dip in energy levels.
Drink plenty of water as dehydration can reduce both mental and physical performance.

Physical fitness and a healthier lifestyle

An unhealthy lifestyle, including overuse of stimulants and sedatives, combined with shift work can result in weight gain and other medical problems such as sleep disorders, diabetes, and heart disease. Maintaining a healthy diet, controlling use of stimulants and sedatives, and exercise can improve sleep quality, health and well-being.

Some other practical tips to create a healthier lifestyle are:

  • improving your fitness by spending 30 minutes a day on a physical activity.
  • eating healthy meals on a regular basis.
  • cutting down or giving up smoking.
  • reducing your alcohol intake.
  • seeking advice from your doctor if you require regular medication.

Further information on caffeine



Further diet information

Australian Dieticians Association

Healthy Workplaces Website - Eating Well

Further information on healthy lifestyles at work

Further information on healthy lifestyles in the workplace, or improving personal wellbeing can be found the Australian Government's Healthy Workers website or the Queensland Government's Healthier Workplaces website.

Last updated
29 May 2015