Everything you need to know about dehydration and how to avoid it 

Young man sweating from exercise

In Queensland, we often talk about dehydration in relation to the elderly, children and babies, or during extreme heatwaves. But the reality is dehydration can affect any Queenslander at any time of year. 

Queensland is known for its warm weather, with sunny summers and mild winters. With a variety of natural spaces to explore, from beaches to the bush and outback, Queensland is a great place to get outdoors and get active.

Understanding what dehydration is, how to know if you are dehydrated and how to treat and prevent dehydration will help you enjoy Queensland safely. 

What is dehydration? 

Dehydration happens when the body loses too much water. Your body loses water by sweating, going to the toilet and by breathing out tiny water particles when you exhale. Vomiting and diarrhoea can also see the body lose larger amounts of water. 

Normally, you’re easily able to replace this water with foods and drinks. Dehydration happens when water is not replaced quickly enough to make up for water that is lost. 

Elderly man drinks a glass of water in his kitchen

How can dehydration happen? 

It can be surprisingly easy to become dehydrated. 

If you don’t rehydrate regularly, you could become dehydrated if you: 

  • do exercise that is strenuous, prolonged or makes you very sweaty 
  • do manual work or work in a hot environment 
  • spend time in a hot or poorly ventilated indoor environment, like a heated gym, roof space or hot warehouse 
  • spend time in a dry environment, like a long-haul plane flight 
  • or spend time without access to water. 

Dehydration can also occur in windy environments, which allow sweat to evaporate more quickly. 

Of course, doing any of these activities on a hot day will see you getting even hotter and sweatier. But it’s also important to pay attention to rehydration during cooler months, when you might not feel like drinking enough water and heated air can dry your skin. 

You can also become dehydrated from drinking alcohol or drinks that have caffeine in them, both of which act as a diuretic. This means that they make you go to the toilet more often, losing more water than normal. 

How do I know if I am dehydrated?

If you are mildly dehydrated, you might experience one or more of these symptoms: 

  • thirstiness 
  • a dry mouth, lips and tongue 
  • headache 
  • have urine that is a darker yellow than usual, and less of it 
  • light-headedness or dizziness. 

If you are severely dehydrated, you might experience one or more of these symptoms: 

  • extreme thirstiness 
  • have a very dry mouth, lips and tongue 
  • crankiness 
  • drowsiness 
  • feel like you are breathing very quickly 
  • have a fast heart rate 
  • fainting 
  • have very little or no urine. 

If you weigh more than 1 kilogram less after exercising or working, you are likely to be dehydrated. 


What happens if I don’t treat dehydration? 

Not treating dehydration can have serious, even deadly, consequences. Your body is made up of approximately 50 – 75% water and not having enough of it affects a large number of bodily functions. Dehydration can lead to other heat related illnesses like heat exhaustion and heat stroke, which can occur rapidly and can be fatal. 

How to treat mild dehydration 

For mild dehydration, the best thing you can do is drink water to rehydrate. Drink small amounts of water regularly and try to avoid alcoholic or caffeinated drinks. 

How to treat severe dehydration 

If someone is severely dehydrated, they need to seek medical treatment immediately. Call 000 if you, or a person you are caring for, is feeling very unwell or displaying signs of heat stroke

How to prevent dehydration 

You can follow these steps every day to help prevent dehydration: 

  • drink plain water often and keep track of how much you drink
  • have a big glass of water as soon as you wake up, to rehydrate your body after sleep
  • always carry water with you when you leave the house – use a BPA-free or stainless steel water bottle 
  • seek cool or shady places when you are out of the house 
  • be mindful of dehydration when doing outdoor activities 
  • drink extra water on hot days 
  • Pay attention to signals from your body such as feeling thirsty and the colour of urine

How much water should you drink each day? 

Try to drink enough water every day, even if it isn’t hot or you aren’t doing a lot of exercise. Men should drink 2.6 litres (10 cups) of fluid each day. Women should drink 2.1 litres (8 cups) of fluid each day. If you are exercising, sweating a lot, or are in a hot environment, you will need to drink even more than this to make up for the water you are losing.  

If you have questions about how much fluid you should drink, or if you have any medical conditions or are taking any medications that might change your fluid requirements, talk to your doctor about how much fluid you need. 

What about sports drinks?

Sports drinks that contain electrolytes are not necessary for rehydration unless you’re doing physical activity that’s at least moderate intensity and exceeds 1 hour. Sports drinks are often marketed as ‘health drinks,’ but are usually high in sugar. Drinking plain water, especially during and after light and moderate intensity physical activity, is perfectly fine. 

You might also want to consider cutting out other sugary drinks, like soft drinks, iced teas and energy drinks. Try adding fresh fruit, veggies and herbs to your water instead to boost the flavour in a healthy way. 

Can I drink too much water? 

Excessive water intake can cause a rare condition called hyponatraemia. Hyponatraemia happens when very large quantities of plain water are drunk quickly, diluting the level of sodium in the blood. 

If you are dehydrated, drink small amounts of water regularly to give your body time to process it, rather than drinking a lot of fluid in a short space of time.