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Fluid

Fluids are essential to us. Water fills the spaces in and between our cells as well playing a vital role in the digestion and absorption of all the food we eat. Fluids also help to keep our body temperature within safe limits.

How much fluid do we need?

We need to make sure that our bodies stay hydrated, especially in hot weather, when exercising or playing sport.  The amount needed varies according to your age, size, the weather and how active you are. Fluid comes from all we drink as well as many everyday foods (for example, watermelon and lettuce have a high water content).

So how much should we be drinking to stay hydrated? Your body will tell you by feeling thirsty- even feeling slightly thirst is a sign to drink some water!

As a rough guide, adult women should aim for 2.3 L (8 cups) and men, 2.6 L (10 cups) of fluid each day and children 1 – 1.6 L (4-6 cups). This includes all drinks, including those listed below, and water. You will need more

  • when exercising or playing a lot of sport
  • during pregnancy (~2.3 L) and even more so when breastfeeding (~2.6 L)

The best test to check that you are adequately hydrated is that you go to the toilet regularly and by checking the colour of your urine (pee)

  • pale yellow= hydrated
  • dark yellow= dehydrated
  • looks like water= overhydrated

In older age, your thirst signals actually decrease even though your body still needs the water, therefore, it becomes even more so important to check that you are going to the toilet regularly and to check the colour of your pee.

Fluids we commonly drink

  • Water In New Zealand, tap water is cheap, readily available and doesn’t contain any kilojoules. It is the best liquid for hydrating your body.
  • Fruit juices usually have as much sugar as soft (fizzy) drinks, so should not be relied upon for re-hydrating.
  • Soft drinks, energy, sports and powdered drinks, and cordials all contain sugar and very little else in the way of nutrients. They are best reserved on an occasional basis, especially if you are watching your weight, as they are very high in energy (kilojoules/calories).
  • Milk and water are recommended as the best drinks for children. Milk contains valuable nutrients – calcium, proteinvitamins and minerals – and because it has a low glycaemic index (GI) it is filling. Low-fat or reduced-fat options are suitable for children older than two years of age. For children between one and two years Flavoured milk still contain loads of beneficial nutrients but are higher in sugar than ordinary milk – check the label and choose the one that is lowest in fat and sugar.
  • Tea and coffee are popular drinks for many people, both for taste and the fact they are low in kilojoules/calories (before you add milk and sugar). Black and green teas and coffee all contain antioxidants beneficial for our health. Both tea and coffee contain caffeine, which stimulates the central nervous system. Coffee can have a dehydrating (diuretic) effect though, so is not a suitable drink when rehydrating before or after exercise.
  • Alcohol has a strong dehydrating effect, so should not be considered part of your daily fluid intake.

Tips for drinking plenty of fluids

  • Water and milk are the best drinks to offer children
  • Keep a jug of water in the fridge so that chilled water is easily available to all the family. Flavour with slices of lemon or lime.
  • When away from home, take a bottle of water with you
  • Keep juices and fizzy drinks for special occasions, not every day.
  • When drinking alcohol, have water as well to counter alcohol’s strong dehydrating effect.

More info:

Water Health Navigator NZ

Water Nutrient Reference Values for Australia and NZ

Last modified: January 28, 2022