The age old question “how much water should I drink?” is not an easily answered one, there are so many factors that contribute to water loss and retention, but considering our bodies are largely made up of the stuff, we really should make sure we drink enough. Most of the time we hear that 8 glasses of water is the target, however this really doesn’t account for body weight, mass, exercise levels, disease states and amount of water consumed from our diets. So lets delve a little deeper…

Water in our bodies:

Water is the most vital component of our bodies, with every single one of our cells needing it for survival. We require it to help eliminate waste products and toxins, carry nutrients and oxygen to our cells, cushion our nervous system, lubricate joints, regulate our body temperature and of course keep our little cells happy and hydrated!


Most of us walk around in a state of constant dehydrate without knowing, often we mistake our thirst for hunger. Dehydration can lead to headaches, dry mouth, low energy levels, muscle cramps, constipation, digestive upsets, and flushed skin. In extreme cases it will lead to dizziness, mental changes and unconsciousness. And surprisingly thirst can happen even when we are not hot and sweating-it can also happen in cold climates such as while skiing. 

When do we need more?

There are a number of circumstances that its super important to keep up our intake, these are when we are most at risk of dehydration. Dehydrating environments (such as air-conditioned offices and planes) contribute to dehydration, as well as hot and dry weather, outside during sporting events, at the beach in full sun (I hope you are also wearing plenty of sunscreen!), during endurance events, various illness and disease states, and while pregnant and breastfeeding. A high protein diet is another circumstance where dehydration may be an issue, with the kidney needing to work extra hard to get rid of the metabolic waste products from excessive protein intake. 


So what is ‘enough’ water?

Well, as I said it depends on a number of things, and the best way of doing it is listening to your body and learning what being well hydrated feels like. My best estimate is one based off body weight:

35mL x body weight in kg

So based on that, an individual that weighs 70kg would need to drink:
35mL x 70kg = 2450mL (or 2.45L)

If you are exercising lots, or will be in air-conditioning for long period, you will most likely need more, if you are breastfeeding, drink more. And while other beverages may contribute to water intake, water is always best as it doesn’t contain empty kilojoules (energy without nutrients) and will immediately begin to rehydrate you. Coffee has been said to be a diuretic (Something which causes us to urinate more frequently and therefore loose water), however the actual effect of this is very small. Coffee and tea can contribute to your overall fluid intake, but remember that high levels of caffeine are also detrimental to your health. 

Another aspect of course, is the water content of our food. So for example, fruits and vegetables contain high levels of water content, so help to contribute to our overall water intake. All the more reason to get your 2 and 5 everyday! If you are not currently consuming the recommended amounts of fruit and veg, then you will definitely want to be getting plenty of water, aim for the full amount needed for your body weight. 

On a final note, the easiest way to make sure you are getting enough fluids, is to simply drink water. While in rare cases you can drink too much, drinking 3 litres a day isn’t going to get you there, and more water will be beneficial to your thirsty cells. I have a big 1 litre drink bottle, that I make sure I finish before lunch, then fill up again at lunch. After I have finished those 2 litres, anything else is a bonus!