We look at how much water you should be drinking

By Bob Fear

We look at how much water you should be drinking

When it comes to knowing how much water we need to drink in a day it's hard to know who to believe. And then the answers sometimes lead to more questions, such as "Is this in addition to other food and drink? "And how big is a glass? I have huge ones!"

So we've scoured the web and collated 5 approaches for you to look over so you can decide which suites you best.

1) 2.5 – 3 litres a day

So say the World Health Organization. And they should know, right? Two - three litres a day seems to be the accepted rule. But they do caveat this with ‘depending on environmental conditions’ and ‘under normal circumstances’. 

Uh, but what’s ‘normal’? What ‘conditions’? Obviously this is a valiant catch-all attempt at giving every single person around the world one sound bit of clear, sensible advice. The trouble is that we're all different shapes and sizes, we all live different lifestyles in different parts of the world – can it really be the same for all of us?

2) 1.6 litres a day for women, 2 litres a day for men

The European Food Safety Authority sets a more conservative recommendation that is significantly less than what is suggested by the World Health Organization.

3) 1.2 litres a day

The UK's Food Standards Agency says this equates to about six to eight glasses but acknowledges that we need to drink more if it's hot. Even so, this is even less than the European Food Safety Authority (and no difference between men and women as far as they're concerned). 

4) The 8x8 rule (8 x 8 ounce glasses a day)

This is effectively the same as the 2-3 litres recommendation. But while investigating this for the BBC, Dr Chris Van Tulleken realised that supposedly scientific literature supporting this rule was, in fact, more marketing than research - the article was supported by a manufacturer of mineral water. 

Further to this, Heinz Valtin, MD tried to debunk this idea back in 2002 when he found no scientific evidence to support the 8x8 rule.

5) Only when I'm thirsty

Not to worry you or anything, but if you're feeling thirsty this could mean that it's too late - you've already become mildly dehydrated. The trick is: don't get dehydrated. It's not good for you. Simple.

The best way to tell if your body needs water is the colour and smell of your pee. 

  • Clear urine with no smell = well hydrated
  • Dark yellow to orangey/brown and smelly = dehydrated. 

So waiting 'til you're thirsty is not the best rule to follow, neither is waiting 'til you've got smelly brown pee - your objective is to always have lovely clear, odour-free pee. 

Which one is best for me?

Obviously by now we've realised there isn't a simple, straightforward answer for all. It's the old 'it depends' scenario.

“You don't need to worry about exactly what that total daily requirement is because your body will sort it all out for you. If you drink too much you pee it out. If you drink too little you get thirsty and pee less. It's all exquisitely well-controlled.” - Dr Chris Van Tulleken

But does this 'not too little, not too much' approach give us complete confidence? Or have we developed an unhealthy dependency for an 'expert' to prescribe exactly what to do and not trust our own bodies?

Ultimately, we have to listen to what our bodies tell us and use a little common sense to work out our own personal hydration needs based on gender, age, height, weight, geographical factors (temperature, altitude, humidity), sleep schedule, diet, types of beverages we consume, as well as activity and exercise patterns. 

So the answer is that there is no real answer: it's different for everyone and we need to work out what is best for us.

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