Wednesday, 18 January 2017

Real Health | Hydration - What should we be drinking?

After the positive reception to the introduction of my 'Real Health' series, I'm bringing the first of my posts discussing the health advice, hints and tips going around. As I said in the introduction, we're tending towards overcomplicating our ideas of what it means to be healthy, making it feel like achieving the near-impossible. My aim with this series is to break down the ideas that health is something for everyone, not an extra hobby or activity for when we've got the time...

Glass of water on pile of magazines


So, hands up who's ever resolved to "drink more water"? 

Why was that? Is it because you genuinely find yourself thirsty throughout the day? Or is it that you once (or twice, or many times) read in an article somewhere that you should be drinking two to three litres of water a day?

As I started writing this post, I googled "drinking two litres of water a day". The number one result? A popular women's magazine with an article about the skin changes one woman perceived after drinking three litres of water. Nothing scientific, she just thought the water "had done something." 

There is tonnes of writing out there about why we should be drinking more water - everything from flushing out toxins and aiding weight loss, to improving concentration and brightening skin.

Glass of water on wooden surface

The Official Advice

Now, it's true that Public Health England's Eatwell Guide does suggest drinking 6 to 8 glasses of fluid a day. 

And yes, fluids are important for maintaining healthy functioning of the human body. But we're all different. We all have slightly different metabolic rates, we have different levels of activity and we spend our days in a huge variety of environments. Studies have been done to try and come up with an answer to exactly what we need, but there are so many variables it's difficult to come up with a perfect answer. Producing health advice that is both accurate and simple to follow is a further challenge. That's why it's a guide and not steadfast rules. 6 to 8 glasses, are nice round numbers that can more or less be applied to most people but that doesn't mean it's the target for everyone to aim for.

Filling glass of water from tap

So what do we need?

As I said, it's pretty much impossible to come up with the perfect number. What we need on a cold day when we're not doing very much is going to be entirely different to what we need running around on a hot day. 

Even when I'm working in the hospital, I still have to estimate what people need. Generally we work off the idea that the average, healthy person will need 25-30ml/kg/24hr. This is a very rough guide, simply because we need something to work from. And that's for fluid from food and drink! 

If you're feeling thirsty, tired, dizzy or your urine's getting dark these can all be signs that you're not getting enough hydration. But if you're feeling alright, chances are you've got nothing to worry about.

The body can regulate fluids all on it's own!

Our bodies are pretty good at regulating fluids. This isn't a physiology lesson so I'm not going to go into the details of the various hormones, receptors and how the kidneys function - but take my word for it that our bodies are pretty used to coping! It's just balancing what goes in with what comes out. 

Did you count every glass of water you drank each day when you were a child? Our whole life, our bodies have been getting by just fine, doing their own thing. When we need more water, we feel thirsty. It's kind of as easy as that really. So there's no need to suddenly decide one day that we're going to start drinking loads more. Honestly, our brain knows our requirements better than some healthy living article does!

Just to emphasise this point further, one of the routine blood tests we do on pretty much everyone who comes to hospital is one to check levels of electrolytes in the blood. It's a good marker for hydration and whether the kidneys are functioning alright. I almost never see a young person with any evidence of dehydration. And I'm willing to bet that the people who come through the hospital doors are not the people religiously sticking to drinking lots of water every day... Young people's bodies are particularly good at regulating fluids.

If we're drinking more water than we need, our kidneys will just produce more urine to get rid of the excess. You can't try to make your body use more! (And yes, it's rare but it is possible to drink too much. Overdoing it can drop the levels of sodium in your blood which can cause confusion, irritability, seizures and coma). 

As for all the 'beauty benefits' of water - that comes from just getting our hydration right, not from extra fluid! So yes, if you've been a bit dehydrated, increasing your intake will make you feel better but it might not take quite as much as you think.

Where should we get fluid from then?

Earlier on I said that fluid comes from food and drink. So our daily requirements don't have to come entirely from glasses of water! Eating a balanced diet with a selection of fruit and vegetables is a good start to getting our hydration right. And all drinks count; water, fruit juice, fizzy drinks, tea, coffee, milk... 

We don't need to be carrying round two litres of water to try and drink on top of anything else we're already having!

Now increasing water intake by swapping out less healthy choices isn't a bad idea. If you're currently keeping hydrated purely on fizzy drinks for instance, changing some of those for water will have benefits in terms of sugar intake and healthy teeth. Similarly, lots of caffeine can worsen anxiety - so drinking water instead of coffee now and again is good too.

Glass of carrot, apple and ginger juice

Drinks cartons in fridge

So in conclusion...

There's really no need to overthink how much water we're drinking. Calculating exact requirements and trying to keep track of what we take in during the day just isn't necessary.  If you feel thirsty, then you need to drink. So long as you're not constantly ignoring when you physically feel thirsty, you're probably doing alright. Simple, no? 

Just to note...

Everyone is different. I've written this based very generally on average, healthy people. This is intended to be discussion only and should not be taken as official medical advice. If you are concerned about your health, you should seek medical advice from your own doctor, NHS 111 service or attend A&E if it's an emergency. Plenty more information can be found on the NHS website.



  1. I'm loving this little series! I'm not going to lie, I have started drinking a 500ml bottle of water as soon as I wake up this year but that's because before I was drinking coffee and felt dehydrated - so listening to my body more than fad diets. This is great advice though :) xx

    Sam // What I Know Now

    1. Glad you're enjoying the posts! I think you're right - it's definitely better to be listening to your body and doing what works for you personally, rather than sticking to an arbitrary number made up by someone else! xx

  2. I loved reading this post! I try and stick to water during the working day, and just drink when I feel like I need it. I don't have the time to count how much I drink; I just drink when I am needing it. I love water, especially when it is cold, because it works wonders! If I am feeling tired at work, I'll grab a cold water as I find it helps to wake me up too. Thanks for this series, very interesting!

    Suitcase and Sandals Blog XX

  3. This is a sensible post and thanks! I go for 3 liters of water based on my activities and body weight and my body is loving it! Before, I was too lazy to drink water, prefering sodas and sugary drink. Today, I know better! I even put some lemon and cucumber in my water to make it more refreshing and satisfying. Plus, there's tremendous benefits, too. Making your own infused beverage is not only healthy but inexpensive, as well. There's a lot of recipes out there for these infused drinks, starting with this great guide


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