Aqua vitae

I am a firm believer in the miraculous properties of water.

“I’ve got a headache” says Mrs RB – “Have you drunk enough water?” ask I.

“I’m feeling very tired today” – “Have some water, that will perk you up.”

“I was not feeling it on that run today” – “Did you take on fluids before you went?”

“I seem to have broken my leg” – “Er, have a glass of water whilst I phone for an ambulance.”

You see, it is the answer to most problems. It is therefore surprising that I am not always that great at following my own advice. Surprising, that is, until you realise that I am also a hypocrite. But water is, I believe, important and drinking the correct amount is therefore the Right Thing to do. The question that I found myself pondering was: how much is the correct amount?

I started at the Natural Hydration Council website (no, I hadn’t heard of them either). They introduce themselves as a “not for profit organisation dedicated to researching the science and communicating the facts about healthy hydration”. Their membership seems to be made up solely of bottled water companies so it is pretty easy to conclude that they may have a vested interest in us drinking more water, but I was prepared to have a look at what they had to say.

Their essential guide to hydration seemed like a good place to start.

What are we aiming for?

According to the above guide, we are aiming for something called optimal hydration. In simple terms, this is when the amount of water we take in matches our bodies’ requirements. If the amount we take in is less than what we need, then we become hypohydrated (or, in terms that I have heard of before, dehydrated); a condition where the body contains an inadequate volume of water for normal functioning.

Pancake layer 1

Pancake layer 1

Do you ever get muscle cramps?

There are quite a few symptoms of dehydration, including:

  • Muscle cramps
  • Headache
  • Sudden episodes of visual snow
  • Lowered blood pressure
  • Dizziness or fainting
  • Delirium
  • Unconsciousness
  • Swelling of the tongue
  • Death

(As defined in this presentation)

Admittedly, the last one may not just be an indicator of dehydration, but you get the idea. Our bodies try to guard us against these types of effects by controlling how much we urinate and by sending us messages to tell us that we are thirsty (this is surely not news to anyone). But if we don’t listen then it can catch up with us quickly.

So how much should we drink?

There is the standard answer to this, which is that this will depend on you, where you are and what you are doing. But that is not particularly helpful. The NHS website tells us that:

The European Food Safety Authority recommends that women should drink about 1.6 litres of fluid and men should drink about 2.0 litres of fluid per day. That’s about eight glasses of 200ml each for a woman, and 10 glasses of 200ml each for a man.

Which leads me to an important question: how big is a 200ml glass? It was time to line up the usual suspects…

Glasses

What does this tell us (other than the fact that we have some terrible tiles in our kitchen)? It tells me that none of my usual drinking accoutrements are exactly 200ml in capacity. For me, a man, my daily recommendation of 2.0 litres is:

  • 11 and a bit plastic water ‘glasses’; or
  • 9 1/2 cups from the coffee machine; or
  • 8 tumblers; or
  • 7 3/4 mugs; or
  • 7 half pint glasses; or
  • 3 1/2 pint glasses

Or any combination thereof.

Don’t want to worry about the size of your glasses?

Then the NHS has a pretty handy rule-of-thumb for you: “a good rule is to drink enough fluid so that you’re not thirsty for long periods, and to steadily increase your fluid intake when exercising and during hot weather.” I think even I can remember that one.

And what should we drink?

The NHS confirms that “all drinks count, including hot drinks such as tea and coffee, but water, milk and fruit juices are the healthiest” (and don’t forget that 150ml of fruit juice will count as one of your 5 a day). It also reminds us that it is sensible to avoid “sugary, soft and fizzy drinks that can be high in added sugars. These can be high in calories and bad for teeth.”

Here in the UK we can barely stop the water from pouring down on us, so it is worth remembering that water is “the healthiest choice for quenching your thirst at any time. It has no calories and contains no sugars that can damage teeth.” (NHS)

And everyone agrees…

Of course they don’t. It seems that there is no such thing as a simple answer.

This 2013 BBC article advocates a “not too little and not too much” approach, but it focusses on the “not too much” part of the argument, warning against overdoing the hydration (a condition known as hyperhydration). The key sections of this article, in my opinion, run as follows:

There is a very well accepted idea that we should drink about eight cups of water per day (two to three litres) in addition to our food and other drinks.

[But] there is no evidence that adding the eight cups of water to everything else you drink will do you any good and it could do you harm.

This seems to fly in the face of what we have been told, so it warrants a little more thinking about.

The water of things

We need to bear in mind, in my unscientific opinion, that we do not just get our water intake from the water that we take in. Putting it more scientifically, as the European Food Safety Authority are wont to do:

Water is consumed from different sources, which include drinking water (tap and bottled water), beverages, moisture content of foods, and water produced by oxidative processes in the body. Water intake from beverages and foods is defined as total water intake, while the sum of total water intake and oxidation water constitutes total available water.

Meaning that our total water intake is made up of the drinks we consume plus the water in the food we eat. And then, on top of that, there is the water we produce ourselves through all of the clever things that happen at a cellular level within our bodies. For their reference values for water intake, the EFSA decided that they should include “water from drinking water, beverages of all kind, and from food moisture” (meaning that they are, quite sensibly, not worrying about the water we produce ourselves). The reference values they recommend are:

Adequate total water intakes for females would have to be 2.0 L/day… and for males 2.5 L/day

(Applying to “conditions of moderate environmental temperature and moderate physical activity levels”)

If you dive into the detail of the EFSA report (and I would understand why you wouldn’t want to), then they make an assumption (section 6.6 on page 38, for you sadists out there) that 80% of your water intake comes from beverages. This reduces the above recommendation for water intake to come from the drinks we drink, down to 1.6 litres per day for females and 2.0 litres for males.

Which is what it says up there near the top of this post. Or, in other words, the earlier recommendation from the NHS/EFSA has already taken into account the fact that you are getting some of your water intake from your food, and discounted that element from the amount it recommends you drink each day.

But it also confirms that the EFSA has allowed for “drinking water [and] beverages of all kind” within their recommendation for a person’s daily intake (their reference value for water intake). This means that it is not, as the BBC article suggests, recommending 2.0 litres “in addition to our… other drinks”. Rather, it is 2.0 litres (for a man) from water and other drinks.

I don’t know about you, but I could do with a stiff drink

All of that scientific pondering has left me with a thirst, but I do feel that it has been worthwhile. I have come to the conclusion (and I would always encourage you to draw your own) that I am going to try, on a normal day, to drink somewhere around 2.0 litres. Knowing me, that is likely to be made up of a combination of water, coffee and orange juice (but not all at the same time, you understand). On days when I am more active, I will drink a bit more.

That seems to be reasonably straightforward and is, I hope, the Right Thing for me to do.


Running Buffet is not run by a health expert, nor a food scientist. I did once get a food hygiene qualification but that was a long time ago and I have since lost the certificate. I am, instead, an enthusiastic amateur. So please do not rely solely on anything I have to say in these posts, but you may be able to use them as a starting point, a jumping-off point, from which to build up your own opinions on what is right and what is not. I will provide links to various websites, but please be aware that I am not responsible for those sites, nor do I necessarily agree with what they say.

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3 thoughts on “Aqua vitae

  1. Great post.
    I drink water all day and have no idea how much, but probably well over the 2L mark. I’ve read that each 8 ounce glass of ice water burns 10 calories. So I always drink ice-cold water.
    I’ve wondered about the water produced in our bodies through normal processes. I’ve read that each gram of carbohydrates holds onto 4 grams of water when our body stores it. So when we burn off a gram, 4 grams of water are released into our systems.
    From experience it would appear that this internally released water is far from enough to sustain us during a run.

    • Thanks Andy.

      Drinking water certainly seems as though it is the best option. I probably lean too much towards coffee at the moment and that is something I should look into further.

      That is interesting about the stored water. I must admit that I saw a few things about that side of it when reading up about hydration online but I didn’t delve too far into it. It would be interesting to explore – I will see how far my school-level science gets me!

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