Yes, it’s quite warm at the moment. No, I won’t go on and on about it like everyone else is. But sweating my way up a mountain the other day started me thinking about the wet stuff…


Something that often gets overlooked when we are packing a rucksack for a day or more in the hills is water. It’s fairly obvious that we need to take something to drink… but how much? How best to carry it? Water, or something else? Most people settle on a system after a few trips but it’s always worth taking a look at the other options available!

Everybody has different requirements due to variations in physiology, health and metabolic rates. It also varies with the level of activity, the weather on the day and how knackered you are from the day before! I am not an expert by any means but I’ve been working in the outdoors for a number of years, and been ‘buggering around’ doing outdoorsy stuff for even longer and I think I’ve probably tried most ways of carrying fluid and getting into the body. Having said that, let’s have a look at some essential facts:

Each day the average adult mooching about not doing much will lose about 2.5 litres (L) of water. That’s 1.5L through the kidneys, 0.35L through moisture in the breath,  0.45L through sweat and 0.2L down the loo in your daily bowel movement! Broadly speaking, to avoid dehydration you need to take in at least as much water as you put out. Obviously most of this comes from drinking fluids, but some (0.7L) comes from food and roughly 0.3L is actually made BY the body in biochemical reactions. Great! Fantastic! But what about walking uphill for hours on end?

Whilst walking/running etc we don’t just lose fluid through sweat, a good deal is used by the muscles and recirculated back to the kidneys. So the harder you work, the more you use. For a walk of about 7 hours over rough terrain in a temperate climate (about 12ºC-20ºC) you’ll use a staggering 3-6 litres of water! Combine that with the loss of vital salts and minerals through sweat and you’ll soon understand that carrying the correct amount of water is quite important for walkers!
The effects of dehydration can vary from just feeling a bit tired to headaches, muscle weakness, nauseau, light headedness, vomiting and eventually a lack of life… It’s important you keep an eye on your health as you go, and note the colour of your urine during pee-stops (admittedly easier for men than women). You want to have something about the same colour as lemon barley water or flat champagne. If it’s darker then you need to start taking more water on board. Rehydration powders and drinks are useful, but try and look for unsweetened ones and drink them at the correct concentration. Yes, they do taste like crap…

In spring/summer I try and take AT LEAST two litres of water with me for a long-ish hill day (5-8hrs walking) in a hydration bladder in my rucksack. For a hotter day when the sun is shining and the wind isn’t up to much I’ll probably increase that to about three litres, with the extra litre in a seperate bottle so I can keep an eye on how much I have left. If I know that I’ll be passing places where I can safely fill up then I’ll just take an empty bottle and fill up as I go. I’ll also try and make sure I drink ALL of that water by the end of the walk as carrying it but not drinking it is a bit daft.
In winter I’ll try and stick to two litres, with maybe another 0.5L of hot fluid in a flask. Just becasue it’s cold doesn’t mean you aren’t getting through the same amount of fluids!

My slightly-battered 3.0L Source hydration bladder

What’s the best way to carry water in a rucksack? Hydration bladders, such as the ones made by Source are probably my favourite. They allow you to drink on the move, don’t dig into your back and if you keep them in the freezer between uses you should never need to properly clean them out. The Source ones are also very well designed, with a mouthpiece that doesn’t keep falling off and a cover to keep the muck off the end. Water bottles come in a huge variety of shapes and sizes, but I like the ones made by Sigg and Nalgene as they are fairly indestructible. It is also worth remembering that you get a very tough and reliable water bottle free with every ourchase of mineral water etc!

If you want to find out more, why not come along on one of our Mountaincraft courses? You’ll learn basic skills such as how much water to carry, equipment choice, movement skills over tough ground, navigation and what to do in an emergency, all expertly delivered by qualified and experienced professionals:

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