How to stay hydrated when hiking

Pack like a camel for your hiking trip, and always have more water in reserve than you think you need – find out everything you need to know about staying hydrated when hiking.

How to stay hydrated when hiking

We can sweat between three and four litres of water per hour when hiking, and that liquid needs to be replaced.

Dehydration is a serious matter and it won’t just leave you feeling thirsty or lethargic – chronic dehydration can damage your muscles, cause constipation and even lead to kidney disease. So how can we stay hydrated when hiking, and how do we know how much we should be drinking?

How much should I drink when hiking?

The average adult male should drink 3.7 litres of water a day, and an adult female 2.7 litres. Bearing in mind that strenuous exercise can cause you to sweat out your entire daily goal in an hour, which means you’ll need to drink a lot more to compensate.

You also need to consider the weather. Exercising in the heat can cause you to sweat 10 to 20% more, or to lose an extra 200-300 millilitres an hour. 

Head hurting from all the maths? A general rule of thumb is to make sure you have 500 millilitres of water per hour you plan to be hiking. If it’s particularly hot, or a particularly tough trail, increase this as needed.

Editor’s notes

Drinking enough (water, that is) is one of the most important aspects when heading out for a hike. Learn how much to drink, how much water to take and find products you can use to filter and purify water on your next long-distance walk.

How do I carry all that water?

It’s easy to provide figures on the water you should be drinking, but with each litre weighing around a kilogram, it’s unlikely that you’ll be carrying a full day’s worth of water on your back (not to mention extra for cooking). 

It’s important to plan according to your environment here – if you’re an ultralight hiker passing endless rivers and lakes, you might be able to take a small bottle and carry a filter like the Lifestraw (newly updated for 2022) to drink straight from the source. 

Otherwise, we simply recommend packing as much as possible, evenly distributing the weight on your pack and between your hiking group. A hydration backpack is a great way to manage your personal water source.

Should I purify or filter water?

On most trips, you should plan to purify or filter water as you go. 

We purify and/or filter water for five main reasons: to get rid of viruses, chemical pollutants, bacteria, parasites and turbidity (which is the mud, silt and foliage that clouds up your water). In countries where sewage systems are less advanced, you should almost always purify your water as this will stop you from contracting waterborne viruses and parasites. If you’re sure that the water you’re drinking is clean, and the silt is just making it look unappetising or taste gritty, simply filtering it is enough. 

Lifestraw Peak Series Collapsible Squeeze Bottle Product Image

Top pickLifestraw Peak Series Collapsible Squeeze Bottle

With 1L of collapsible capacity, the Lifestraw Peak Series Collapsible Squeeze Bottle should be on the wish list of every backpacker. 

A hard, plastic bottle with a wide lip makes water collection from streams and lakes easier. A good filter straw/bottle combination is the Lifestraw Squeeze Bottle,  but be aware that the filter straw is just a filter, and not a purifier. We have plenty of tips on purifying water in the wild to help you.

Be aware that even in countries with advanced sewage systems, it’s not always evident whether water is contaminated or not. A stream may look crystal clear, but if an animal has defecated (or even died) further upstream, you risk catching something nasty. Simple water purification tablets like these from Oasis purify a litre of water per pill and take just half an hour to do so, but they make your beverage taste a little like swimming pools.

Other hiking hydration solutions

Water is the best option to keep you hydrated when hiking – other drinks like fruit juice and squash will not be as effective. 

When we sweat, 99% of what we lose is water, but 1% is electrolytes. Electrolytes are produced by sodium, potassium, calcium and magnesium in our bodies, and although compared to water the electrolytes we’re losing are minimal, you can help to replace them using sports tablets

It’s also recommended to eat foods with a high water content to remain hydrated when out on the trails. Particularly good options include cucumber, celery and radishes, which have a water content of over 90%.

What if I’m not thirsty? 

Even if you don’t feel thirsty when hiking, it’s important to continue drinking plenty of liquids. If you haven’t drunk much throughout the day but you’re not thirsty, it could be because the weather is cold, you’re at altitude, or both. It’s important to make sure you’re drinking enough all the same. 

How can I tell if I’m dehydrated?

Early signs of dehydration are a dry mouth or feeling lethargic. You may also notice that your urine is darker than usual. As dehydration progresses, you might experience stomach cramps, headaches and nausea. 

Drink water as soon as you feel signs of dehydration and remember that prolonged exposure to the sun, and sunburn, can dehydrate you further. Try to stay out of the sun, cover exposed areas of skin, wear a hat and coat up with sun cream.

How can I ensure I don’t run out of water?

Always keep a small bottle of water in reserve in case of emergencies. Plan thoroughly and familiarise yourself with the landscape, always packing a little more water than you think you’ll need. 

If you’re going to be hiking for four hours but you’re not sure you’ll pass a water source, instead of taking the recommended two litres (500 millilitres per hour), take three so you’ve got some in reserve.

Is it possible to overhydrate?

Yes, and it’s particularly common in athletes. Overhydration causes your sodium levels to drop and throws your electrolyte balance off. Signs of overhydration include needing to urinate more than 10 times a day, weak and shaky muscles, and swollen hands, feet or lips. 

Make sure to regularly check the colour of your urine, which should be light yellow rather than consistently transparent. It should be noted that in most cases your kidneys will excrete water if you overhydrate unless you have a condition that prevents them from doing so. 

An adult with healthy kidneys would have to regularly drink around 23 litres of water a day to interfere with their kidneys’ function to excrete water, so don’t let overhydration become a preoccupation, it’s highly unlikely you’ll be overhydrating on a hike!

Looking for more tips on how to stay hydrated when hiking? Reach out to us on Instagram – @advpending.

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