Prevent Dehydration & Keep Cool When Hiking


Dry mouth, dizziness, a pounding headache – these are the symptoms that fill every hiker with dread.

Staying cool and hydrated not only prevents discomfort, it also helps prevent more serious medical conditions, such as heatstroke.

Read on for our tips on what to bring, how to stay cool and hydrated, and how to recognise the symptoms of dehydration and heat stroke when hiking.

Filling up Garyl filter along a river

Drinking enough water is important, but there are other factors to keep in mind too. Image: Grayl

What to bring to keep cool and hydrated

1. Electrolyte tablets/powders

Replacing lost fluids is obviously essential. But that’s not all you need to replace. Electrolytes are very important for your body to maintain proper functioning.

Carry an electrolyte supplement, whether it be concentrate, powder or tab form with you at all times in your rucksack. Also, add salty snacks like nuts or pretzels to your hiking menu to help your body retain water.

If weight is a problem, then compact and lightweight electrolyte powders are the way to go. The Thorzt Solo Shots come in little 3g sachets which each makes 600ml of hydration drink. These are perfect as they take up minimal space. You can also get electrolytes supplements in tab form if that’s what you prefer.

Hikers putting a Nuun tablet into their drink bottle

Electrolytes are important, so incorporate them into your hydration routine. Image: Nuun

2. Easy-to-use hydration system

It’s important to remain motivated at all times to hydrate. This can be a little tricky when you’re exhausted and hot. If your current hydration system isn’t working for you, then definitely change it up.

Whether your bladder or reservoir is uncomfortable to use, or your soft bottle is too cumbersome – ensure that hydrating is as easy as possible so that it doesn’t fall by the wayside.

Man drinking from hydration pack

If the mouthpiece isn’t right, or the bottle isn’t comfy to hold then change it before your trip. Image: Kelly Thompson

3. Use a cooling necktie or towel

If you can’t find someone to follow you around and fan you with an oversized banana leaf, or your air conditioner is too bulky to fit in your rucksack – the next best thing is a Kool Tie.

Kool Ties are neckties that are filled with polymer crystals. All you need to do is soak them in water for 30-45 minutes, and the crystals will absorb the water. Then you then simply hang it around your neck, and the water will evaporate to cool you down. You could even wet a bandana or use a Chill Towel for a similar effect.

Man wearing Kool Tie while hiking

A Kool Tie is basically a personal evaporative cooling system. Image: Erin Wescombe

3. Instant ice packs

If you suspect that you or your hiking buddy has heat stroke, get them medical attention ASAP. In the meantime, you’ll need to attempt to cool them down. Seek out shade immediately, have them lie down, and then apply an instant ice pack to the back of their neck and under the arms if possible.

Instant ice packs are readily available at pharmacies or with larger first aid kits. If your kit is missing one, then definitely add it in.

Hiker putting Instant Ice Pack on his neck

An instant ice pack can cool you down in an emergency. Image: Erin Wescombe

How to avoid dehydration & stay cool

1. Drink before you start your hike each day

Anyone who’s completed a multi-day hike will tell you that drinking a litre of water every morning helps you stay on top of hydration. This way you’re not just replacing fluids just when your body needs them. For more on hydrating on a multi-day hike in hot and dry conditions, check out this article here.

Guardian Purifier by MSR

Drink water before you leave your campsite in the morning. Image: MSR

2. Wear appropriate clothing

Wear lightweight, loose, long sleeves to shield from the heat of the sun and keep you cool. It’s generally best to avoid fabrics such as cotton, as that fabric doesn’t wick away sweat. Instead, choose nylon or polyester fabric clothes that are designed especially for hiking.

Two men hiking the desert.

Longer sleeves may seem counterintuitive, but they’ll act as a shield. Image: Biolite

3. Seek out shade

This may not always be possible depending on the terrain, but when you’re stopping for a snack or rest break, do so in the shade. If you can coordinate your rest periods under a tree, you’ll be able to give your body a break from the sun.

Research the area in advance, and check out other blogs and forums to find where you can find shelter. Also, take a longer rest than you normally would when the weather is warm.

Resting in shade up on hill top

If shade is scarce, make the most of it when you see it. Image: Ben Collaton

4. Sun protection

You should wear sunscreen, sunglasses, and a hat to protect your skin. This will not only prevent UV damage and sunburn, it’ll also help shield you from the heat. If you’ve covered most of your exposed areas you also won’t have to wear as much sunscreen.

For shorter day hikes where you’ve got mobile reception, then one of the best apps to use is SunSmart. It tells you when the UV levels are high, will notify you when to reapply sunscreen, and gives you the UV levels of your location which will help protect you from the sun.

5. Get a head start

If you start your hike early, then you can finish in the early afternoon to avoid the hottest part of the day. If you spend less time in the heat, you won’t put your body through as much stress.

Hiking with Grayl water bottle early in morning.

If you set off early, you can beat the hottest part of the day. Image: Grayl

How to recognise dehydration

Here are some of the symptoms you should be aware of:

  • Infrequent urination
  • Dark small amounts of urine
  • A headache
  • Dry mouth
  • Dizziness
  • Rapid breathing

Symptoms of heat exhaustion

Take note of how your body is faring every step of the way, especially if you experience:

  • Confusion
  • Dark urine
  • Fatigue
  • A headache
  • Muscle or abdominal cramps
  • Nausea, vomiting or diarrhoea
  • Profuse sweating
  • Rapid heartbeat

Symptoms of heat stroke

Heat stroke is a very serious condition, so take note if you see anyone showing these signs:

  • Dizziness
  • Light-headedness
  • A throbbing headache
  • Lack of sweating despite the heat
  • Red, hot skin
  • Muscle weakness or cramps
  • Nausea and vomiting
  • Rapid, shallow breathing
  • Rapid heartbeat

Group hiking in hot weather

Some multi-day hikes like Larapinta or Kokoda are always warm, so prepare accordingly. Image: Eve Woods

Keep in mind that we are not medical experts here. We can only give you some guidelines about what to do and look out for in these situations.

If you have any medical conditions or requirements – then get in touch with your GP for more information. Before a multi-day hike, make sure you get the go-ahead from a medical professional.

If you like to explore off the beaten path a lot, it’s also worth updating your first aid skills. A PLB or satellite phone should also be on you at all times.

Stay cool, hydrated and safe on the trails

Whether you’re out in the heat at work, spending a day at the beach, or going for a ride or run – it’s essential that hydration is factored in.

You don’t want your well-planned adventure to go awry. So, pack the right gear, stay cool and keep hydrated. Happy hiking!


Have you ever experienced dehydration or heat stroke on the trail? How did you deal with it? 

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Joined back in December, 2016

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