Hiking in extreme heat

Hiking in extreme heat can be dangerous. The damage we can do to our bodies when we exert ourselves in high temperatures is serious, plus it makes the hike not a whole lot of fun. You’ve probably been dehydrated at least once before, but this can lead to heat exhaustion and heat stroke quite quickly if left untreated.

While you probably wouldn’t choose to hike in extreme heat, sometimes it’s unavoidable. Whether it’s the season or the location’s climate, you might have to face some hot weather on a scheduled hike. Treks like the Jatbula Trail and Southern Walks in Nitmiluk National Park are almost always undertaken in hot weather, simply due to the climate of the Top End in Australia. This means you need to be prepared and ready to get yourself through the hike safely.

I suffered heat exhaustion while doing the Southern Walks in Nitmiluk and it was a very unpleasant experience as I had to walk myself out over the three day hike while not feeling very well at all. I then faced extreme heat again a few weeks later on the Jatbula Trail, and handled it much better. So, I figured I’d put together a guide to surviving walking in extreme heat to help others manage hiking in summer or hot weather.

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What Happens When We Hike in Hot Weather?

The human body is pretty cool. It can survive so many extremes and physical challenges that we put it through. But, of course, there is a limit.

Humans have adapted to survive with an average core body temperature of around 37 degrees. If we get too cold we can suffer from hypothermia, but too hot and it becomes hyperthermia. 

When the outside temperature sits anywhere between 20 and 25 degrees, our bodies are pretty happy maintaining normal functions. But once things get warmer than that, our body starts to kick in some processes to try and cool us: sweating and blood vessel dilation.

However, even these bodily processes have their limits too. The evaporation of sweat from our skin will help cool us down, but there can be a point when it can’t evaporate properly, and our core temperature will just keep ticking upwards. This is more common in humid conditions or at times when you’re not getting much airflow. For this reason, humidity can be more telling of dangerous conditions than simply temperature. For example, a humid 35 degrees will likely be more lethal than a dry 40 degrees. 

At the extreme end, once our body temperature gets too high, our cells start to collapse and die. This is basically like our body literally cooking in the heat. 

At the same time, our body will try to pump more blood to the skin, which means our central blood pressure will go down. To compensate for this, our heart rate will climb as it tries to pump blood around everywhere it needs to go. This simply puts more stress on our vital organs.

All of this leads to a few heat-related illnesses, if not managed properly.

Hikers on Jatbula trail
Jatbula Trail

Dehydration

At a basic level, dehydration is the excess loss of liquid or fluid from the body. While it can happen during a number of circumstances, when it comes to hiking in extreme heat, it’s generally due to excess sweating, inadequate fluid intake and overexertion.

Darker urine is a sign you’re dehydrated. This can also lead to other symptoms, including cramps, exhaustion and feeling light-headed or having a headache. If ignored in hot conditions, it can lead to other heat-related illnesses including heat exhaustion and heat stroke.

At the same time, it’s important not to drink too much water. If your urine has no colour at all, it means you’re drinking too much and diluting your sodium levels, which can be just as dangerous. 

On top of 17 Mile Falls
Resting on top of 17 Mile Falls (Jatbula Trail)

Heat Exhaustion

Heat exhaustion is basically your body’s inability to cope with the stress of heat. It generally occurs after lengthy exposure to high temperatures and is usually accompanied with dehydration. While this is not an emergency, it’s a condition that can worsen quickly if not treated, managed or reacted upon.

The initial symptoms can be:

  • Heavy sweating
  • Rapid pulse
  • Nausea
  • Muscle cramps
  • Irritability 
  • Dizziness
  • Fatigue 
  • Headache

Heat Stroke

Heatstroke is a medical emergency. It happens when the body temperature is at a critical level and your body is literally overheating or cooking. Effectively, heat stroke can quickly lead to a heart attack, even in otherwise healthy individuals because the stress on our bodies becomes too great. Or, it will also lead to damage to the kidneys or other organs. 

The initial symptoms can be:

  • Skin gets red hot
  • Dry, swollen tongue
  • Intense thirst
  • Nausea and vomiting
  • Throbbing headache
  • Brain fog or disorientation 
  • Typically, no longer sweating

It can lead to:

  • Seizures
  • Loss of consciousness 
  • Organ damage
  • Heart attack
Solo hiking Southern Walks Nitmiluk
Southern Walks – Nitmiluk National Park

Tips for Hiking in Extreme Heat

Now that we know what can happen to our bodies when we go off walking in the heat, let’s take a look at how to avoid some of these heat-related illnesses and conditions. While it’s best to reschedule your hike if it’s going to be over 30 degrees, sometimes you simply can’t due to campsite bookings and logistics.

These tips for hiking in the heat will help you get through your next summer hiking trip much more easily and safely.

1. Acclimatise Yourself to the Heat

It is possible to get used to heat. There are body adaptations that come into effect once you’re exposed to something continuously. However, it’s thought that it would take around 10 consecutive days of exposure to extreme heat for your body to fully acclimatise. 

This might not be possible if you’re travelling to do a hike, like the Jatbula Trail for example. If you’re coming from somewhere colder, you may not have the time to acclimatise yourself. But, if you do have the time, it really helps to spend more time in the conditions you’ll be hiking in.

I certainly felt a lot better on the Jatbula Trail than I did on the Southern Walks, because there was more than a month in between and I’d stayed around the hot weather in the Top End. I definitely noticed a difference, but it’s not always possible or practical for everyone to do this.

Early start before the sun
Early start before the sun – Nitmiluk National Park

2. Start Early To Beat The Heat

You’ve probably heard the age old saying, “beat the heat”. But this is actually a really important mentality to have when hiking in extreme heat. It’s best to stay out of the sun as much as possible, but more specifically it’s best to to stay out of the midday sun. The middle part of the day is when the sun and temperature will be warmest, so it’s a smart strategy to hike early to beat the heat.

While you might not usually be an early morning person (I’m certainly not!), it makes a huge difference if you can get up either at or before sunrise and hike in the early morning. This is generally the coolest time of the day. It pays to organise your gear the night before in preparation for a quick start.

However, an alternative is to hike at night. Some people prefer to hike a bit in the early morning, rest in the middle of the day and then hike at night. This might also work for you, depending on the trail you’re doing. Just ensure you pack a good headlamp!

Hot weather hiking clothing
Jatbula Trail

3. Cover Up And Stay Out Of The Sun

While it might seem counterintuitive, it’s best to cover your skin up. You might not feel like wearing lots of clothing in hot weather, but it does help keep your body temperature down by keeping the sun off your skin. Plus, it also reduces the need for re-applying sunscreen every hour.

However, it does matter what kind of clothing. Try to stick to wearing loose, breathable clothing to allow better airflow over the skin. You should also think about wearing lighter colours so as to reflect the sun, and you might even want to invest in ultraviolet protection factor or UPF rated clothing for extra sun protection.

It’s also a good idea to have a hat on (wide-brimmed is best in hot weather) and sunglasses to protect your senses and keep the sun off your head.

Refilling water
Nitmiluk National Park

4. Stay Hydrated

This is one of the most crucial tips for hiking in extreme heat. You must continue to replace any liquid lost through sweat and exertion. This is important for reducing the risk of becoming dehydrated and overheating. 

It’s generally recommended to consumer about 500ml of liquid per hour of activity. However, this is often raised up to a litre of liquid per hour in extremely hot conditions and/or during strenuous activity. But, this will differ depending on the person and the conditions, so it’s best to just sip on water every 20 minutes throughout your hike. This is why I find a hydration reservoir best for hot weather hiking, so your water is always accessible as you walk.

If you can, try to include some form of electrolytes in your hydration. I always keep some electrolyte tablets in my first aid kit, ready to dissolve in my drink bottle if I feel like I’m getting dehydrated or it’s heating up. This hands down certainly helped me survive the Southern Walks hike in Nitmiluk and get myself out safely.

It’s also not necessary to drink ice cold water either. While it might help you feel cooler, it won’t actually help lower your core body temperature, which is what you’re trying to achieve. So, in fact, room temperature water can be better and is often all you’ll have when out on the trail anyway!

Swimming on the Jatbula Trail
Swimming on the Jatbula Trail

5. Cool Your Body Temperature

After keeping hydrated, keeping your body temperature down is the next important part of hiking in hot weather. This is the part that causes most of the heat-related illnesses and it’s important to monitor how you’re feeling.

The best ways to keep your body temperature down are many of the things already mentioned: staying out of direct sun, drinking often, and covering up your skin. However, your body temperature may still rise while hiking.

Some other things to try, if you start to feel hot are: wet your buff to cool your neck down or your hat to cool your head, go for a swim in natural water holes (obviously a highlight of hiking in Nitmiluk National Park, but not always possible in other places), loosen your clothing and lie down in the shade.

6. Rest Often

While you might be in a hurry to get out of the hot sun, it’s also important to rest along the way. Your body is more likely to sweat and overheat the more you exert yourself. If you can slow down and take frequent breaks, it will allow your bodily processes to work itself out under less stress.

Rest breaks are also a good time to keep drinking water, sit in the shade, wet your hat or buff, and adjust your clothing.

Resting in the shade
Crystal Falls Camp – Jatbula Trail

7. Learn To Identify The Symptoms of Heat Exhaustion

If you read the first half of this blog post, then you would have read the symptoms for dehydration, heat exhaustion and heat stroke. If you make sure you’re familiar with these and the difference between them, you’ll be better equipped to manage yourself on the trail.

It’s definitely possible to hike in hot weather and prevent heat exhaustion, but it’s all about paying attention to your body and reacting to any symptoms you might feel. It’s also a good idea to check in with anyone else you’re hiking with and pay attention to any symptoms they might be showing as well.

8. Be Prepared to Call for Help, If Needed

If you suspect that you’re developing heat stroke, this is a medical emergency. Heat can kill and it’s important that you’re prepared to call for help, if needed. Once you’ve progressed past the point of heat exhaustion and succumbing to heat stroke, it can be too late to treat yourself on the trail.

For this reason, always carry a Personal Location Beacon or other emergency device while you’re hiking, so you can call for help from anywhere in the world.

Hiking the Jatbula Trail
Nitmiluk National Park

9. Keep Alert for Bushfire Danger Too

It goes without saying that in Australia, you should also be aware of bushfire risk on hot days. While some trails will automatically close on total fire ban days, there will always be some risk involved when hiking in hot weather.

Stay up to date with the national park alerts and rules regarding fire ban days and fire danger. You should also try to download the appropriate emergency alert app depending on which state you’re hiking in, such as Vic Emergency. This can keep you alert about any potential dangers in your area.

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