How to Recognise Dehydration Outdoors

How to Recognise Dehydration

Dehydration happens when the body loses more fluid than it takes in.

It’s something that outdoor groups should take seriously.

Walking, camping, hiking, climbing and other activities can all increase the amount of fluid a person loses through:

• Sweating
• Breathing
• Urination
• Vomiting
• Diarrhoea

Warm weather can make the problem worse, but dehydration isn’t only a hot-weather problem.

You can become dehydrated during a long hike in cool or cold conditions too.

The challenge is recognising it early.

What Does Dehydration Feel Like?

Early dehydration can be surprisingly easy to overlook.

Someone might simply feel:

• Thirsty
• Tired
• Headachy
• Weak
• Less energetic than usual

They might not immediately realise that they’re becoming dehydrated.

As dehydration becomes more significant, symptoms can become more obvious.

Common Signs of Dehydration

Look out for:

💧 Thirst

Thirst is an obvious warning sign, although you shouldn’t wait until someone is extremely thirsty before offering fluids.

🚽 Darker urine

Urine that is darker than usual can be a sign that someone needs more fluid.

🚽 Urinating less often

A person who hasn’t needed to urinate for an unusually long time may be becoming dehydrated.

😴 Tiredness

They may become unusually tired or lack their normal energy.

🤕 Headache

Headaches can occur with dehydration.

😵 Dizziness

Someone may feel dizzy or light-headed, particularly when standing up.

👄 Dry mouth

A dry or sticky mouth can be another sign.

💪 Weakness

They may struggle with activities that would normally be easy.

🧭 OUTDOOR LEADER TIP

Don’t only ask:

“Are you thirsty?”

Ask:

“When did you last have a drink?”

“How are you feeling?”

“When did you last go to the toilet?”

Small changes in behaviour can sometimes be easier to spot than someone simply saying they’re thirsty.

More Serious Dehydration

As dehydration becomes more severe, symptoms can include:

• Significant dizziness
• Very little urine
• Very dark urine
• Extreme weakness
• Confusion
• Unusual drowsiness
• Rapid heartbeat
• Rapid breathing
• Fainting or collapse

These symptoms should be taken seriously.

Someone who is confused, very drowsy, collapsed or unable to drink needs urgent medical assessment.

Dehydration in Children

Children can become dehydrated relatively quickly, particularly when they are:

• Very active
• Hot
• Vomiting
• Experiencing diarrhoea
• Not drinking normally

They may not always recognise or communicate thirst.

Look for changes such as:

• Unusual tiredness
• Dry mouth
• Reduced urination
• Dark urine
• Dizziness
• Irritability
• Lack of normal energy

If you’re concerned about a child’s condition, seek appropriate medical advice.

What Should You Do If Someone Is Dehydrated?

If someone appears mildly dehydrated and is otherwise well:

1. Stop or reduce the activity

Don’t expect someone who is becoming dehydrated to simply push through it.

Move them somewhere comfortable.

2. Provide fluids

Give them suitable drinking water or another appropriate fluid.

Encourage them to drink.

3. Rest

Allow them time to recover rather than immediately returning to strenuous activity.

4. Consider the environment

If it’s hot, move them somewhere cooler and shaded.

If they’re cold, make sure they’re appropriately protected from the cold.

5. Monitor them

Keep an eye on their condition.

If they don’t improve or symptoms become more serious, seek medical help.

💧 DON’T WAIT UNTIL THE END OF THE HIKE

One of the easiest ways to reduce dehydration risk is to make drinking part of the activity.

Small, regular drinks are generally more practical than suddenly drinking a huge amount after several hours without fluids.

What Should They Drink?

For most ordinary outdoor activities, water is the main drink you need.

For longer or particularly strenuous activities, appropriate drinks containing electrolytes may sometimes be useful, especially where substantial sweating has occurred.

However, don’t assume that energy drinks or sugary drinks are necessary simply because you’re hiking.

The important thing is maintaining adequate fluid intake.

Don’t Overdrink Either

There’s an important balance.

Drinking enormous quantities of plain water in a short period can also be dangerous because it can dilute the sodium concentration in the blood.

This is known as hyponatraemia.

For normal Scout activities, the practical lesson isn’t to calculate complicated fluid formulas.

It’s simply:

Drink regularly according to your needs, don’t deliberately avoid drinking, and don’t force yourself to consume excessive amounts of water.

Dehydration and Heat

Dehydration can occur alongside heat-related illness.

If someone is outdoors in hot weather and becomes:

• Very weak
• Dizzy
• Headachy
• Nauseous
• Confused
• Extremely hot
• Unusually sleepy

don’t assume it’s simply dehydration.

They may be developing heat exhaustion or heatstroke.

Heatstroke can be life-threatening and requires urgent action.

☀️ HEATSTROKE WARNING

Confusion, altered behaviour, collapse or a very high body temperature in someone exposed to heat should be treated as an emergency.

Don’t simply give them water and send them back into the activity.

Dehydration During Hiking

Hiking can make dehydration particularly difficult to recognise.

You’re concentrating on:

• Navigation
• Terrain
• Weather
• Keeping up with the group
• Your backpack
• Reaching the destination

It’s easy to forget about drinking.

That’s why hydration should be considered during route planning, not only once someone becomes thirsty.

Before setting off, consider:

How long are we going to be out?

What’s the weather forecast?

How much water is available?

Can we refill safely?

How much water does everyone need to carry?

Dehydration During Cold Weather

It might seem strange to talk about dehydration when it’s cold.

But you can still lose fluid.

Cold, dry air increases fluid loss through breathing, while physical activity can cause sweating even when the temperature is low.

People may also drink less because they don’t feel hot.

This means dehydration can occur during:

• Winter hiking
• Camping
• Mountain activities
• Skiing and snow activities
• Long-distance walking

Don’t assume cold weather means hydration isn’t important.

Dehydration and Survival Situations

In a survival situation, water becomes a priority.

However, don’t make the mistake of thinking:

“I’m thirsty, so I’ll drink anything.”

Unknown water sources can contain harmful microorganisms or other contaminants.

Instead, think about:

1. Finding the safest available source
2. Treating water appropriately
3. Conserving energy
4. Staying sheltered
5. Avoiding unnecessary fluid loss
6. Getting help

This is where water safety and survival skills overlap.

Preventing Dehydration Outdoors

Prevention is much easier than dealing with significant dehydration.

Carry enough water

Don’t assume you’ll find another source.

Start hydrated

Don’t begin a long hike already short of fluids.

Drink regularly

Make drinking part of your routine.

Consider the weather

Hot weather generally increases fluid requirements.

Protect yourself from excessive heat

Use shade, appropriate clothing and rest periods.

Plan your route

Know where reliable drinking water is available.

Monitor the group

Don’t only monitor the person who looks tired.

🎒 PACKING TIP

Water should be one of the first things you think about when preparing for an outdoor activity.

Food is important, but on a hot or strenuous day, inadequate water can become a problem much sooner.

How Much Water Should You Carry?

There isn’t one universal amount that works for every person and every activity.

Water requirements depend on factors including:

• Temperature
• Humidity
• Activity level
• Duration
• Individual needs
• Clothing
• Terrain
• Availability of safe refill points

A short woodland walk in cool weather is very different from a full day of hiking in hot conditions.

Plan accordingly.

A Simple Dehydration Check

For Scouts, you can teach a simple STOP routine:

S — Stop

If you’re feeling unwell, don’t simply keep walking.

T — Tell someone

Let a leader, instructor or companion know.

O — Observe

Think about thirst, urine, dizziness, headache, tiredness and how you’re feeling.

P — Protect yourself

Drink appropriately, rest and get somewhere comfortable.

This isn’t a medical diagnostic system, but it’s a useful reminder that speaking up early is important.

Common Mistakes

❌ Waiting until you’re extremely thirsty

Make drinking part of the activity.

❌ Ignoring headaches and dizziness

These can be warning signs.

❌ Assuming cold weather means you can’t dehydrate

You can.

❌ Pushing through because you’re almost at the destination

Your health matters more than reaching the end of the route.

❌ Drinking from an unsafe water source

Water should be treated appropriately.

❌ Assuming every hot-weather problem is dehydration

Heat exhaustion and heatstroke need to be considered.

Teaching Scouts About Dehydration

This is an easy subject to incorporate into a hike.

Before setting off, ask:

“How will you know if you’re becoming dehydrated?”

Then ask:

“What will you do?”

Finally:

“Who should you tell?”

The important lesson is that Scouts should tell someone as soon as they start feeling unwell.

They shouldn’t feel embarrassed about needing a drink or a rest.

🏕️ FOR SCOUT LEADERS

Build hydration into the activity rather than waiting for someone to ask.

During breaks, give everyone an opportunity to drink, particularly during warm weather or strenuous activities.

Also make sure leaders know where the group’s water supplies are and what the plan is if someone becomes unwell.

Dehydration vs Heatstroke

These conditions can overlap, but they’re not the same thing.

If someone is showing signs of heatstroke, don’t treat it as ordinary dehydration.

Get emergency medical help and begin appropriate cooling measures.

Final Thoughts

Dehydration is one of those outdoor problems that’s much easier to prevent than to deal with once it becomes severe.

Learn to recognise the early signs:

Thirst.

Dark urine.

Tiredness.

Headache.

Dizziness.

Dry mouth.

Reduced urination.

If someone is becoming unwell, stop the activity, provide appropriate fluids, allow them to rest and monitor them.

And remember that serious dehydration, confusion, collapse or suspected heatstroke requires urgent medical attention.

💧 THE BIG IDEA

Don’t wait until dehydration becomes obvious.

Drink appropriately, watch for early warning signs and tell someone as soon as you start feeling unwell.