Heat Exhaustion Symptoms in Adults and Children
Warm weather brings real risks for the people you support — particularly children, older adults, and anyone with an existing Health condition. Knowing how to recognise Heat Exhaustion early, and what to do about it, can make all the difference between a quick recovery and a trip to A&E.
This guide brings together everything our Trainers are asked most often. Whether it’s a baby, a child, an older relative, or a resident in your care, we’re here to help.
What Is Heat Exhaustion?
Heat exhaustion happens when the body gets too hot and struggles to cool itself down, usually after time in the heat, physical activity, or not drinking enough fluids. It’s the body’s early warning system — and the good news is that, unlike heat stroke, it can almost always be managed with simple first aid if you act quickly.
Left untreated, heat exhaustion can progress to heat stroke, which is a medical emergency. Understanding the difference is one of the most important things anyone working in health and social care can learn.
Heat Exhaustion vs Heat Stroke: What’s the Difference?
This is one of the questions we are asked most, so let’s make it simple:
Heat Exhaustion — the body is overheating but can still cool itself down. The person is sweating, may feel unwell, but is alert and responsive.
Heat Stroke — the body’s cooling system has failed. Body temperature rises above 40°C, the skin may become hot and dry rather than sweaty, and the person may become confused, drowsy, or unresponsive.
Heat Stroke is a Medical Emergency. If someone shows signs of heat stroke, call 999 immediately. Read more here.
Signs and Symptoms of Heat Exhaustion
The signs of Heat Exhaustion can appear gradually, so it helps to know what to look out for:
- Tiredness or weakness
- Dizziness or feeling faint
- Headache
- Nausea or vomiting
- Heavy sweating
- Cool, pale, or clammy skin
- Cramps in the arms, legs, or stomach
- A fast heartbeat or fast breathing
- Intense thirst
A note on diarrhoea: a number of people ask whether diarrhoea can be a symptom of Heat Exhaustion. It isn’t one of the classic signs, but nausea, vomiting, and stomach cramps are common — and dehydration from any cause, including diarrhoea, can make someone more vulnerable to Heat Exhaustion. If in doubt, treat it as a sign the body needs fluids and cooling, and monitor closely.
Signs of Heat Exhaustion in Babies, Toddlers, and Children
Babies and young children can’t always put how they feel into words, and their small bodies overheat far more quickly than an adult’s. That’s why it’s so important to recognise the signs early.
Look out for:
- Fewer wet nappies than usual, or dark urine
- Being unusually sleepy, floppy, or irritable
- Flushed, hot skin
- Rapid breathing
- Refusing food or drink, or being sick
- Crying without tears
- A sunken soft spot (fontanelle) in babies
If a baby or young child shows any of these signs, move them to a cool place, offer small, frequent sips of water, and remove excess clothing. Contact NHS 111 or your GP promptly, and seek emergency help if symptoms don’t improve within 30 minutes or if the child becomes drowsy or unresponsive.
Heat Exhaustion in Pregnancy
Pregnancy increases the body’s sensitivity to heat, so pregnant people can be at higher risk of Heat Exhaustion. The same core signs apply — dizziness, nausea, heavy sweating, and fatigue. It’s worth taking symptoms particularly seriously during pregnancy and seeking advice from a midwife or GP if they don’t settle quickly with rest, fluids, and cooling.
Can You Get Heat Exhaustion Indoors?
Yes. Heat exhaustion isn’t only a risk in direct sunshine. It can happen indoors too, especially in poorly ventilated rooms, conservatories, vehicles, or homes without air conditioning during a heatwave. This is an important point for anyone working in Residential or Home Care settings: checking indoor temperatures and airflow matters just as much as advising people to stay out of the midday sun.
How to Treat Heat Exhaustion at Home
Following NHS guidance, the aim is to cool the person down and rehydrate them as quickly as possible:
- Move them to a cool place — indoors, or into the shade.
- Remove any unnecessary clothing, such as a jumper or socks.
- Cool their skin — sponge or spray them with cool water, or apply cool, wet cloths to the neck, armpits, and groin. A fan can help too.
- Give them water to drink — small, frequent sips. Rehydration or electrolyte drinks can help replace lost salts and minerals, particularly after heavy sweating.
- Let them rest lying down with their legs slightly raised.
Most people start to feel better within 30 minutes of following these steps.
When to Seek Emergency Help
Call 999 or take the person to A&E if:
- Symptoms don’t improve within 30 minutes of cooling and rehydration
- The person becomes confused, drowsy, or unresponsive
- They have a fit or seizure
- Their temperature is very high and their skin feels hot but they’ve stopped sweating
- They’re not sweating despite feeling too hot
These are signs the condition may have progressed to heat Stroke, and it needs urgent Medical attention. Read our guide on what to do in a Medical emergency.
How Long Does Heat Exhaustion Last?
With prompt cooling and rehydration, most people recover within 30 minutes to a few hours. However, feeling drained or unwell for a day or two afterwards isn’t unusual, particularly in older adults, young children, or anyone who was already unwell. If symptoms persist beyond this, or keep returning, it’s worth seeking Medical advice.
Preventing Heat Exhaustion: Practical Tips for Carers
Prevention is always better than treatment. In any Care setting, small adjustments make a big difference during warm weather:
- Encourage regular fluids throughout the day, not just when someone feels thirsty
- Keep living spaces cool — close curtains, use fans, and ventilate rooms in the early morning or evening
- Choose loose, breathable clothing
- Plan outdoor activities for cooler parts of the day
- Check in more often on those most at risk — babies, older people, and anyone with a long-term health condition
- Keep an eye on Dehydration symptoms: dry mouth, dark urine, tiredness, and headaches are early warning signs
Frequently Asked Questions
What’s the difference between heat exhaustion and sunstroke?
Sunstroke is another term often used interchangeably with heat stroke. The more serious condition where the body can no longer cool itself. Heat Exhaustion is the earlier, more manageable stage.
Is Diarrhoea a sign of Heat Exhaustion?
It’s not one of the primary symptoms, but vomiting and stomach cramps are common, and dehydration from any source increases the risk of Heat Exhaustion.
Can heat exhaustion last for days?
Typically symptoms ease within hours of proper cooling and rehydration, though tiredness can linger for a day or two, especially in vulnerable individuals.
What are the first signs of Heat Exhaustion?
Early signs usually include tiredness, headache, dizziness, and heavy sweating — this is the best time to act, before symptoms progress.