Heat Exhaustion and Heat Stroke: What You Need to Know
- saidqabbaah
- Aug 10, 2025
- 4 min read
Updated: Jan 5
As temperatures climb across the world and heatwaves become a familiar part of our summers, extreme heat is moving into the spotlight for the very real risks it brings.
Among the most serious are heat exhaustion and heat stroke, conditions that can leave even healthy people vulnerable when their bodies struggle to cope with soaring temperatures.
The good news is that both can be prevented. But they can also escalate quickly if early signs are missed, which is why it is so important to understand what triggers them, how they tend to appear, and the simple steps you can take to stay safe when the heat becomes intense.
Understanding Heat-Related Illnesses
Your body is always working behind the scenes to keep your internal temperature close to 37°C. This automatic balancing act, called thermoregulation, helps you stay comfortable and healthy, even when the weather takes a turn.
When the temperature climbs, your body steps up its efforts by sending more blood to the skin and activating your sweat glands to reduce the heat and try to cool down. But long stretches in hot environments, especially if you are dehydrated, exerting yourself, or dealing with high humidity, can push these cooling systems beyond their limits. When they can no longer keep up, heat-related illnesses can start to develop.
"Heat stroke is a life-threatening condition that can strike suddenly.”
These problems usually unfold in stages. The first signs, like heat cramps, may seem easy to brush off, but without quick action, they can progress into more serious conditions such as heat exhaustion and, eventually, heat stroke. Heat stroke is a medical emergency that can rapidly affect vital organs and needs urgent treatment.
Heat Exhaustion: A Warning Sign
Heat exhaustion creeps in when your body sweats out more water and salt than it can afford to lose. It often strikes after long hours in the heat, especially when you’re pushing yourself physically, leaving your system struggling to keep up with the rising temperature.
Causes and risk factors
Several factors can raise your risk of heat exhaustion, including:
Hot, humid weather
Intense physical activity
Dehydration
Clothing that traps heat
Alcohol use
Medications such as diuretics or antihistamines
Young age or older age
Chronic conditions, including heart or kidney disease
Symptoms of heat exhaustion
Because the symptoms can be vague, it’s easy to mistake heat exhaustion for something else. Common signs include:
Heavy sweating
Weakness or fatigue
Dizziness or light-headedness
Headache
Nausea or vomiting
Muscle cramps
Cool, clammy skin
Fast heartbeat
Low blood pressure when standing
These symptoms often build up slowly, almost without you noticing at first. Taking a break somewhere cool, sipping plenty of fluids, and using simple cooling techniques can usually help your body recover gradually. But if you do not act quickly enough, heat exhaustion can tip over into heat stroke, which is far more dangerous.
Heat Stroke: A Medical Emergency
Heat stroke is a life-threatening condition that can strike suddenly and escalate very quickly. It happens when your body’s natural cooling system collapses, letting the core temperature soar above 40°C. At this stage, the heat starts to attack your organs and tissues directly, and every minute counts, making urgent medical attention absolutely critical.
Heat stroke typically appears in two forms:
Exertional heat stroke: More common in younger, active people performing strenuous exercise in hot conditions
Non-exertional (classic) heat stroke: More likely to affect older adults, people with chronic illnesses, or those in poorly ventilated spaces
Symptoms of heat stroke
A sudden spike in core body temperature signals the danger of heat stroke, often accompanied by warning signs that your body is crying out for relief:
Confusion or changes in mental state
Slurred speech
Seizures
Hot, dry skin (though sweating may still occur in some cases)
Rapid breathing
Loss of consciousness
Little or no sweating despite the heat
Heat stroke can lead to serious health consequences if not spotted and managed early. So, acting quickly can protect vital organs and, quite literally, save a life.
Diagnosis and Management
Recognising the warning signs of heat-related illness early can make all the difference. If someone shows symptoms of heat exhaustion, help them move to a cooler spot, offer water or a drink with electrolytes, and encourage them to rest. Simple measures like placing cool cloths or ice packs on the skin, or taking a brief cool shower, can also help bring their body temperature down.
If symptoms persist or worsen, it’s time to call for help immediately. While waiting for professionals to arrive, do your best to cool down the person while keeping them comfortable.
Healthcare professionals usually diagnose heat-related illness by looking at symptoms, recent heat exposure, and a physical exam. In more severe cases, blood tests may be needed to check how organs are functioning and to monitor electrolyte levels.
"Recognising the early signs of heat exhaustion or heat stroke could save a life.”
Staying Cool and Well
You can protect yourself from heat exhaustion and heat stroke with a few simple, practical steps:
Hydration
Stay hydrated by drinking water regularly, even if you don’t feel thirsty. Avoid alcohol and caffeine, which can worsen dehydration.
Appropriate clothing
Dress in lightweight, breathable, light coloured clothing.
Heat exposure
Limit outdoor activity during the hottest part of the day (usually 11 a.m. to 4 p.m.).
Cool down
Use cooling methods such as air conditioning, cool showers, or fans.
Be cautious
Give your body time to adapt if you’re working or exercising in the heat.
Be vigilant
Check in on vulnerable individuals, including older adults, infants, and those with chronic illnesses, during heatwaves.
Listen to your body
Stay alert to early symptoms so you can act before potential complications develop.
Staying Ahead of the Heat
As summer temperatures climb, the dangers of extreme heat rise with them. Recognising the early signs of heat exhaustion or heat stroke could be the difference between a quick recovery and a serious medical emergency. Staying one step ahead of the heat is a way to look after yourself and those you care about, helping everyone enjoy the sunshine safely.
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