The Dangers of Heat Exhaustion and Heat stroke

Updated: Aug 12

As temperatures around the world continue to rise and heatwaves become more common, the health risks associated with extreme heat are receiving increased attention. Among the most serious conditions linked to prolonged exposure are heat exhaustion and heat stroke.

Although both are preventable, they can lead to serious health complications if not managed properly, making it essential to understand their causes, symptoms and how to best avoid them.

The human body maintains a stable internal temperature, usually around 37°C, through a process called ‘thermoregulation’ which is the body's natural way of keeping temperature within a healthy range, even as outside conditions change.

When external temperatures rise, the body responds by sweating and increasing blood flow to the skin to overcome the heat. However, prolonged exposure to high temperatures, especially when combined with high humidity, dehydration, or physical exertion, can overwhelm the body’s ability to cool itself down, resulting in heat-related illnesses.

These conditions occur in stages, beginning with mild symptoms, such as heat cramps, and progressing to more serious forms, such as heat exhaustion and heat stroke. The latter can impair vital organ functions and may even require urgent medical attention.

Heat exhaustion is a condition that results from excessive loss of water and salt, usually through sweating. It typically occurs after continued exposure to high temperatures, particularly during physical activity.

Several factors can increase the likelihood of heat exhaustion, including:

Hot and humid weather

Intense physical activity

Dehydration

Wearing excessive or non-breathable clothing

Alcohol consumption

Certain medications, such as diuretics and antihistamines

Age (young children and older adults are more susceptible)

Chronic illnesses, such as heart or kidney disease

The signs and symptoms of heat exhaustion are generally quite vague and may resemble those of other conditions. Common features include:

Heavy sweating

Weakness or fatigue

Dizziness or light-headedness

Headache

Nausea or vomiting

Muscle cramps

Cool, moist skin

Fast heartbeat

Low blood pressure when standing

These symptoms often develop gradually and may improve with rest, hydration, and self-cooling. However, if not dealt with quickly or appropriately, heat exhaustion can progress to heat stroke.

Heat stroke is the most serious form of heat-related illness and is considered a medical emergency. It happens when the body’s temperature regulation fails, causing the core body temperature to rise above 40°C. Unlike heat exhaustion, heat stroke can cause direct damage to organs and tissues, and may be life-threatening if not treated quickly.

Heat stroke may develop in two main ways:

Exertional heat stroke: Normally affects younger, active individuals engaging in strenuous activity in hot conditions

Non-exertional (classic) heat stroke: More common in older adults, individuals with chronic illnesses, or those in poorly ventilated environments

While the risk factors are mostly the same as heat exhaustion, the signs and symptoms of a heat stroke tend to be different.

The defining feature of heat stroke is a significant rise in core body temperature. Other symptoms may include:

Confusion or altered mental status

Slurred speech

Seizures

Hot, dry skin (though some people may continue to sweat)

Rapid breathing

Loss of consciousness

Absence of sweating despite heat exposure

Heat stroke is a medical emergency that requires immediate treatment to avoid organ damage or even death.

Quickly recognising the symptoms is critical to managing heat-related illnesses. If heat exhaustion is suspected, the person should be moved to a cooler place, given water or fluids with electrolytes and encouraged to rest. Using cool cloths or taking a cool shower can also help bring the body temperature down.

If symptoms do not improve, or if they worsen, urgent medical evaluation becomes necessary. For heat stroke, emergency services should be contacted immediately. While waiting for help, efforts to cool the individual (such as ice packs, cool mist, or immersion in cool water) are recommended.

Healthcare professionals usually diagnose heat-related illnesses based on symptoms, history of heat exposure and physical examination. In severe cases, blood tests may be used to assess important parameters such as organ function and electrolyte levels.

Preventing heat exhaustion and heat stroke involves several practical steps:

-Staying hydrated by drinking water regularly, even if not thirsty, while avoiding alcohol and caffeine, which can contribute to dehydration

-Dressing appropriately by wearing lightweight, breathable and light-coloured clothing

-Limiting outdoor activity especially during the hottest parts of the day (usually between 11 a.m. and 4 p.m.)

-Using cooling methods by spending time in air-conditioned spaces, taking cool showers and using fans when appropriate

-Allowing the body time to adjust gradually over several days if working or exercising in a hot environment

-Monitoring vulnerable individuals by checking in on older adults, infants and those with chronic illnesses during heatwaves

-Being aware of the symptoms which can help prevent progression to a more serious illness

As heatwaves grow more intense, so do the health dangers they bring. Recognising the early signs of heat exhaustion and heat stroke could be the difference between a quick recovery and a life-threatening emergency. Staying one step ahead of the heat isn’t just smart, it could potentially save a life.

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