Heatstroke: Causes, Symptoms & Heat Safety Awareness

Heatstroke is the most severe form of heat-related illness and occurs when the body’s temperature regulation system becomes overwhelmed during extreme heat or strenuous activity. Body temperature rises rapidly and cooling mechanisms become less effective, which can affect multiple body systems.

Heatstroke is considered a medical emergency and requires prompt attention from trained responders and emergency medical services.

Relevance in Canadian Workplaces, Sports & Summer Heat

Heatstroke can affect outdoor workers, athletes, summer recreation groups, and individuals exposed to humid or stagnant environments. During Canadian heat waves, humidity reduces sweat evaporation and increases the risk of heat-related conditions.

Scenario 

During an early summer marathon, volunteers noted that one runner appeared confused and was slowing down dramatically. Event staff guided the runner into a shaded tent area where cooling supports and fluids were available until medical staff arrived.

Who Is at Higher Risk?

Heatstroke risk increases in:

• Infants and young children

• Older adults

• Individuals exercising or working in hot environments

• Athletes and labourers during peak heat

• Individuals with reduced heat tolerance or underlying health conditions

Symptoms of Heatstroke

Symptoms can develop gradually or suddenly, sometimes progressing from heat exhaustion. They may include:

• Elevated body temperature

• Hot, flushed, or dry skin (sweating may decrease)

• Headache or confusion

• Dizziness or disorientation

• Nausea or vomiting

• Rapid breathing or heart rate

• Muscle cramps or weakness

• In severe cases, reduced responsiveness or altered consciousness

Not every person experiences the same pattern of symptoms.

Causes & Contributing Factors

Heatstroke develops when the body cannot cool itself effectively. Contributing factors include:

• High ambient temperatures

• High humidity

• Intense physical exertion

• Limited hydration during prolonged heat exposure

• Wearing heavy or non-breathable clothing or equipment

• Lack of airflow or shade

• Rapid heat exposure without acclimatization

Management & First Aid Awareness

Public first aid awareness for heatstroke focuses on:

• Contacting emergency services promptly

• Stopping activity and moving to a shaded or cooler environment

• Cooling the body with shade, airflow, or cool cloths

• Offering small sips of fluids if the person is awake and able to drink

• Monitoring responsiveness while waiting for trained responders

Because heatstroke is a serious medical condition, medical assessment is important.

Prevention & Heat Safety Practices

Helpful strategies include:

• Hydrating before, during, and after heat exposure

• Scheduling breaks during hot and humid periods

• Wearing lightweight and breathable clothing

• Allowing time to acclimatize to heat at season start

• Adjusting work or training intensity during heat waves

• Ensuring children, pets, and vulnerable individuals are not left in parked vehicles

• Identifying indoor cooling spaces during extreme heat advisories

Canadian workplaces often use heat stress policies, education, and environmental monitoring to support worker safety.

FAQ

Is heatstroke the same as heat exhaustion?
No. Heatstroke represents a more advanced stage of heat illness where temperature regulation is impaired.

Can heatstroke occur without exercise?
Yes. Prolonged exposure to hot environments without adequate cooling or hydration can contribute.

Does humidity make heatstroke more likely?
Yes. Humidity reduces sweat evaporation, making it harder for the body to cool.

How quickly does heatstroke develop?
It varies. Some cases follow heat exhaustion, while others appear suddenly, especially during intense activity.

Educational Note

This article supports Canadian public and workplace education about heatstroke and heat safety. Individual heat tolerance, hydration needs, and medical considerations vary. Trained health professionals and emergency responders provide advanced care when needed.