As temperatures continue to climb across Ontario, heat waves are becoming more frequent, more intense, and more dangerous. Whether you're working outdoors, enjoying a weekend at the beach, coaching a summer sports team, or simply running errands, prolonged exposure to extreme heat can quickly turn into a medical emergency.
The good news? Heat stroke is often preventable.
Understanding the warning signs of heat-related illness and taking simple precautions can help keep you, your family, and your coworkers safe all summer long.
What Is Heat Stroke?
Heat stroke is the most serious form of heat-related illness. It occurs when the body's internal temperature rises above 40°C (104°F), and it can no longer cool itself effectively.
Without immediate treatment, heat stroke can damage the brain, heart, kidneys, and muscles! It is a life-threatening emergency that requires immediate medical attention.
Who Is Most at Risk?
While anyone can develop heat stroke, some people are at greater risk during Ontario's summer heat waves, including:
- Outdoor workers
- Construction and landscaping crews
- Warehouse employees without adequate cooling
- Athletes and coaches
- Children and infants
- Older adults
- People with chronic medical conditions
- Individuals taking certain medications
- Pets left outdoors or in vehicles
Even healthy adults can experience heat stroke if they become dehydrated or overexert themselves in hot weather.
Heat Exhaustion vs. Heat Stroke
Recognizing the difference between heat exhaustion and heat stroke can save a life. If caught early, heat exhaustion can often be treated and reversed, often just by first aiders. However, heat stroke is a life-threatening medical emergency that needs immediate professional intervention.
Heat Exhaustion:
- Normal or slightly raised core temperature (37-39 °C or 98.6-102.2 °F)
- Clammy, sweaty skin that is flushed (red) immediately after exertion, and then turns a different colour than usual
- Dehydration or intense thirst
- Headache, nausea, vomiting, dizziness, anxiety or fainting
- Weakness or exhaustion
If treated promptly with rest, fluids, and cooling, heat exhaustion can often be reversed before it becomes more serious. Use this infographic to learn more about how you can help someone experiencing heat exhaustion.
Heat Stroke:
Heat stroke is an immediate medical emergency. Watch for:
- High core temperature, above 40°C (104°F)
- Hot, dry skin
- Skin that is a different colour from usual
- Severe headache
- Altered mental status (e.g., confusion)
- Irritable, bizarre, or aggressive behaviour
- Progressive loss of responsiveness
- Rapid, weak pulse that becomes irregular
- Rapid, shallow breathing
- Vision problems
- Seizures or coma
If someone shows signs of heat stroke:
- Call 911 immediately.
- Move them to a cool, shaded area.
- Remove excess clothing.
- Cool them quickly using cool water, wet towels, fans, or ice packs placed on the neck, armpits, and groin.
- Do not delay medical care.
To learn more about first aid for heat stroke, use this infographic.
10 Ways to Prevent Heat Stroke
1. Stay Hydrated
Drink water regularly! Even before you feel thirsty!
Avoid excessive alcohol and limit sugary or highly caffeinated drinks, as these can contribute to dehydration.
2. Dress for the Weather
Choose lightweight, light-coloured, loose-fitting clothing that allows sweat to evaporate.
Wear a wide-brimmed hat and sunglasses when outdoors for further protection.
3. Plan Outdoor Activities Wisely
Plan your outdoor activities according to the weather for the day. Try to schedule physically demanding work or exercise during the early morning or evening when temperatures are lower.
If you must be outside during the hottest part of the day, take frequent breaks in shaded or air-conditioned areas.
4. Never Leave Anyone in a Parked Vehicle
Temperatures inside a parked vehicle can rise dramatically within minutes, even with the windows cracked open!
Never leave children, older adults, or pets unattended in a vehicle!
5. Know Your Workplace Heat Safety Plan
Employers should provide:
- Drinking water
- Rest breaks
- Shade or cooling areas
- Training on heat-related illness
- Emergency response procedures
Workers should report symptoms early rather than trying to "push through."
6. Use Sunscreen
Did you know that getting a sunburn not only damages your skin and increases your risk of skin cancer, but it also reduces the body's ability to cool itself and increases the risk of heat-related illness?
Apply a broad-spectrum sunscreen with SPF 30 or higher and reapply as directed.
7. Acclimatize Gradually
Going on a nice summer vacation? When you're returning to outdoor work or exercise after time away, increase your activity gradually over several days to allow your body to adjust to the heat.
8. Check on Vulnerable Family Members and Neighbours
Older adults and people living alone may not recognize the signs of heat illness.
A quick phone call or visit to high-risk loved ones during a heat wave could make a significant difference.
9. Watch for Early Warning Signs
Headache, dizziness, excessive sweating, muscle cramps, and nausea are your body's warning signals.
Take them seriously and cool down before symptoms worsen.
10. Learn First Aid
Knowing how to recognize and respond to heat stroke can save a life before emergency services arrive.
First aid training can help you respond quickly and confidently during heat-related emergencies. Register for a first aid course here.
Heat Safety for Ontario Workers
Heat waves can create serious hazards in many industries, including construction, manufacturing, landscaping, agriculture, recreation, and event management.
Employers can help reduce heat-related injuries by:
- Encouraging frequent hydration
- Rotating physically demanding tasks
- Providing shaded rest areas
- Monitoring employees for signs of heat illness
- Training staff in first aid and emergency response
A proactive approach helps protect workers while also reducing lost time and workplace injuries.
Build a Summer First Aid Kit
A well-stocked first aid kit can help you respond to heat-related illnesses and other common summer injuries.
Consider including:
- Instant cold packs
- Bottled water or electrolyte packets
- Digital thermometer
- Gloves
- Gauze and bandages
- Antiseptic wipes
- Emergency blanket
- Sunscreen
- Insect bite relief
- Emergency contact information
Keep kits in your vehicle, workplace, cottage, or sports bag so they're always within reach! You can buy these additional supplies or a fully stocked first aid kit here.
Prevention Starts Before an Emergency
Heat stroke doesn't happen without warning! By staying hydrated, planning ahead, recognizing early symptoms, and knowing how to respond, you can significantly reduce the risk of serious heat-related illness.
Whether you're working outdoors, supervising children at the pool, coaching a sports team, or spending time with family, a few simple precautions can make all the difference.
At KMW Outreach, we're committed to helping individuals, families, and workplaces stay safe through high-quality first aid training, workplace safety education, and emergency preparedness resources.
This summer, don't wait for an emergency to learn what to do. Prevention starts long before someone needs first aid.
To learn more about first aid for heat stroke, use this infographic.
