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Extreme Heat

Many areas in Ontario have experienced unusual and prolonged periods of extreme heat within the last few years. Heat-related deaths and illness are preventable, yet people die due to extreme heat every year. Anyone can suffer heat-related illness when their bodies are unable to compensate and properly cool. It’s important to be aware of who is at greatest risk and what actions can be taken to prevent a heat-related illness or death.

Are You at Risk?

During a heat wave, everyone is at risk, but some groups are more vulnerable than others. They include :

Infants (under 1 year)
People 65 years of age or older
People with chronic medical conditions (heart disease, respiratory conditions, diabetes, etc)
People on certain types of medications ( for high blood pressure, depression, insomnia, etc)
Homeless people
People with limited mobility
People with mental impairment
People who exercise vigorously outdoors (play sports, cyclists, gardeners)
Outdoor workers (depending upon length or time and exertion levels)^†
People who work in places where heat is emitted through industrial processes (e.g., foundries, bakeries, dry cleaners) ^†

^† Please see the Ministry of Labour’s Website for further advice

Health Risks of Extreme Heat : Know When to Get Help

Adverse health effects can occur as a direct result of exposure to excessive heat:

Heat cramps : symptoms/signs include painful muscular cramps, usually in the legs or abdomen
Heat exhaustion : symptoms/signs include heavy sweating, weakness, dizziness, nausea, vomiting, fainting.
Heat stroke : symptoms/signs include headache, dizziness, confusion or other altered mental state, fainting. Skin may be hot and dry, or the individual may be sweating due to high body temperature. This is a medical emergency that can prove fatal!

Increases in other health problems can also be seen, especially for those with other chronic medical conditions such as heart conditions.

Consult a healthcare provider or call Telehealth Ontario (1-866-797-0000 or TTY at 1-877-797-0007) if you experience any of the above symptoms.

Things You Can Do to Protect Yourself

Check the weather network for information regarding weather and humidex reports.
Check the Ministry of the Environment for information regarding smog alerts.
Wear light, loose fitting clothes.
Drink plenty of water or natural fruit juices.
Avoid beverages such as alcohol, coffee, tea or cola.
Eat light, cool foods, and try to avoid using the oven or other hot appliances.
Stay in air conditioned rooms, either at home, at a friend’s place, or in public spaces such as malls, libraries, community centres or specially designated facilities.
If you do not have air conditioning at home, open windows slightly but keep blinds closed during the day on the sunny side of your home.
Keep indoor lights low or turned off.
Take cool baths or showers periodically to cool down.
If outdoors, stay in the shade and avoid strenuous physical activities. Wear sun block and a hat.
Check up on friends, family and/or neighbours regularly who may be at high risk during a heat event.
Do not leave people or pets in parked vehicles as they can get very hot!

Useful Heat-Related Links :

Ontario Public Health Unit Websites:

Document download

English
Extreme Heat
3 pages | 82 kb | PDF format

French
Extreme Heat
3 pages | 84 kb | PDF format

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For More Information

Call ServiceOntario, Infoline at 1-866-532-3161
(Toll-free in Ontario only)
TTY 1-800-387-5559. In Toronto, TTY 416-327-4282
Hours of operation : 8:30am - 5:00pm

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