Extreme Heat

Heat exhaustion occurs when the body loses large amounts of water and salt through sweat. This can happen during hot temperatures when a person does not drink enough liquids. Heat exhaustion can result in heat stroke if left untreated.

Symptoms:

• Dizziness
• Headache
• Nausea or vomiting
• Weak pulse
• Heavy sweating
• Pale skin
• Weakness/exhaustion
• Muscle cramps

Treatment:

• Move the person to a cooler location
• Encourage the person to cool down by sponging with cool (not cold) water, swimming or taking a shower or bath
• Provide sips of water

Heat stroke occurs when the body's temperature rises rapidly (to 40°C/104°F or above) and the body is unable to cool down. Heat stroke can cause death or permanent disability if emergency treatment is not provided.

Symptoms:

• Dizziness
• Headache
• Nausea or vomiting
• Strong pulse
• Red, hot and dry skin (no sweating)
• Confusion
• Loss of consciousness

Treatment:

• Dial 911, this is a medical emergency
• While waiting for medical assistance, help the person to cool down by sponging with cool (not cold) water
• Do not give the person any fluids as this may cause them to vomit or choke

Extreme heat affects everyone; however, some people are more at risk than others, including:

• Infants and children
• Seniors
• People with chronic diseases or medical conditions, such as heart disease or diabetes
• People taking medication for high blood pressure, depression or insomnia
• People who exercise vigorously or work outdoors
• People who are isolated or have limited mobility
• People experiencing homelessness
• People who are overweight
• People with mental illness, dementia or addiction

Check regularly on family, friends or neighbours during hot and humid conditions. Not sure what to look for when it comes to heat-related illness? Use this tool to help you assess your loved ones and how they are faring in the heat.

Urban Heat Island Profile

Source: Sky Space Green Roofs, Toronto (2019)

The way that communities are built can impact how warm they get, especially during the summer months. For example, some parts of York Region are hotter than those areas that are less urbanized. This is called the urban heat island effect. Higher temperatures in these communities may increase risk of heat-related illnesses which may have serious consequences.

Here are some of the characteristics of a community more likely to have higher temperatures:

• A lot of asphalt, as it absorbs and releases heat from the sun’s radiation
• Lack of trees and green space, which typically help decrease temperatures
• High-rise buildings built close together that block wind and trap radiation
• Heavy traffic, as car engines release extra heat into the environment

Does this sound like your community? If so, be prepared and stay safe during extreme heat by following the tips in Beat the Heat.

During extreme heat, keep cool and avoid added stress on your body.

Plan for Summer Heat

• Check local weather forecasts for the temperature, humidex and UV index
• Check Environment Canada for heat warnings
• Check regularly on family, friends or neighbours during hot and humid conditions. Not sure what to look for when it comes to heat-related illness? Use this tool to help you assess your loved ones and how they are faring in the heat.
• If you are taking medication, check with your doctor or pharmacist regarding possible side effects during extreme heat
• Stay hydrated! Drink plenty of cool liquids, especially water, before feeling thirsty
• Avoid drinks containing alcohol or caffeine
• Do not leave people or pets unattended in a car

Did you know? Warmer temperatures speed up the process of smog formation. Check the Air Quality Health Index daily to learn how to protect your health from outdoor air pollution. 

Stay Cool Outdoors

• Schedule outdoor physical activities in the morning and evening hours when it is cooler
• Reduce activity and rest often in shaded areas
• Wear lightweight, light-coloured, loose-fitting clothing made of breathable fabric
• Reduce sun exposure by wearing a wide-brimmed, breathable hat or use an umbrella
• Wear sunglasses with UV protection and sunscreen SPF 30 or higher

Stay Cool Indoors

• Stay in cool, well-ventilated areas
• Fans are only effective when circulating cooler air - Open a window or door if using a fan to bring in cooler air
• Close blinds and curtains to reduce the heat coming into your home
• Take a cool shower or bath, or wet your hands, face and the back of your neck
• Open windows at night if the outdoor air is cooler
• Prepare meals that don’t need to be cooked in the oven

For more information on where you can stay cool in your area, use the Cool Spaces Map or visit your local municipality's website. 

As part of the Extreme Heat Program, York Region Public Health notifies the public and its partners of hot and humid weather that can negatively affect health. The program was recently updated as part of a province-wide harmonization plan to ensure a more consistent approach for issuing heat warnings in Ontario.  Evidence-based triggers for York Region were developed that take into account both intensity and duration as described below:

In the event of a heat warning or extended heat warning, York Region Public Health will release public communications on our website and social media channels, advising the public to take extra precautions. York Region Public Health will also directly notify organizations and stakeholders whose clientele may be more vulnerable to extreme heat. The program runs annually from May 1 to September 30.