Extreme heat

Different people respond differently to heat, and some people are at higher risk of experiencing health effects. Staying cool is especially important for the following groups of people:

• older adults, aged 60 years or older
• people who live alone
• people with pre-existing health conditions such as diabetes, heart disease or respiratory disease
• people with mental illness such as schizophrenia, depression, or anxiety
• people with substance use disorders, including alcohol
• people with limited mobility
• people who are marginally housed
• people who work in hot environments
• people who are pregnant
• infants and young children

Other people can be affected by heat too. Everyone responds differently, so listen to your body. 

Extreme heat events, also known as "heat waves," can cause a number of heat-related illnesses, and can lead to an increase in deaths. Heat-related illness is an umbrella term for conditions caused by heat, such as heat rash, sunburn, heat cramps, heat exhaustion, and, the most severe, heat stroke. 

Symptoms of heat exhaustion include:

• heavy sweating
• dizziness
• nausea or vomiting
• rapid breathing & heartbeat
• headache
• difficulty concentrating
• muscle cramps
• extreme thirst
• new skin rash
• dark urine & decreased urination 

Anyone with symptoms of heat exhaustion should move to a cool space, drink water, and apply cool water to large areas of the skin (cool bath, shower, or wet their clothes). Take these steps right away because heat exhaustion can quickly develop into heat stroke, which is a medical emergency. 

Symptoms of heat stroke include:

• high body temperature (39°C/ 102°F or higher)
• fainting or drowsiness
• confusion
• lack of coordination
• very hot and red skin

Heat stroke is a medical emergency. Seek medical attention immediately at an emergency room or urgent care centre. Call 911 if necessary. While waiting for help, cool the person right away by moving them to a cool space if possible, and apply cool water to large areas of the skin (cool bath, shower, or wet their clothes). 

Spending time in a cool space and drinking plenty of water is the best way to prevent heat-related illnesses.

• Seek cooler indoor and outdoor spaces (i.e. a local community center, library or mall.)
• Drink plenty of water and other liquids to stay hydrated, even if you do not feel thirsty.
• Use water to cool off by taking a cool shower or putting a part of your body in a cool bath.
• Wear a wet shirt or apply damp towels to your skin to cool down.
• Wear loose-fitting and light-coloured, breathable clothing.
• Limit activity, especially during the hottest hours of the day (generally 2 p.m. to 4 p.m. in B.C.)
• Close windows and pull indoor/outdoor shades/blinds around 10 a.m. to trap the cooler air inside and block the sun.
• Open windows and doors around 9-10 p.m. to let the cooler overnight air in (check the outdoor temperature is indeed lower than indoors.)
• Use one or more fans strategically to help move cooler air into the home overnight.
• Use exhaust fans, usually located in kitchens and bathrooms, to move warmer indoor air to the outside, and open windows to pull in cooler outdoor air overnight.
• Consider getting an air conditioner for your home; if you have air conditioning, be sure to turn it on.
• Monitor indoor temperatures for yourself and those you are checking on.
• Watch for symptoms of heat exhaustion and heat stroke. For heat-vulnerable people, the risk for heat-related illness may increase at indoor temperatures over 26°C (78 °F) and may significantly increase at indoor temperatures over 31 °C (88 °F).

Wildfire smoke can also cause health problems. During both wildfire smoke and heat events, consider also filtering your air using HEPA air cleaners. Find out more about wildfire smoke.

Check-in on your neighbours, friends and family often to ensure they are able to stay cool and have a plan in place. This can save lives. During previous heat events, a large proportion of the people who died were at home and socially isolated. 

In response to the 2021 heat dome, multiple health sector partners and Environment and Climate Change Canada (ECCC) have developed a BC Heat Alert and Response System (BC HARS) for the summer of 2022. This two level alert system lays out the criteria that ECCC will use to issue a Heat Warning (Level 1) or an Extreme Heat Emergency alert (Level 2), the appropriate public health messaging for both types of alerts, and the recommended actions for health sector and other partners. The province will continue to refine and improve the BC HARS in the years ahead.

Read more about the BC HARS on the BCCDC website.

Alerts

Heat Warning (Level 1)
Threat: Daytime and overnight temperatures are higher than seasonal norms and holding steady
Action: Take the usual steps to stay cool. 

Extreme Heat Emergency (Level 2)
Threat: Daytime and overnight temperatures are higher than seasonal norms and getting hotter every day. 
Action: Activate your emergency plan. 

Since summer 2021, the City of Vancouver, Vancouver Coastal Health and BC Centre for Disease Control have partnered to conduct a survey of self-reported temperatures. This information helps us better understand the relationship between indoor and outdoor temperatures and building characteristics across our communities. The goal of this work is to help inform recommendations for achieving safe cool temperatures inside existing buildings and help prevent heat illness.

Read the results of the 2021 Vancouver Indoor Air Temperature Survey.
Results of the 2022 survey will be released soon.
To participate in the survey this year (2023), please visit this link.

Following the 2021 BC heat dome, the VCH Public Health Surveillance Unit studied data on emergency room visits in collaboration with VCH and Providence Health Care Emergency Medicine programs. Several key findings were identified:

The extreme heat event that affected much of British Columbia in 2021 resulted in a substantial increase in Emergency Department visits related to heat-related illness in VCH hospitals.

Rates of heat-related Emergency Department visits varied substantially by area of residence. Among the urban neighbourhoods in the VCH region, a higher rate of heat-related ED visits was observed among residents in the Downtown Eastside, Kensington, Victoria-Fraserview, North Vancouver City-East/West, and North Vancouver District Municipality –Central.

Among age groups, the highest rate of heat-related ED visits was among those aged greater than 80 years. Slightly more than half of heat-related ED visits and over 90% of hospitalizations among these visits were among those aged 65 years or older.

Comprehensive heat event preparedness is essential to minimize future health impacts, as the risk of extreme heat events in the context of a warming climate continues to evolve.

Read the full report: 2021 BC Heat Dome VCH ER Visits