Staying Healthy in Summer Heat and Smoke
Southern Alberta summers are sunny, dry and long-daylight, and some years bring days of wildfire smoke too. This page covers who is most at risk, telling heat exhaustion from heat stroke, what a heat warning means here, keeping cool without air conditioning, cars and kids, and reading the Air Quality Health Index when the smoke rolls in.
On this page
Who is most at risk
Anyone can get sick from heat, but Health Canada names these groups as most at risk:
The youngest and oldest
Infants and young children, who depend on others to keep them cool, and older adults, especially those living alone or taking medications that affect how the body cools.
Some health conditions
People with breathing difficulties, heart problems or psychiatric illnesses.
People working or active outside
Construction and road crews, farm workers, and anyone exercising hard in the heat.
What it means for you: on a hot day, check on older neighbours, friends and family, especially anyone who lives alone or is unwell. A quick call or visit to make sure they are cool and drinking water is one of the most useful things you can do.
General information only, not medical advice. In an emergency, call 911.
Heat exhaustion or heat stroke?
Heat illness usually starts as heat exhaustion. If the body keeps heating up, it can turn into heat stroke, which is a medical emergency.
| Heat exhaustion | Heat stroke: call 911 |
|---|---|
| Heavy sweating, extreme thirst, dark urine and peeing less, headache, dizziness or fainting, nausea or vomiting, muscle cramps, rapid breathing and heartbeat, skin rash. | High body temperature, confusion and poor coordination, dizziness or fainting, and skin that is hot and red, either dry or damp. |
| Do: move to a cool place right away and drink water. | Do: call 911, then cool the person while you wait. |
Heat stroke is a medical emergency. Health Canada says to call 911 immediately. Confusion is the big warning sign: someone who is hot and not making sense needs help now.
While you wait for help
- Move them somewhere cooler if you can: shade, a cool room or an air-conditioned car.
- Put cold water on large areas of skin. Soak their clothes, use wet towels or a hose.
- Fan them as much as you can. Moving air on wet skin carries heat away fast.
When a heat warning is issued
Environment Canada issues a heat warning when the heat is expected to last at least two days, with daytime highs reaching about 29 °C and overnight lows staying at 14 °C or warmer. The warm nights are what make it dangerous: homes never get a chance to cool down, and neither do the people in them.
When a warning is out:
- Drink water often, even before you feel thirsty.
- Move hard outdoor work and exercise to a cooler day, or to early morning.
- Spend the hottest part of the day somewhere cool.
- Check on people who are at higher risk.
Our Feels Like tool shows how hot it actually feels on the west side, using live readings from the station.
Keeping cool at home
- If you have air conditioning, make sure it works before the first hot spell, not during it.
- If you don’t, know where you can go to cool off for a few hours: an air-conditioned public building, a library, a mall, a swimming pool or a shady park.
- Keep the sun out during the day. Closed blinds and curtains on sunny windows keep a lot of heat out.
- Let the cool in at night. When the air outside is cooler than inside, open up and move it through the house.
- Cool yourself down. A cool shower or bath, or a damp cloth on the skin, brings body temperature down.
Cars, kids and pets
Never leave children or pets alone in a parked vehicle, not even for a minute, and not even with a window cracked. A closed car in the sun heats up far faster than the air outside.
A few habits that help: put your phone, bag or wallet in the back seat so you always look there before you lock up, and keep the car locked at home so kids can’t climb in to play.
Wildfire smoke and the AQHI
When fires are burning in B.C., the mountains or the north, smoke can sit over Lethbridge for days. The Air Quality Health Index (AQHI) rates the air from 1 to 10+. It is part of the Environment Canada forecast and is the easiest way to decide what to do.
| AQHI | Most people | At-risk people |
|---|---|---|
| 1 to 3 Low | Normal outdoor activities. | Normal outdoor activities. |
| 4 to 6 Moderate | Carry on, but watch for coughing or throat irritation. | Consider cutting back or rescheduling hard outdoor activity if you have symptoms. |
| 7 to 10 High | Consider cutting back or rescheduling hard outdoor activity if you have symptoms. | Cut back or reschedule hard outdoor activity. |
| 10+ Very high | Cut back or reschedule hard outdoor activity, especially with symptoms. | Avoid hard outdoor activity. |
At-risk people include children, adults over 65, pregnant people, and anyone with heart or lung conditions such as asthma or COPD.
On smoky days
- Stay inside with the windows closed, and exercise indoors or wait until the air clears.
- Clean the air in one room. A portable air cleaner with a high-efficiency filter makes a big difference in a bedroom.
- If you have to be outside, a well-fitted respirator such as an N95 filters the fine particles. It won’t filter the smoke gases.
- Go back inside if you notice symptoms such as stinging eyes, a scratchy throat, headache or wheezing.
Heat and smoke together: if keeping the windows shut makes the house too hot, go somewhere cool and clean-aired for part of the day rather than sitting in the heat.
Working and playing outside
- Save hard jobs like mowing, roofing and long rides for cooler days or early mornings.
- Take water with you and drink it, and take breaks in the shade.
- Our dry prairie air dries sweat quickly, so you can lose a lot of water without feeling soaked. Pay attention to thirst and dark urine.
- Sun protection matters too. See Sun, wind and the elements for UV, hats and sunscreen.
More on summer safety: yard safety, camping weather and safety and first aid.
Your body has its own air conditioner: sweat. When sweat dries on your skin, it carries heat away. But it only works if you drink enough water to keep making sweat. On a hot day, drink water before you feel thirsty, play in the shade, and tell a grown-up right away if you feel dizzy, sick to your stomach or get a headache.
Sources
- Health Canada, Fact sheet: Staying healthy in the heat (who is at risk, heat exhaustion and heat stroke signs, first aid, prevention): canada.ca
- Environment and Climate Change Canada, About the Air Quality Health Index (categories and health messages): canada.ca
- Global News, Alberta heat warnings, July 2022 (Environment Canada meteorologist on heat warning criteria: at least two days, highs of 29 °C, lows of 14 °C or higher): globalnews.ca
- CBC News, How you can protect your health from wildfire smoke, 2023 (Health Canada advice on staying indoors, air cleaners and respirators): cbc.ca