How to Combat the Effects of a Heat Wave

Heat waves are becoming more common, with daily record temperatures occurring twice as often as record lows.

Heat waves are becoming more common, with daily record temperatures occurring twice as often as record lows (Center for Climate and Energy Solutions).  A recent study estimates that the yearly number of days over 37.7 degrees celsius will double and the number of days over 40.5 degrees celsius will triple when compared to the end of the 20th century (Center for Climate and Energy Solutions). 

What causes a heat wave?

“A heat wave is a hot weather phenomenon which is accompanied by the high temperature and high humidity that causes a prolonged period of abnormally hot weather. . . According to the World Meteorological Organization, the term ‘heat wave’ refers to the situation when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5 °C.” (Shakeel Anwar). It is caused by air that is trapped over one region, usually because of high-pressure systems,  and the sunlight warms it to abnormal temperatures (Energy Education).  

Extreme heat is one of the most dangerous natural hazards, but it rarely receives attention as the death toll and other complications are not immediately obvious (World Health Organization).  Did you know that more than 166,000 people have died because of extreme temperatures between 1998 and 2017?  (World Health Organization)

Where do heat waves occur?

While southern regions of Canada are more likely to suffer from heat waves, they can occur anywhere in Canada.  The most likely time of year occurs between the months of June and September (Canadian Red Cross). 

What are the Side Effects of Heat Waves?

Extreme heat can cause a variety of complications which pose a risk to people, ecosystems and the economy.  Four of the top 10 deadliest U.S. disasters since 1980 are heatwaves and they kill over 600 per year more than all other impacts combined, excluding hurricanes (Center for Climate and Energy Solutions).   Heat related illnesses include cardiovascular and respiratory challenges, kidney disease, heat exhaustion, heat stroke, a heat rash, cramps, amplification of pre-existing conditions (including cerebrovascular disease and diabetes) and can result in premature death and disability.  Heat waves can overload health and emergency services and strain water, energy and transportation services which can result in blackouts or power shortages.  They can also cause socioeconomic impacts due to reduced work capacity and labor productivity.  


Often the first noticeable symptoms include dizziness, lightheadedness, weakness, anxiety, intense thirst, maliase, unusual fatigue, and headaches.  

Those most at risk include:

  • Outdoor and manual workers;
  • Children;
  • Elderly;
  • Those who suffer from obesity;
  • Low-income households;
  • Pregnant women; and
  • Athletes


Preventing the effects of heat waves:

  • Keep your living space cool, ideally below 32 degrees celsius during the day and 24 degrees celsius at night;
  • Use night air to cool down your home;
  • Reduce the heat load inside your home.  One way to do this is to turn off artificial lighting and as as many electrical devices as possible;
  • Utilize shades, drapes, awnings or louvers on windows;
  • Hang wet towels to cool down the room air;
  • Use electric fans, but keep in mind that after 35 degrees celsius they may not prevent heat-related illnesses;
  • Keep out of the heat;
  • If you cannot keep your home cool spend at least 2-3 hours per day in a cool place such as an air conditioned building;
  • Avoid going outside during the hottest part of the day;
  • Avoid strenuous activity if possible;
  • Stay in the shade;
  • Take cool showers;
  • Wear light, loose-fighting clothing made of natural materials;
  • Wear a hat and sunglasses if going outside;
  • Use light bed linens and no cushions;
  • Avoid alcohol, caffeine and sugar;
  • Eat small meals and eat more often;
  • Do not leave children or pets in parked vehicles; and 

Staying aware and informed of weather conditions is essential to safeguard yourself and your family.  It can be easy to not recognize how dangerous heat can be.  Download the Alertable app today to receive severe weather alerts, including extreme heat.  

Learn how Toronto is handling a heat wave during the COVID-19 pandemic here:

What are other tips we could talk about? Leave a comment below and let us know.

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