Health and Wellness

A Quick Guide to Extreme Heat Vulnerability

You might not believe it considering the weather this summer, but intense heat can be a real health issue, even in Toronto. According to Health Canada, people can experience direct, immediate damage from heat, including heat stroke, exhaustion, fainting, cramps, rash, and edema; people with underlying conditions can also experience a worsening of other symptoms.

People at increased risk for heat related illness include:            

  • Older adults
  • Infants and young children
  • People with chronic illnesses, such as heart or respiratory conditions, people with limited Physical mobility, people with certain mental health illnesses, people on certain medications
  • People who work or exercise in the heat
  • Homeless people and low-income earners
  • People on the lower end of the socio-economic scale

Louis, Photo Courtesy of Bryan on Flickr

Louis, Photo Courtesy of Bryan on Flickr

In Toronto, heat-related injuries can be prevented. One of the best ways to prevent them is to recognize that different people are sensitive in different ways, and how best to respond to each sensitivity:


Infants and young children sweat less than adults and produce proportionately more body heat when moving, so care should be taken to avoid over-exertion. Sports should not be played outside in the hottest hours of the day, and care should be taken to spend as much time as possible indoors, preferably in places with air conditioning.

Note: Regular physical activity is as important as ever, but should not be encouraged in unhealthy conditions.


One of the biggest problems faced by the elderly is a lack of sensitivity to thirst, which can combine nastily with “differing perceptions of risk and vulnerabilities based on life experiences”. In other words, some elderly people may be unable to tell how much water they need, or if their bodies are getting too hot. Elderly people may also experience a reduced sweating ability, which eliminates an important sign of potential overheating. It may be helpful to calculate how much water to drink throughout the day before you go out, so you don’t have to rely on the senses at all.

Ill or Impaired

People who are physically or mentally ill or impaired may have to worry about interactions between their unique conditions, their medications, and the effects of extreme heat. For instance, certain antidepressants affect the body’s water retention functions, so more water must be consumed than normal to maintain the right levels. Talk to your pharmacist about the possible effects that extreme heat may have about medication, and speak to your doctor (or specialist, where relevant) if they haven’t already explained how the weather may affect the patient’s body. Some health care professionals might forget to mention this if you happen to meet with them in the cooler months, so be proactive and ask outright.

The information source of this article is the report “Adapting to Extreme Heat Events: Guidelines for Assessing Health Vulnerability” by Health Canada, circa 2011. As well as from the City of Toronto: Beat The Heat

Original article posted August 11, 2014 by Louis Train. Edited and reposted by Kohen McBride (July 2015)