uOttawa researchers are helping Canada beat the rising heat

Posted on Wednesday, March 10, 2021

Man sitting in the world’s only calorimeter

Worker sitting in the world's only calorimeter, found in Glen Kenny's lab.

Temperatures are rising faster in Canada than in other regions of the world and the economic impacts of heat on human health are mounting. It is estimated that some provinces may face costs of more than $33 billion over the next 50 years for heat-related health care.

Portrait of researcher Glen Kenny

Dr. Glen P. Kenny is a Full Professor of Physiology and holds a University Research Chair in Human Environmental Physiology.

A research program led by Glen Kenny at the Faculty of Health Sciences and Carolyn Tateishi at Health Canada brings together global experts who will assess the factors that affect an individual’s physiological tolerance to heat.

This collaboration is one of five uOttawa projects that will share $23 million from the Canada Foundation for Innovation’s 2020 Innovation Fund. The CFI funding will help upgrade the world’s only air calorimeter, housed at the University of Ottawa, which precisely measures heat dissipated by the human body. It also includes the installation of a transformable temperature-controlled chamber that will help measure the human response to heat under different living and working exposure scenarios.

We asked lead researcher Glen Kenny to explain the timeliness of his research and how this one-of-a-kind equipment will help his team develop strategies to protect workers and the general population from the harmful effects of heat.

Why does heat-related healthcare matter today?

Extreme heat is a ‘silent’ killer because it is not a visible threat. It causes some of the highest death tolls of any other natural weather hazard, dramatically increasing short-term mortality in vulnerable populations, including children, women, seniors, and individuals with chronic health conditions or a disability.

Coupled with an aging population and workforce, more frequent and intense periods of extreme heat mean that a growing number of vulnerable older adults are at an increased risk of heat-related health problems. In response to this threat to population health, we must better understand the impacts of heat stress so that we can help Canadians adapt to rising temperatures.

In what ways will extreme heat hurt the Canadian economy?

The effects of environmental heat stress on the body directly threatens workers’ ability to live healthy and productive lives. It is estimated that within the next decade, heat-related labour productivity losses may be 70 times more damaging to healthy, productive and disability-free life years, than those resulting by occupational heatstroke fatalities. Less productive workers mean less productive businesses, and a less productive economy. Estimates indicate that the economic cost of diminished productivity may reach a staggering US$2 trillion globally by the end of this decade.

While the economic impact to Canada remains unclear, with the projected increase in temperatures to be amongst the highest in the world from current levels, labour loss due to occupational heat stress may cause wealth inequalities for Canada’s industries. In the absence of an effective strategy to mitigate these effects, the economic and societal impacts to Canada will be unparalleled.

What is lacking in our current approach to mitigating heat-related health problems?

The reason this work is important and timely is because there is a lack of information available on the best strategies to protect the most vulnerable. Some of the information we have is based on recommendations developed following extreme heat events that claimed thousands of lives and many of the solutions have not been tested or validated.

Our on-going work has shown that some of these solutions are misguided and may in fact negatively impact the health and well-being of vulnerable individuals. For example, to protect people against heat stress in the home, Canada has recommended that the maximum indoor temperature for multi-unit residential buildings be set at 26°C. The World Health Organization also provides recommendations for maximal indoor temperatures, though their threshold is set considerably higher at 32°C.

Moreover, both guidelines offer a ‘one-size-fits-all’ solution, such that neither explicitly considers the thermoregulatory and cardiovascular insufficiencies that may reduce the range of tolerable indoor conditions for vulnerable populations.

It remains unclear what indoor temperature limits should be employed to protect the health and well-being of vulnerable adults during hot weather.  Our work will establish strong evidence-based data to establish these upper limits.

Using the calorimeter, what questions are you looking to answer?

Our ability to develop heat management solutions and strategies that will mitigate the effects of heat stress on the general public and workers, including the development of sophisticated technologies for managing and monitoring heat strain, will depend on our ability to identify precisely the level of heat stress that pose a danger to the health and well-being of individuals.

Consequently, the critical first step to create these innovative heat protection solutions is to identify an individual’s threshold — the environmental and exercise-induced heat loads that impair the body’s physiological capacity to dissipate heat. Heat loads may affect individuals in different ways, depending on a variety of factors, such as sex, age, chronic disease and race, their levels of hydration, fitness, acclimation, and other factors that are beyond an individual’s control, such as the duration of their heat exposure.

We will be measuring whole-body heat loss in our world’s only air calorimeter. This technology provides the only gold standard method to precisely measure the heat dissipated by the human body. The high-resolution calorimetry data can guide us in setting an international standard for when to enact heat protection measures. It will also be used to identify exposure thresholds, or potential high-risk environments and work demands for different population groups.

We can tailor these solutions to specific populations by testing and refining these for different communities (e.g., people living in large built-up urban areas and remote Northern and Indigenous communities) and workers in various industries, including mining, electric utilities, construction and agriculture.

What might these solutions look like?

Once our lab has identified high-risk conditions for different population groups, our data can help inform heat protection policies and guidelines to safeguard the health of Canadians.

Our research could help inform short-term strategies, such as heat warning systems, an emergency response plan, heat advisories and maximum indoor temperature standards. It could also inform long-term guidelines for heat adaptation strategies and help establish culturally-sensitive heat protection standards and procedures that are ecologically valid and tailored to population groups.

Our data could also help develop practical and economically feasible protection strategies for workers, especially the most vulnerable, which so far have not been investigated at the size and quality needed to draw robust conclusions and recommendations. By understanding the high-risk work demands and environments that pose a threat to worker health and safety, our program can determine exposure limits for work in the heat, defined by the worker’s age, sex, fitness, health status and so on, creating a heat-resilient workforce.

Furthermore, ventilation is the single most expensive item in a company’s operating expenditure after manpower. During hot weather, larger volumes of cooled air are required to keep workers safe.  Because of rising temperatures and an increase in the frequency and intensity of extreme heat events, ventilation could become the overriding factor in profitability and sustainability of many Canadian industries where mass cooling is employed, including mining, manufacturing and power generation plants. Using our direct calorimeter, we have the ability to define air cooling requirements for specific environments tailored to groups of workers. With this data, we can inform industry on cost-effective cooling requirements to safeguard worker health and safety and minimize disruptions in productivity.

Our work will also stimulate new commercialization opportunities and drive the development of next-generation technologies, such as physiological monitoring systems to track heat strain, and innovations in smart clothing, personal cooling systems and heat smart homes.

Finally, this research can help inform new building codes that will help reduce the risk of overheating in dwellings, especially in those with vulnerable occupants, and help create heat-resilient communities.

Back to top