Learning Module | Health THREATS
Chapter Three
3. EXTREME WEATHER
HEAT WAVES
Introduction
The continual warming of our climate has been well documented, with relevance in Western Canada, where up to a 3-degree Celsius increase in temperature above pre-industrial levels has been observed. [1,2] The continual warming of our climate has been well documented, and Canadian temperatures have increased at approximately twice that of the global rate, and 9 of the 10 warmest years have occurred during the last 25 years. [3]
In western Canada, June 2021 was witness to a historic heat wave record, where a temperature of 49.6 degrees Celsius was observed in Lytton, British Columbia. The extreme heat was responsible for 619 deaths in British Columbia. [4]
Our warming climate will result in increased intensity, frequency, and severity of heat waves and result in negative health impacts such as heat stress, heat stroke, and exacerbation of conditions such as cardiovascular and renal disease. [5,6,7]
Effect of Heat on Health
Pathophysiology of Heat Response.
Normally, in response to increased core and surface temperature, your body attempts to dissipate this heat through vasodilation, increased cardiac output, and diaphoresis. [8,9]
In cases of extreme heat and heatwaves, these compensatory mechanisms can fail, causing a cascade of events leading to a systemic inflammatory response, and resulting heat stroke. Heatstroke is the most severe form of heat illness and is a health emergency, seen clinically as a core temperature of 39-40 degrees Celsius, central nervous system dysfunction, and multi-organ failure. [10]
A comprehensive overview of heatstroke can be found here.
Image retrieved from https://www-nejm-org.ezproxy.library.ubc.ca/doi/full/10.1056/NEJMra1810762
Vulnerable Populations
Understanding which populations are more susceptible to the effects of heat is imperative in preventing negative health outcomes.
This is a non-exhaustive list, but some other examples include:
The elderly [11,12]
Urban populations [13,14]
Those with chronic illnesses [13,15,16]
Homeless populations [17]
Women- to learn more about how heat waves disproportionally impact women, click here.
Image retrieved from https://www-nejm-org.ezproxy.library.ubc.ca/doi/full/10.1056/NEJMra1810762
Take Action
Stay alert and keep your patients informed.
The treatment for heat stroke is rapid cooling, with its prevention being far superior than any cure. [18] As a future physician you have the opportunity to identify these vulnerable populations, and initiate conversation about the increasing risk of heat waves during the summer months. Some heat stroke prevention strategies include:
Monitoring those at risk (such as elderly patients living alone) by encouraging community check-ins with these individuals during heat waves.
Teach vulnerable patients to be aware of heat wave warnings, and to ensure access to water, and cooling facilities.
Prevent heat related illness by avoiding outdoor activity between 10am and 4pm, taking a cool bath or shower, and ensuring hydration. [19]
Encourage active living which among its many other benefits, is also shown to improve heat tolerance. [20]
Resources for Patient Education:
Healthlink BC - Information on heat related illness for patients.
Extreme Heat: Heat Waves - Safety tips in extreme heat.
Extreme Heat Information Sheet - helpful patient education infographic.
Invest in long term outcomes.
While education plays a key role in patient safety, ultimately adaptations will need to be made to accommodate our rapidly changing climate. Infrastructure changes, such as decreasing urban heat island effects through tree planting, increased water fountain installations, and use of appropriate building materials to reduce heat trapping in buildings and pavement are all tactics currently in Surrey’s Climate Adaptation Strategy. [21]
As physicians we can also play a role by getting involved in policy to advocate for our patient’s health, and for further climate adaptive infrastructure developments. For example, family physicians can get involved with school boards, recreation programs, and sports medicine advisory committees to discuss and advocate for heat safety improvements. [22]
Continue learning.
Canadian Family Physician - Strategies for prevention and treatment of heat-induced illness.
Municipal Heat Response Planning in British Columbia - comprehensive overview of heat waves and recommendations for heat response planning in BC.
Review of Heat-Related Deaths in BC in June 2021: Highlighting opportunities for patient education during physician contact.
In June 2021, 619 heat-related deaths occurred in British Columbia. 67% of these patients were age 70 or older, and more than 80% had 3 or more chronic diseases.
Upon review, it was found that over 60% of these individuals had seen a medical professional the month prior to their passing, with 62% having 12 or more visits with health professionals within 12 months before their death.
This highlights the opportunity for physician identification of patients at high risk of being impacted by heat waves and providing education.
Heat-related deaths occurred more frequently in:
Persons aged 70 or older
Persons with chronic disease (including schizophrenia, substance use disorder, epilepsy, COPD, depression, asthma, diabetes, mood, and anxiety disorder)
Those with 3 or more chronic diseases, with 69% having chronic illnesses that could impact mobility (such as heart failure, arthritis, Parkinson’s disease) and 64% having chronic illnesses that could impact cognition (including mood and anxiety disorders, dementia, schizophrenia)
In 98% of deaths, the heat injury occurred within a residence. Upon review of living conditions, deaths occurred more frequently in:
Persons that lived alone
Homes without cooling systems- such as air conditioners or fans
7% of individuals had air conditioners, 24% had fans in the residence
Neighbourhoods that were socially or materially deprived
Planned action after this event:
Implementation of a coordinated provincial heat alert and response system
Identifying populations at greatest risk, identified by Home and Community Care Services and developing messaging for these populations
Long-term risk mitigation by increasing public service messaging on heat preparedness, and increased cooling requirements in future building codes. [4]
Extreme Cold
During the winter months, temporary winter response shelters, and extreme weather response (EWR) shelters are available throughout British Columbia. This information is currently shared with service providers, outreach teams, and TransLink. Future physicians can support patient health by being aware of local extreme cold weather alerts, discussing this with patients experiencing homelessness, or without adequate heating and providing resources.
Resources for Patient Information
Emergency Shelters - Locate shelters in British Columbia
Emergency Preparedness- How to prepare and stay safe in the extreme cold
Government of Canada - Steps for cold weather safety
