by June Kaminski, RN MSN PhD(c), OJNI Editor in Chief
2021 has been an eventful year, with the continuation of the COVID-19 pandemic and record extreme heat patterns across much of the globe. Heat waves are not inclusive to this year, but high temperature records have certainly been broken – and it is predicted to get worse in the coming years. This means that responses from healthcare systems will need to be timely, prepared, and effective. “It is currently assumed that potential heat waves and prolonged periods of heat in the summer months will place an additional burden on many healthcare systems, coinciding with the COVID-19 pandemic” (Bose-O’Reilly et al., 2021, p. 5).
The health risks of extreme heat are well documented but not well known to the general public. Healthcare professionals at all levels from public health to acute care can be instrumental in shifting the public misperceptions about heat and health risks, and in linking people to tools that can help them self-manage their susceptibility to these risks. This is important, since heat waves have been nicknamed “the silent killer” (Natural Resources Defense Council, 2018) and it is becoming clear that “extreme heat causes more deaths than any other weather-related hazard” (Center for Climate and Energy Solutions, 2017, p. 1). “Heatwaves have been linked to increased risk of mortality and morbidity and are projected to increase in frequency and intensity due to climate change” (van der Linden, 2019, p. 2).
This is particularly true with vulnerable populations at risk. “Before heat waves occur, city and state emergency management and health services should consider heat vulnerability in their community with special attention on the most vulnerable to heat stress: older adults, infants and children, people with chronic conditions, low-income residents, and outdoor workers” (Center for Climate and Energy Solutions, 2017, p. 6).
Extreme Heat Health Risks
The health effects of extreme heat depend not only on the actual temperature but also on the heat index which “indicates what the temperature actually feels like to the human body, taking into account relative humidity or other factors such as air humidity, sun exposure and wind speed, depending on the index used” (Global Heat Health Information Network, n.d. Understanding Heat).
Physical symptoms of heat-related distress are varied, depending on a person’s current health condition, as well as their socioeconomic and environmental situation. “Prolonged exposure to extreme heat can cause heat exhaustion, heat cramps, heat stroke, and death, as well as exacerbate pre-existing chronic conditions, such as various respiratory, cerebral, and cardiovascular diseases. These serious health consequences usually affect more vulnerable populations such as the elderly, children, and those with existing cardiovascular and respiratory diseases. Socioeconomic factors, such as economically disadvantaged and socially isolated individuals, are also at risk from heat-related burdens” (National Institute of Environmental Health Science, n.d., Climate and Human Health). When prolonged, extreme heat can tax existing health services by sparking marked increase in demand for interventions. “Increased use of healthcare services during periods of extreme heat is a concern to health-care professionals and policymakers worldwide” (van der Linden, 2019, p. 2).
Mental health can also be affected by extreme heat patterns. “Complex cognitive tasks such as working memory (spatial span test, pattern recognition) have been observed to be significantly impaired because of heat stress” (Cooper, 2019, p. 2). Besides impaired cognition, Cooper also discussed the effects of heat on promoting violence, suicide, insomnia, and even more stress for people with “severe psychotic or mood disorders, substance abuse disorders, or cognitive impairments” (Cooper, 2019, p. 3). “Heat influences brain functioning and behaviour, and people with mental health issues and/or prescribed medications which limit the body’s natural cooling functions are especially vulnerable” (Global Heat Health Information Network, n.d., Heat and Health).
Negative health impacts of heatwaves are predictable and preventable via public health actions. Therefore, PAHO/WHO urges countries in the Americas Region to:
- Strengthen health sector capacities and capabilities via the development of heatwave action plans comprising preparedness and response to this threat, and by doing this, prevent and reduce the excess of heat-related illness, deaths, and social disruption resulting from heatwaves; and
- Strengthen the capacities and capabilities of meteorological services to generate projections and predictions relevant to human wellbeing, and to promote close coordination between these services and the health sector, so that meteorological information is used for decision making, before, during and after a heatwave strikes.” (Pan American Health Organization and World Health Organization., n.d., p. 1).
Healthcare services across the globe are currently working with intersectoral organizations to improve the health and well-being of communities exposed to extreme heat. “Many communities have developed programs in partnership with public health, social services, and emergency response departments to respond and protect people from heat impacts. These entail public education campaigns as well as providing services and cooling centers” (Cooper, 2019, p. 3). “Local and state governments are already deploying resilience strategies to address urban heat islands, prepare for long-term trends of higher temperatures and plan emergency responses for heatwaves” (Center for Climate and Energy Solutions, 2017, p. 1).
According to the Global Heat Health Information Network, (GHHIN, n.d., Take Action). it is important for all communities to develop and maintain Heat Action Plans that include the following elements:
- Inter-sectoral coordination
- Heat health early warning and alert systems
- Communications and public outreach
- Reduction in indoor heat exposure
- Special care for vulnerable people
- Preparedness of the health and social care systems
- Long-term urban planning
- Real-time surveillance
“Heat health warning systems (HHWS) are a critical part of identifying, preparing, and responding to heat risks. Heat health warning systems are decision tools developed jointly by epidemiologists and meteorologists. All HHWS develop impact-based forecasts which establish when temperature and humidity conditions will locally produce heat at a level which is dangerous to human health and may result in heat illness and mortality” (Global Heat Health Information Network, n.d., Understanding Heat).
Healthcare service providers can work in tandem with heat health warning systems by tracking current weather patterns and planning quality strategies for sharing information and directives with the general public. Important strategies include communication, education, health alert systems and surveillance of heat related symptoms, morbidity, and mortality. A variety of virtual tools have been developed to support these strategies.
Communication strategies are important for alerting the public about impeding extreme heat patterns as well as how to cope with the heat once it hits. “A communication strategy is an integral part of a heat response plan. Health departments can use various types of communication methods to reach the most at-risk populations, as well as critical partners and community organizations, during an extreme heat event” (Hines, 2020, p. 2).
“Comprehensive and effective extreme heat event notification and response programs can be developed and implemented at a low cost. Instead of creating a separate heat preparation office or program, cities and states can instead plan for short-term reallocation of existing resources in an extreme heat event” (Center for Climate and Energy Solutions, 2017, p. 6-7).
Nurses and other health professionals can apply several virtual apps or web-based tools that have been developed to support communication, educational, tracking, and surveillance strategies in their practice.
Tools that support communication strategies with the public and intersectorally include:
Extreme Heat Safety Social Media Toolkit
Developed by Ready.gov
The Extreme Heat Safety Social Media Toolkit has safety and preparedness messages that health professionals and the public can share on social media channels.
Home Cooling Tips messaging toolkit
Developed by the C40 Cities Climate Leadership Group
This messaging toolkit provides materials that can help to raise awareness of heat risk, and the compounded risks of heat and COVID-19, in various cities. It also promotes easy, low-tech and low-cost measures residents can take to stay cool in their homes.
iTree Desktop Tools
developed by USDA Forest Service and Partners
These web-based tools help professionals communicate and strategize on how trees can be planted and organized to significantly reduce the effects of extreme heat. Variations of the tools calculate the benefits of trees within the context of landscaping, design, canopy, ecology, and water preservation.
Heat Resilient Cities Benefits Tool
Developed by the C40 Cities Climate Leadership Group
The Excel-based tool has been designed to help decision-makers to quantify the health, economic and environmental benefits of common urban heat adaptation actions. Users can calculate the benefits brought by specific parks and green infrastructure, water bodies such as rivers and lakes, and cool and vegetative surfaces.
Cool Roofs and Cool Pavements Toolkit
Developed by Global Cool Cities Alliance
This web-based toolkit provides various resources and an evolving Knowledge Base that is a repository for cool surface and urban heat island information.
Educational strategies are one of the most common ways health professionals share extreme heat advice and information with the public. “In addition to communications strategies, many health departments develop trainings and other formal educational activities geared toward a variety of audiences. These educational activities serve as opportunities to improve a community’s resilience to extreme heat events by increasing their awareness of heat’s negative health impacts and promoting strategies to reduce their risk through adaptation” (Hines, 2020, p. 3).
It is important that educational strategies are provided through a variety of venues including word of mouth, printed materials and virtual methods including text messaging, website information, apps, and toolkits. “Determining messaging on heat warnings, safety during heat events, services available, and media channels used to communicate these messages. Consider how to disseminate messages to vulnerable populations, including non-English speakers, and keep in mind that this might require active outreach or checking on vulnerable residents” (Center for Climate and Energy Solutions, 2017, p. 6).
Educational strategies often target the following topics:
- Heat wave early warning systems and Heat alerts
- Warning signs of extreme heat physical and mental effects
- Staying hydrated and avoiding strenuous outdoor exercise
- Where to get easy access to public drinking fountains, swimming pools, and spray pads
- Benefits of green roofs (roofs with plant cover)
- How to access local cooling stations
- Checking in on vulnerable family members, neighbors, populations
- Importance of strategically located shade trees and structures
- Information on how urban forests, including street trees and wooded areas, can mitigate urban heat islands
Strategies include how to manage environments including yards and landscaping. For instance, planting trees can help to reduce local heat quite significantly and provides welcome shade. “Trees and vegetation can reduce heat by shading buildings, pavement, and other surfaces to prevent solar radiation from reaching surfaces that absorb heat, then transmit it to buildings and surrounding air. A number of studies have quantified the cooling effect of urban vegetation. Tree-shaded neighborhoods can be up to 6 degrees cooler than treeless areas and a landscape planned for shade can reduce home air conditioning costs by between 15 and 50 percent” (Center for Climate and Energy Solutions, 2017, p. 5).
Some virtual tools to use and recommend that support educational strategies are:
OSHA-NIOSH Heat Safety Tool App
Developed by Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH)
This app features real-time heat index and hourly forecasts, specific to one’s location, as well as occupational safety and health recommendations from OSHA and NIOSH. It provides recommendations to prevent heat-related illnesses and reduce heat stress in outdoor workers based on local weather conditions used to calculate the heat index.
Developed by the European Research Area for Climate Services
The overall aim of this project was to develop an advanced mobile phone App that integrates weather forecast data into human heat balance models. The personalized app considers individual factors and predicts body responses, provides health risk warning and advice for individuals, public and private sectors, to support decision-making to cope with heat and cold stress when facing extreme weather events such as heat waves and cold spells.
US Climate Resilience Toolkit
Developed by the National Oceanic and Atmospheric Administration
This toolkit is a website designed to help people find and use tools, information, and subject matter expertise to build climate resilience. The goal is to improve people’s ability to understand and manage their climate-related risks and opportunities, and to help them make their communities and businesses more resilient to extreme events.
Red Cross Heat Wave Safety Kit
Developed by the American Red Cross
A practical and easy to follow web-based kit to help people keep themselves and their loved ones safe during a heat wave.
Climate Change and Extreme Heat: What You can do to prepare
Developed by the US Environmental Protection Agency and Centers for Disease Control
This downloadable guidebook provides information about extreme heat and common sense tips for people to prevent heat related illness and keep safe.
Heat Health Alert Systems
“In addition to the communications and education activities, health departments can use heat health alert systems to provide timely messages tailored to groups of people who might be affected by excessive heat. Heat health alert systems might include public service announcements, email and text message alerts, TV and radio coverage, websites, or social media platforms such as Facebook and Twitter. To reduce language barriers in at-risk populations, jurisdictions can consider translating materials to reach these affected populations” (Hines, 2020, p. 4).
Tools that support alert system strategies and their preparation include:
Marine Heatwave Tracker
Developed by Robert Schlegel and the Marine Heatwaves International Working Group
This web application shows up to date information on where in the world marine heatwaves (MHWs) are occurring and what category they are.
Extrema mobile App
Developed by the Extrema Consortium
This app uses real-time satellite data, along with other model and city-specific data to estimate the temperature, humidity, and discomfort index for every square kilometer in the city. Temperature estimates are updated every five minutes, and it also shows personalized heat risk, location of cooling centers, and other resources for participants of involved cities.
Extreme Heat Data Pathfinder
Developed by the National Aeronautics and Space Administration (NASA)
This data pathfinder provides direct links to commonly-used datasets related to extreme heat from NASA’s Earth science data collections.
National Weather Service. Heat Forecast Tools.
Developed by the National Oceanic and Atmospheric Administration
NWS has multiple web-based tools to assess the potential for heat stress due to extreme temperatures. The tools can inform the issuance of NWS official heat watches, warnings, and advisories. Each of these tools integrate other weather parameters to provide a deeper level of information beyond what the actual air temperature can tell us.
Surveillance strategies are a key part of extreme heat preparation and care. Some electronic health records (EHRs) can provide pivotal data to monitor the effects of extreme heat and the resulting demands on the healthcare system. “Some health departments use a technique called surveillance to track and analyze data on indicators of heat-related illness and death, such as heat-related ER visits, Emergency Medical Services (EMS) activity, and death certificate data. Surveillance data can be useful in describing at-risk populations and risk factors within a community, determining targeted interventions, properly timing public health messaging, and managing EMS and hospital staffing to react to medical surge of heat cases” (Hines, 2020, p. 6).
Monitoring this data in real-time can provide important syndromic surveillance information that can inform successful implementation of strategies. “Researchers and health workers agree that syndromic surveillance networks could help improve responses to heat waves and enhance climate adaptation by providing both early warnings of heat-related illnesses or syndromes and evaluating how response efforts can ameliorate those syndromes. These systems can help health departments quickly reach out to fellow practitioners to discuss effective ways to protect vulnerable populations during multi-day heat waves. By combining heat-health surveillance and tracking with climate change-preparedness and prevention, we can help build healthier, more secure communities for today while helping to protect our future” (Natural Resources Defense Council, 2018, p. 2-3).
Tools that support surveillance strategies include:
Heat and Health Tracker
Developed by the Centers for Disease Control
This tracker provides local heat and health information so US communities can better prepare for and respond to extreme heat events. The Heat-Related Illness and Temperature map shows the rate of emergency department (ED) visits associated with heat-related illness (HRI) per 100,000 ED visits by region.
Lancet Countdown. Health Related Mortality
Developed by The Lancet
This indicator tracks global heat-related mortality in populations older than 65 years. It applies the exposure-response function and optimum temperature to the daily maximum temperature exposure of the population older than 65 years to estimate the attributable fraction and thus the deaths attributable to heat exposure.
Extreme Heat Vulnerability Map Tool
Developed by the Centers for Disease Control and Prevention (CDC) and the National Oceanic and Atmospheric Administration
NIHHIS is an integrated information system that builds understanding of the problem of extreme heat, defines demand for climate services that enhance societal resilience, develops science-based products and services from a sustained climate science research program, and improves capacity, communication, and societal understanding of the problem in order to reduce morbidity and mortality due to extreme heat.
US Surface Urban Heat Island Disparity Explorer
Developed by T. Chakraborty and colleagues
This Google Earth-based platform displays census-tract level surface urban heat island (SUHI) intensities for US urbanized areas (polygons with red boundaries), as well as socioeconomic information at the same level of aggregation.
Further Research Needs
Extreme heat is predicted to intensify in the coming years which reinforces the need for further health-related research into the prevention and effects of heat related health risks. The National Institute of Environmental Health Science (n.d.) listed some potential areas of research to consider which included:
- Developing and implementing a standard definition of heat-related health outcomes, as well as standard methodologies for surveillance of outcomes and evaluation of adaptations
- Understanding risk factors for illness and death associated with both acute exposure to extreme heat events and long-term, chronic exposure to increased average temperatures
- Quantifying the combined effects of exposure to heat waves and ambient air pollution on excessive illness and death
- Determining attributes of communities, including regional and seasonal differences, that are more resilient or vulnerable to adverse health impacts from heat waves
- Assessing the health benefits of the use of environmental design principles to reduce high thermal mass of urban areas
- Enhancing the ability of current climate models to capture the observed frequency and intensity of heat waves across various timescales to support weather-climate predictions and use of heat early warning systems in decision making
- Evaluating heat response plans, focusing on environmental risk factors, identification of high-risk populations, effective communications strategies, and rigorous methods for evaluating effectiveness on the local level
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