Extreme heat is ‘uncharted territory’ for the public and their healthcare providers.
June 2023- The Journal of Healthcare Contracting
Summer’s almost here. That’s good news, especially for those Up North. But too much heat can be too much of a good thing.
Global temperatures and the frequency and intensity of heatwaves will rise in the 21st century, says the World Health Organization. Debating the cause of rising temperatures may be a job for politicians, but addressing the health implications will fall to hospital emergency departments, public health authorities, community health centers and primary care physicians.
Heatwaves can acutely affect large populations for short periods of time, often triggering public health emergencies, excess mortality and cascading socioeconomic impacts, including lost work capacity and labor productivity, says WHO. But extreme heat has a long-term impact on health as well. Extended periods of high temperatures create cumulative physiological stress on the human body, exacerbating the top causes of death, including respiratory and cardiovascular diseases, diabetes and renal disease.
“We need to start with ensuring that we appreciate that temperatures not typically thought of as hot may pose real risks to health,” says Aaron Bernstein, M.D., interim director of The Center for Climate, Health, and the Global Environment at Harvard T.H. Chan School of Public Health (Harvard Chan C-CHANGE) and a pediatrician at Boston Children’s Hospital. “We need to be able to identify those patients who may be most at risk, and we need to start taking action before heat sets in. That’s why we’ve created resources to help providers make plans in advance for hot weather. With plans in place, which include where to go to stay cool, patients stand a better chance of staying safe. When warm temperatures are forecast, clinics can make outreach to patients at risk to remind them to follow their plans.”
The stuff of headlines
Globally, extreme temperature events are increasing in their frequency, duration and magnitude, reports WHO. Between 2000 and 2016, the number of people exposed to heatwaves increased by around 125 million. In 2015 alone, 175 million additional people were exposed to heatwaves compared to average years. In 2003, 70,000 people in Europe died as a result of the June-August event, and in 2010, 56,000 excess deaths occurred during a 44-day heatwave in the Russian Federation.
In the United States, extreme weather events, especially heatwaves, are the leading cause of weather-related deaths, according to the Centers for Disease Control and Prevention. In the summer of 1995, for example, the City of Chicago endured a heatwave that resulted in at least 469 heat-related deaths and 739 excess deaths during the most intense period (July 14–July 20).
During the last days of June 2021, Pacific Northwest areas of the U.S. and Canada experienced temperatures never previously observed, according to World Weather Attribution, an initiative among climate scientists and climate impact specialists around the world. Temperatures exceeding 40 degrees Celsius (104 F) occurred from Sunday to Tuesday, June 27-29. It is noteworthy that these record temperatures occurred one month before the climatologically warmest part of the year (end of July, early August).
The CDC reported more than 3,500 emergency department visits for heat-related illness in May and June of that year in Alaska, Idaho, Oregon and Washington State. Nearly 80% of the visits occurred between June 25 and 30.
Who’s most vulnerable?
Extremely hot days, as well as days with moderately high ambient temperature and high humidity, can cause increased levels of illness and death by compromising the ability of the human body to regulate its internal temperature, according to the CDC.
A portion of blood from abdominal organs – and in severe cases, all organ systems – is redirected to the skin to accommodate the dissipation of internal heat. Maintaining a steady blood pressure during such significant vasodilation requires an increased cardiac output. The cardiovascular systems of the young and healthy can usually adapt to such demands. However, in the elderly and those with pre-existing cardiovascular conditions (e.g., ischemic heart disease, coronary heart disease, heart failure), the heart is not as proficient at meeting the increased demand required to rid the body of the excess heat.
Others who can be adversely affected by extreme heat include:
- Pregnant women and babies. Studies have shown that the fetuses of pregnant mothers are vulnerable to increasing temperatures, and that exposure to extreme heat during pregnancy can cause congenital heart defects, especially if experienced during particular weeks of gestation, reports CDC.
- People prone to migraines. Dehydration can trigger migraines, according to Cedars-Sinai Medical Center in Los Angeles. In extreme heat events, it’s best to retreat to a dark, quiet room.
- People with multiple sclerosis. MS symptoms – including vision problems, weakness, pain and confusion – can be aggravated when the body gets overheated. This is called the Uhthoff syndrome.
- People with autoimmune conditions, such as lupus and rheumatoid arthritis. Direct sunlight can cause joint pain and fatigue.
In October 2022, researchers reported in JAMA Network Open that the incidence of appendicitis appears to increase when temperatures rise. What’s more, evidence suggests that climate change will affect those with neurological disorders in the near future, including Alzheimer’s and non-Alzheimer’s dementia, epilepsy, Parkinson’s disease and stroke, according to research reported in the journal PeerJ.
Other at-risk groups include people who work outdoors, outdoor athletes, the socially isolated and those with incomes below the federal poverty level, as well as communities of color, reports the National Institute of Environmental Health Sciences. In addition, people living in densely populated cities are more likely to be impacted by the urban heat island effect, where manmade surfaces absorb sunlight during the day and then radiate the stored energy at night as heat.
After studying extreme summer surface temperature events in 1,056 U.S. counties, researchers from the School of Global Policy and Strategy at UC San Diego reported that the poorest tracts (and those with lowest average education levels) within a county were significantly hotter than the richest (and more educated) neighborhoods. In addition, neighborhoods with higher Black, Hispanic and Asian population shares were hotter than the more White, non-Hispanic areas in each county. They ascribed the disproportionate heat surface exposures faced by minority communities to more built-up neighborhoods, less vegetation, and – to a lesser extent – higher population density.
Children are at risk too, given their higher-body surface-area-to-mass ratio and lower sweating capacity, says CDC. In fact, among those suffering heat-related illness, children compose almost half (47.6%), according to researchers at Johns Hopkins University School of Medicine. “In the pediatric population, the most common forms of heat-related pathology occur in exercising adolescents and in children left unattended in vehicles or excessively warm environments,” they found. “Pediatricians must effectively counsel caregivers in recognizing the dangers related to heat exposure and preventing dehydration and [heat-related illness]. When prevention fails, prompt recognition and treatment of heat-related illness become paramount.”
What to do?
“Our rapidly warming climate is bringing us into uncharted territory,” according to World Weather Attribution. “Adaptation and mitigation are urgently needed to prepare societies for a very different future.”
In April 2022, Harvard Chan C-CHANGE announced it would collaborate with relief/development organization Americares in the “Climate Health Equity for Community Clinics Program.” Funded through a grant from Johnson & Johnson, the three-year programs are intended to improve operations in more than 100 safety net health clinics in areas where climate change disproportionately impacts the health of vulnerable communities.
“While we tend to see the greatest effect of heat on health in the first few days of extreme heat, prolonged periods of high heat may promote power outages, affect mental health (in no small part due to people having to curtail normal activities), and in many parts of the world, reduce crop yields and make water scarcer, each of which can affect health too,” says Dr. Bernstein. “Primary care providers can help plan for power outages in particular, especially for patients who rely on electric devices (e.g., CPAP) and through giving appropriate guidance on medication use.”
Sidebar:
Climate-related toolkit for frontline clinics
To help community health centers and clinics better manage care and protect patients from climate risks, the Center for Climate, Health, and the Global Environment at Harvard T.H. Chan School of Public Health (Harvard Chan C-CHANGE) in collaboration with Americares and with financial support from Biogen, released a new “Climate Resilience for Frontline Clinics” tool.
Materials on extreme heat are dedicated to protecting patients with certain health conditions that require tailored guidance, such as asthma, cardiovascular disease, COPD, chronic kidney disease and end-stage renal disease, diabetes, dementia, multiple sclerosis, pregnancy, and mental health conditions. For providers, the toolkit includes chapters on:
- Chronic kidney disease and end-stage renal disease and heat.
- Chronic obstructive pulmonary disease, asthma and heat.
- Cardiovascular disease and heat.
- Dementia and heat.
- Diabetes and heat.
- Mental disorders and heat.
- Multiple sclerosis and heat.
- Pregnancy and heat.
- How to establish a heat action plan.
- How to access weather alerts.
The toolkit can be accessed at americares.org/what-we-do/community-health/climate-resilient-health-clinics/#toolkit.
Discharge-related telehealth consultations are up by 407% in rural areas, and 157% in urban areas (from 2014 to 2018).