Clinicians Urged to Act as Heat and Homelessness Collide in Record-Breaking Crisis

Following the hottest year ever recorded and the highest single-night count of homelessness in U.S. history in 2024, a new editorial in JAMA Internal Medicine is calling on health care professionals to take urgent, proactive steps to protect people experiencing homelessness from heat-related illness and death.

The editorial, “The Converging Crises of Extreme Heat and Homelessness,” urges clinicians and health systems to:

• Screen all patients for housing status, especially during extreme heat events
• Adjust medications that can impair the body’s ability to regulate heat, such as diuretics, antipsychotics, anticholinergics, and stimulants
• Provide guidance on hydration, heat warning signs, and local cooling resources
• Collaborate with shelters and outreach organizations to reach unhoused patients who may not receive weather alerts

“We’re not just dealing with rising temperatures — we’re dealing with rising risk,” said Sharon K. Inouye, MD, MPH, senior scientist, Milton and Shirley F. Levy Family Chair, and director of the Aging Brain Center at the Hinda and Arthur Marcus Institute for Aging Research, and co-author of the editorial. Inouye is also the editor-in-chief of JAMA Internal Medicine. “Clinicians must treat housing status like a vital sign during heat emergencies.”

Study shows unhoused Americans face extreme risk

The call to action is grounded in alarming new data from a national study, “Heat-Related Illness Among US Patients Experiencing Homelessness,” by Weckstein et al., simultaneously published in JAMA Internal Medicine.

Using the largest all-payer emergency department database in the U.S., the researchers found that in 2021 and 2022, people experiencing homelessness had 604 heat-related emergency department visits per 100,000 individuals — a rate nearly 30 times higher than among housed adults.

The study also found that unhoused individuals were significantly more likely to require hospitalization once in the emergency department for heat-related illness.

A crisis reaching new highs

The findings come during a historic convergence of environmental and humanitarian crises:

• 2024 was the hottest year on record globally, topping 2023.
• On a single night in 2024, over 770,000 people were experiencing homelessness in the U.S., the most ever recorded — a shocking 18% year-over-year increase.

People experiencing homelessness face unique and compounding risk factors during extreme heat: prolonged exposure to sunlight and pavement, lack of access to air conditioning, co-occurring medical and psychiatric conditions, substance use, social isolation, and minimal access to water, restrooms, or shaded spaces.

Older adults face growing threat of homelessness and heat illness

The crisis is also putting older adults living on low or fixed incomes at growing risk. With rents rising faster than benefits and affordable housing in short supply, many older people are increasingly vulnerable to losing their homes. Older adults are less able to regulate temperature, making this population especially susceptible to heat-related illness — even before housing is lost.

“Many seniors are just one setback away from homelessness,” Inouye said. “Without intervention, more will be exposed to life-threatening conditions during extreme heat.”

Long-term and short-term solutions must work together

While permanent supportive and affordable housing remains the most effective long-term solution, the letter calls for immediate policy and clinical action:

• Expand access to shelters and cooling centers that account for real-world needs — offering water, shade, restrooms, pet accommodation, and secure storage
• Invest in housing as a public health strategy, which can reduce hospital visits and Medicaid costs
• Implement climate action to reduce fossil fuel use and mitigate the long-term trajectory of extreme heat

The authors underscore the bidirectional link between heat and homelessness: not only does being unhoused increase vulnerability to heat-related illness, but extreme weather and rising costs can drive marginally housed people into homelessness.

In addition to Inouye, authors of the editorial included first author Nathan M. Stall, MD, PhD, JAMA IM Editorial Fellow, Division of Geriatric Medicine, Department of Medicine, University of Toronto; and coauthors Giselle Corbie, MD, MSc, Kenan Distinguished Professor of Social Medicine; Director, Center for Thriving Communities, Professor, Internal Medicine at UNC School of Medicine; and Cary P. Gross, MD, Professor of Medicine and of Epidemiology, Founder and Director, Cancer Outcomes, Public Policy and Effectiveness Research (COPPER) Center, Yale School of Medicine.

About Hebrew SeniorLife
Hebrew SeniorLife, an affiliate of Harvard Medical School, is a national senior services leader uniquely dedicated to rethinking, researching, and redefining the possibilities of aging. Hebrew SeniorLife cares for more than 4,500 seniors a day across campuses throughout Greater Boston. Locations include: Hebrew Rehabilitation Center-Boston and Hebrew Rehabilitation Center-NewBridge in Dedham; NewBridge on the Charles, Dedham; Orchard Cove, Canton; Simon C. Fireman Community, Randolph; Center Communities of Brookline, Brookline; Jack Satter House, Revere; and Leyland Community, Dorchester. Founded in 1903, Hebrew SeniorLife also conducts influential research into aging at the Hinda and Arthur Marcus Institute for Aging Research, which has a portfolio of more than $98 million, making it one of the largest gerontological research facilities in the U.S. in a clinical setting. It also trains more than 500 geriatric care providers each year. For more information about Hebrew SeniorLife, follow us on our blog, Facebook, Instagram, Threads, and LinkedIn.

About the Hinda and Arthur Marcus Institute for Aging Research
Scientists at the Marcus Institute seek to transform the human experience of aging by conducting research that will ensure a life of health, dignity, and productivity into advanced age. The Marcus Institute carries out rigorous studies that discover the mechanisms of age-related disease and disability; lead to the prevention, treatment, and cure of disease; advance the standard of care for older people; and inform public decision-making.