Urban heat islands linked to worse recovery after major surgery

by American College of Surgeons

edited by Sadie Harley, reviewed by Andrew Zinin

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Patients living in areas with more intense urban heat were less likely to have an optimal recovery after major surgery, according to new research on nearly 700,000 patients.

The research was presented at the American College of Surgeons (ACS) Clinical Congress 2026 in Washington, held Sept. 26–29.

Above an urban heat island intensity threshold of 2.19°C, or about 3.9°F, each additional 1°C (1.8°F) was associated with 8% higher odds of not achieving a "textbook outcome." In this study, a textbook outcome required no complications, no readmission, no prolonged hospital stay and survival for at least 30 days.

An urban heat island is a developed area that is warmer than its surroundings. Roads, buildings and other infrastructure absorb and re-emit more heat than natural landscapes, while limited trees and vegetation reduce shade and natural cooling. The temperature difference can vary substantially across neighborhoods within the same city.

"Heat isn't only uncomfortable; these data suggest it can have a real impact on surgical recovery," said Timothy M. Pawlik, MD, Ph.D., MPH, MTS, MBA, FSSO, FACS, senior author of the study and professor and chair of the Department of Surgery at The Ohio State University Wexner Medical Center in Columbus, Ohio.

"It's something health care providers need to be aware of. We need to screen for heat exposure and connect at-risk patients with resources."

Satellite data linked neighborhood heat to surgical recovery

The research team developed the Adaptive Spatiotemporal Environmental Thermal Health Exposure Resolution framework, a method for estimating heat exposure in the areas where patients live. The framework used satellite-derived temperature data to link patients' residential areas with urban heat island intensity, postoperative outcomes and community characteristics.

The study included 697,552 patients who underwent major surgery across 3,144 U.S. counties. Their average age was 76.

Overall, 50.2% of patients achieved a textbook outcome. Across the cohort:

• 25.2% experienced complications
• 22.9% had a prolonged hospital stay
• 14.8% were readmitted
• 7.1% died within 30 days

The relationship between heat and suboptimal surgical recovery was stronger among Black patients and residents of communities with high Social Vulnerability Index scores, a composite measure of community-level social and economic vulnerability.

When the researchers restricted the analysis to urban heat island exposure above 2.19°C, the association was particularly pronounced among patients undergoing cancer-related, emergency or high cardiac-risk procedures.

Pawlik said dehydration and changes in the body's fluid balance during high heat may be one possible explanation for the stronger association among cardiac patients, who may have less ability to tolerate those stresses.

Heat risk may need to be part of discharge planning

The findings suggest that surgical teams may need to consider not only whether a patient is medically ready to leave the hospital, but also whether the patient can recover safely in the environment to which they are returning.

"Do you have air conditioning in your house? Do you have a fan? Are you going to be able to stay hydrated?" Pawlik said. He added that questions about heat exposure may need to be increasingly incorporated into discharge planning.

Access to cooling is not equal. People at higher risk during extreme heat include older adults, people with chronic health conditions or disabilities, people with limited incomes, people experiencing homelessness and those who do not have access to safe, adequately cooled housing.

Many communities open cooling centers during periods of extreme heat. Hospitals, patients and caregivers can use a state-by-state directory of cooling center resources to identify potential local assistance.

Because the study was observational, it identifies an association and does not establish that residential heat exposure caused the worse outcomes.

More information

Wang, J, et al. Heat Island-Related Surgical Outcome Burden under Global Warming, Demographic and Adaptation in 3,144 Counties across the United States

Clinical categories

Preventive medicineGeneral surgeryHealthy aging Provided by American College of Surgeons Who's behind this story?

Sadie Harley

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Citation: Urban heat islands linked to worse recovery after major surgery (2026, September 25) retrieved 25 September 2026 from https://medicalxpress.com/news/2026-09-urban-islands-linked-worse-recovery.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.