New York researchers identify 90 degree threshold as critical risk for heat stroke in vulnerable older adults

NYU researchers find that older adults in underserved areas face heat stroke risks at 90°F, lower than the 95°F threshold used for NYC municipal alerts.

By: AXL Media

Published: Mar 21, 2026, 6:09 AM EDT

Source: Information for this report was sourced from NYU Langone Health

The Rising Threat of Extreme Heat for Seniors

National heat-related mortality has increased by nearly 17 percent annually since 2016, a trend that disproportionately impacts the elderly. Older adults possess a higher biological risk for heat stroke due to age-related changes in thermoregulation and a higher prevalence of chronic conditions such as heart disease, diabetes, and kidney failure. Furthermore, many seniors take medications that further impair the body's ability to shed heat, making them a primary focus for public health interventions during the summer months.

Disparities in Climate Resilience and ED Use

To understand how heat affects different populations, NYU researchers compared two emergency departments (EDs) within the same health system. ED-1 serves a socioeconomically and racially diverse population with a Medicaid enrollment rate twice as high as ED-2. The study found a stark contrast: at the more vulnerable ED-1 site, heat-associated risks began at a heat index as low as 66°F, with spikes at 90°F. Conversely, at ED-2, which serves a more affluent, privately insured, and predominantly white population, no significant association between heat and ED visits was observed among older adults.

The Gap in Municipal Alert Thresholds

Currently, New York City issues heat advisories when the heat index is forecast to reach 95°F for two consecutive days or 100°F for any duration. However, the study published in JAMA Network Open suggests these thresholds may be too high to protect the most at-risk citizens. For vulnerable older patients, the danger zone begins five degrees earlier. Researchers estimate that if the healthcare system had used a 90°F trigger for targeted interventions, approximately 116 emergency visits could have been prevented during the study period alone.