How Extreme Heat Affects People With Chronic Health Conditions

Rutgers experts warn that hot weather can be a danger to all, especially those with diabetes and cancer as well as older adults

As temperatures rise to dangerous levels this summer, extreme heat can create health risks that extend beyond dehydration and heat stroke.

Researchers at the Rutgers-RWJBarnabas Health Center for Climate, Health, and Healthcare warn that hot weather affects health broadly as well as more specifically among people with diabetes, older adults taking common medications and people living with cancer.

Research by Aayush Visaria, Soko Setoguchi and colleagues found that higher outdoor temperatures were associated with an increased risk of emergency department visits and hospitalizations for hypoglycemia among older adults using insulin. Studies conducted in both the United States and Taiwan reported similar findings.

"People often think about dehydration or heat stroke during hot weather, but people who use insulin also face a risk of dangerously low blood sugar," said Visaria, a general internal medicine physician and researcher at the center. "Our research suggests that severe hypoglycemia requiring emergency care may become more common as temperatures rise.

Visaria added: "During hot weather, people who use insulin should monitor their blood sugar closely, stay hydrated, avoid leaving insulin in hot places such as cars and watch for symptoms including sweating, shakiness, confusion, dizziness and unusual fatigue. Low blood sugar can quickly become a medical emergency."

Research by Setoguchi and colleagues found that older adults taking some commonly prescribed medications experienced higher rates of heat-related hospitalization. These included medications used to treat high blood pressure, heart disease, depression and other chronic conditions. The increased risk appeared even during moderately warm weather.

"Many people assume they only need to worry during an official heat wave, but older adults with chronic conditions may remain vulnerable throughout the summer," said Setoguchi, the director of the center and a professor of medicine at Rutgers Robert Wood Johnson Medical School. "Some medications can affect how the body regulates temperature or maintains hydration.

Setoguchi said people shouldn't stop taking prescribed medications.

"Instead, patients and clinicians should include heat in their care plans. Staying hydrated when appropriate, using air-conditioned spaces, avoiding outdoor activity during the hottest parts of the day and checking on older relatives and neighbors can help prevent heat-related illness," Setoguchi said.

Research by Felicia Casanova and colleagues found that people living with cancer often reorganize their daily lives to cope with chronic heat exposure. Participants reported limiting physical activity, reducing social contact, and sometimes delaying healthcare appointments.

"Extreme heat does not only affect the body," said Casanova, a core member of the center and an assistant professor at Rutgers School of Nursing. "It also changes the daily decisions people make about their health. Participants in our study described limiting physical activity, withdrawing from social interactions and sometimes delaying health care appointments to avoid heat."

Casanova added: "As extreme heat becomes more common, health care systems and communities need to help people protect their health without creating new barriers to care, activity, and social connection."