The rising temperatures of summer also mean a rising potential for heat-related illnesses. As the coronavirus pandemic continues, this summer will feature a new heat-related risk factor: face coverings.

“When the heat comes back, we need to be extra cognizant that masks, while important to wear for mitigating the spread of coronavirus, could make things worse for some people,” says Matthew Levy, D.O., M.Sc., an associate professor of emergency medicine at the Johns Hopkins University School of Medicine. “They may result in added stress on the body.”

Health officials encourage everyone to wear a mask outside when around others, and Levy encourages people to be strategic and calculated when going outside, particularly if they have a respiratory condition or underlying health problems that put them at increased risk for COVID-19, such as hypertension, cardiovascular disease or diabetes. Levy also cautions that people should pay attention to signs of heat illness such as dizziness, lightheadedness and dehydration, particularly while wearing face coverings.

Health officials encourage everyone to wear a mask outside around others, and Levy encourages people to be strategic and calculated when going outside with a mask. This, is particularly important for people with a respiratory condition or underlying health problems that put them at increased risk for heat-related illness, such as children under age 4, and those who are overweight or with chronic medical conditions such as hypertension, cardiovascular disease or diabetes. Levy also cautions that people should pay attention to signs of heat illness such as confusion, dizziness or lightheadedness, high body temperature, fainting, loss of consciousness or muscle cramps, particularly while wearing face coverings.

“The same precautions we would ask people who are at risk for heat illness to take, we would recommend here, too,” he says, including going out early in the morning or later at night when it is cooler and limiting time outside in general. It is also important to make sure your home cooling system is working properly, he adds.

Studies show that wearing protective masks can affect the amount of physiological stress on the body and raise the microclimate around the face, Levy says. If it becomes harder to breathe or you feel lightheaded or dizzy under your mask, it’s time to get out of the heat, he says. Levy also stresses the importance of adequate hydration.

How someone will respond to heat stress while wearing a mask depends on a combination of the intensity of the heat, duration of exposure and any underlying medical condition. Regardless of the type of mask, don’t try to make your face feel cooler by dousing the mask in water, Levy says. Getting face coverings wet can compromise their filtration capabilities.

Levy is available for interviews about wearing masks in the heat.

For information from Johns Hopkins Medicine about the coronavirus pandemic, visit hopkinsmedicine.org/coronavirus. For information on the coronavirus from throughout the Johns Hopkins enterprise, including the Johns Hopkins Bloomberg School of Public Health and The Johns Hopkins University, visit coronavirus.jhu.edu