Episode Details

Impacts of Heat Waves on Human Health

Across the United States, climate change is increasing the frequency and intensity of heat waves. A heat wave is defined as a persistent period of high temperature days. Although unusually hot days are a natural part of day-to-day variations in weather, heat waves are becoming more common alongside the rapidly accelerating climate crisis. In major cities across the country, the number of heat waves has increased steadily, from two heat waves per year in the 1960s to six per year into the 2010s and 2020s. In the 1960s, the average heat wave was 2.0 degrees above the local 85th percentile threshold, while the average heat wave during the 2020s has been 2.5 degrees above the local threshold. Approximately 210 million Americans, or two thirds of the population, live in counties vulnerable to health threats from high temperatures. As temperatures increase, the number of heat-related illnesses, emergency room visits, and deaths simultaneously increase. As we head further into the 21st century, adaptive measures to protect human health from the effects of extreme heat waves will be necessary in the face of rising climate risk.

Protecting yourself during extreme heat

Over the past three decades, heat waves have been the leading cause of weather-related fatalities across the nation. In addition to rising heat-related illnesses and deaths, extreme heat can also worsen health outcomes from chronic conditions such as cardiovascular disease, respiratory disease, and acute kidney injury. Extreme temperatures compromise the body’s ability to regulate its internal temperature, resulting in illness, heat cramps, heat exhaustion, heatstroke, and hyperthermia. Individuals living in densely populated cities are extremely vulnerable to the urban heat island effect, which exacerbates high heat temperatures as man made surfaces absorb sunlight during the day and radiate the stored energy at night as heat. Children, the elderly, people experiencing homelessness, low-income communities and individuals with pre-existing health conditions are at the greatest risk to the adverse effects of extreme heat. As temperatures continue to rise, it is necessary that individuals take on adaptive measures to protect themselves from the health risks posed by extreme heat. 

Action can be taken on both a policy and an individual level. Local governments can take steps to help residents reduce their vulnerability to heat through heat management plans and vulnerability assessments. For example, officials can create early warning systems and urban cooling centers for individuals to find refuge. On an individual scale, when you need to go outside, taking preventive measures such as sun protection, hats, and umbrellas is vital to stay cool. Trying to stay inside as much as possible and finding refuge from the heat will help one avoid the risks of heatstroke. More educational initiatives will be vital in informing individuals on risk factors, symptoms, and treatment steps to keep people safe and informed.

Benefits of protecting oneself during extreme heat 

During periods of extreme heat, it is important to take proper care of yourself in order to mitigate the health effects that result from high temperatures such as dehydration, heat stroke, exhaustion, and slowed cognitive function. Taking e