Extreme Heat: A Public Health and Safety Challenge in the Age of Climate Change

As temperatures soared to the 90s Fahrenheit (32-38 degrees Celsius) across the U.S. Midwest and East Coast this week, along with much of southern Europe, authorities and public health experts issued heat warnings to help keep people safe from the extreme heat. Heat can affect health in various ways, with heat exhaustion causing symptoms such as dizziness, shakiness, thirst, and headaches. While these symptoms are usually not serious unless the person is unable to cool down within 30 minutes, heatstroke can be a medical emergency defined as the body's core temperature going above 40.6 Celsius (105 Fahrenheit). Symptoms of heatstroke include rapid breathing, confusion, seizures, and nausea, which can lead to long-term organ damage and death without medical attention. High temperatures are especially dangerous when combined with high humidity, which makes it harder for people to cool down by sweating. Both are expected to rise with climate change, as warmer air can hold more moisture. While extreme heat can be harmful to anyone, some populations are more vulnerable than others. Experts are most concerned about older people, young babies, and people who are socially isolated. They also worry about outdoor laborers and people struggling economically. People with pre-existing health conditions, such as lung disease, heart problems or diabetes, should also be extra cautious. Experts say more deaths occur earlier in the summer when people's bodies have not had a chance to acclimatize. Apart from testing a body's ability to regulate its own temperature, extreme heat can pose a host of secondary risks. Warmer temperatures encourage the growth of bacteria and algae, raising the risk of water being contaminated with diseases such as cholera or of lakes and rivers becoming choked with toxic algae. Heat can also damage crops or buckle roads and disrupt transport systems. Wildfires fueled by dried-out trees or shrubs can lead to dangerous levels of air pollution. Heat stress, including the sleep disruption caused by heat, can also contribute to poorer mental health. Medical experts expect that certain diseases will expand their ranges as climate change enables disease-carrying insects to move into new areas. For example, we could see more of the deadly, tick-borne Powassan virus, while scientists have also mapped the expanding habitat of Aedes mosquitoes, which carry dengue, Zika virus and chikungunya. In California's Central Valley, desert-loving fungal spores that cause Valley fever could do well as temperatures climb. To combat the risks of extreme heat, public health advisories across the United States urge people to stay cool, stay hydrated, and avoid over-exertion. Many cities have set up public cooling centers or are providing free access to air-conditioned public transport. Employers should ensure workers have adequate breaks and hydration, and that they are not working outdoors when the heat is dangerous. Additionally, individuals should consider wearing lightweight and light-colored clothing to reflect sunlight and reduce heat absorption. Finally, it is important to monitor weather forecasts and take appropriate precautions when high temperatures are expected in the area.