From the Overview: "Extreme heat events pose a serious danger to people throughout the United States. Studies conducted by the Centers for Disease Control and Prevention (CDC) have shown that exposure to extreme heat can increase discomfort and fatigue, cause heat cramps, and increase emergency room visits and hospitalizations. It can also kill. From 1999 through 2009, extreme heat exposure caused or contributed to more than 7,800 deaths in the United States. Extreme heat is a real danger to human health that will become worse with time. Experts project that as our climate changes, extreme heat events in the United States will become more frequent, longer lasting, and more severe. By the end of this century, extremely high temperatures that currently occur once every 20 years could happen as often as every two to four years. Learning about how to prepare for and respond to extreme heat events will help protect our communities, especially the most vulnerable populations, from avoidable death and hardship. This document describes extreme heat events, how an extreme heat event threatens public health, and how to prepare for and respond to such an event. It explains how the frequency, duration, and severity of extreme heat events are increasing as a result of climate change, and includes links to local programs and real-world examples from across the country."
Centers for Disease Control and Prevention: http://www.cdc.gov/