More than 160 heat-related deaths have occurred in the last two weeks, as a searing heat wave has rolled across the United States. The dangerous heat has moved from California, across the Midwest to the East Coast, with temperatures climbing to at least 38 degrees Celsius. Extreme heat kills more people each year in the U.S. than any other natural disaster.
Football practice at this high school in the southern U.S. state of Georgia has been canceled following the heat stroke death of 15-year-old Tyler Davis earlier this week. Hakeem Stuart was a friend. "It's not every day you figure one of your friends would just die on you like that."
Tyler Davis and his teammates had been practicing in the hot sun for more than an hour when he collapsed. The temperature had been about 35 degrees Celsius. Three other young athletes have also died of heat related causes this summer.
A construction worker in the midwestern state of Michigan was working in an elevator shaft in 40 degrees Celsius when he had to be rescued.
A young child in the nearby state of Wisconsin was rescued by paramedics after her mother accidentally locked her in the car. "I opened the doors, it was pretty hot in there, so I felt really terrible."
But it is the elderly who are the most vulnerable in hot weather. Doctors say they often have medical conditions affecting their response to heat. Many are on medications restricting their ability to perspire. To make matters worse, many older people live alone and on a limited income. Some try to save money on the cost of air conditioning.
In August of 2003, 10,000 people died of heat-related causes in France. Temperatures reached 40 degrees Celsius. Many of the unidentified were buried by the French government when no one claimed them.
Heat-related deaths in the United States number as many as 400 a year. 1995 was a disastrous year in the Midwestern city of Chicago. A three-day heat wave took the lives of at least 700 people. Again, many were older people who lived alone. Since then, Chicago health officials have reached out to the elderly, checking on them to make sure they are comfortable in the heat.
Former Chicago health commissioner John Wilhelm says the city learned a painful lesson in 1995. "We learned just how insidious heat can be, how it can, day after day, overpower natural defense mechanisms."
Chicago and other large cities are what scientists call "heat islands". Inside these metropolitan areas, the asphalt streets and concrete buildings help make temperatures hotter than in outlying areas. Joseph Romm of the Center for American Progress says that also makes cities less healthy. "Cities that are hotter because of the heat island have more air pollution, more smog, that affects people with asthma and cardiovascular diseases."
If you must go out in the midday sun, medical experts advise you to drink lots of water, wear a hat and watch for possible heat exhaustion. That could mean muscle cramps, headache, nausea and dizziness. The skin may feel cool and sweaty. But when it becomes dry, red and hot -- that could be a sign of heat stroke -- and victims should seek medical attention.