The long, hot days of summer are here. While that can mean lots of fun in the sun for some, experts warn the extra warmth and exertion also carry the threat of heat-related illness, a problem they expect to increase as climate change spurs longer periods of extreme heat.
According to the World Meteorological Organization, global temperatures are expected to hit record levels in the next five years. Each year in the U.S., an average 702 deaths and 67,512 emergency department visits are due to heat, based on Centers for Disease Control and Prevention data.
Research shows that the more days there are of extreme heat – when temperatures feel like 90 degrees Fahrenheit or higher – the more heat-related deaths occur, including cardiovascular-related deaths triggered by extreme heat.
But even a typical hot summer day can lead to heat-related illness, especially in humid areas, or if a person is overexerting themselves, says Dr. Michael Kurz, a professor and section chief of emergency medicine at the University of Chicago.
What is heat stroke?
Heat stroke occurs when the body overheats and is unable to cool down. There are two types of heat stroke, Kurz notes. The kind brought on by heat alone and the kind brought on by exertion in hot or humid weather. Both can be fatal.
“Non-exertional heat stroke can occur when you’re in a very warm environment, or even if you’re in a less warm environment but the humidity is above 75 percent,” he adds. “When you exert yourself, the body generates even more heat.”
The body gets rid of excess heat primarily through sweat. But when there’s too much heat, the body can’t get rid of it efficiently and core temperature increases.
If body temperature reaches 106 degrees, “the basic chemical reactions in your brain don’t work anymore,” Kurz said. “Your heart rate goes up, you start to breathe quicker, there’s an increased demand for oxygen. These are all things that happen because your body is trying to generate more blood flow to compensate for the increasing body temperature.”
Other organs can begin to suffer, according to Dr. Jason Tanner, a resident in emergency medicine at Yale New Haven Hospital, part of the Yale School of Medicine in Connecticut. “It creates a systemwide failure if it gets bad enough.”
Heat-related illnesses range from the more minor heat exhaustion to life-threatening heat stroke, Tanner says. “Heat illness is a spectrum.”
RELATED: Heat Exhaustion & Heat Stroke: How To Protect Your Children
Are you actually experiencing a stroke?
Signs that a person may be experiencing heat fatigue or exhaustion include