PHILADELPHIA — As anyone who has attempted to move around outside in extreme heat can attest, steamy days in the mid-90s are hard on the human body.
In the worst-case scenario, a stretch of hot days and, especially, hot nights can be deadly, particularly for older people who live in ovenlike rowhouses without air-conditioning.
Benjamin Abella, an emergency medicine physician at Penn Medicine, is also worried about roofers and construction workers who are hurrying to finish projects during the city's housing boom. But anybody who is out for long periods working, gardening, or exercising is at risk for heat-related illness in weather like this.
Here's what you need to know:
Q. How does the body cope with heat?
A. Our bodies regulate their temperature in extreme heat by sweating. The sweat evaporates, which cools the skin. This makes your heart rate rise as your body sends more blood to the skin to provide the energy for all that extra sweating, said Edgar Chou, an internal medicine physician at Jefferson Health. This can divert blood from other parts of your body, like your brain or gut. It also uses a lot of fluid, which is why it's important to drink enough. "You lose a lot more water than you realize — and salt," Abella said. High humidity makes things worse, because sweat won't evaporate as quickly.
Q. How can I tell symptoms of heat exhaustion or heatstroke?
A. Dehydration is the primary problem in extreme heat. Symptoms progress along a continuum, from heat exhaustion to far more serious heatstroke. The Centers for Disease Control and Prevention show overlap between heat exhaustion and stroke symptoms.
In the early stages, people sweat a lot and feel thirsty. Urine becomes darker in color. With heat exhaustion, people may feel tired, dizzy, and weak, Abella said. Headaches and nausea are also common. "We all have to listen to our bodies carefully," he said. "The folks who get in trouble push through."
In heatstroke, the body has lost its fight to keep its temperature down. People may stop sweating and develop fevers of 103 degrees and up. This is an emergency that requires immediate medical attention. It can cause organ damage and death. Chou said he becomes concerned when patients have temperatures over 100 degrees. People with heatstroke may also become confused or pass out. If someone is vomiting and unable to drink, they likely need medical help, Chou said.