Extreme heat has caused several hiking deaths this summer. Here's how to stay safe.

In the past two months, at least six people have died in extreme heat conditions in America’s national parks. That doesn’t include two female hikers who died last week in a Nevada state park amid record-breaking temperatures across the state.

From June 2009 through April 2023, there were 60 deaths in U.S. national parks caused by hyperthermia, which is “abnormally high body temperature caused by a failure of the heat-regulating mechanisms of the body to deal with the heat coming from the environment," according to the National Institutes of Health.

With extreme heat blanketing several regions in the USA, Dr. Grant Lipman talked to USA TODAY Sports about staying safe in hot weather.

Thirty years ago, Lipman sustained a knee injury while backcountry skiing in New Zealand. He was 21 years old and an art major in college.

“I came to this realization that I actually was not invulnerable, as I had originally expected,” Lipman said. “That led me to this world of wilderness medicine which is understanding processes of the human body when faced with outdoor health emergencies and how to prepare for and treat these situations.”

He became a physician, and he specializes in emergency room medicine. For 10 years, Lipman was the director of Stanford’s Wilderness Medicine Fellowship. Lipman is also the chief medical officer and founder of GOES, the wilderness medicine app that offers advice, medical assistance, 24/7 access to medical professionals and real-time weather updates. It can be accessed offline when in the backcountry.

MORE:Going for a hike? How to prepare

“It starts with planning," he said. "And when you want to prepare for getting outdoors, you really want to be aware of what you're getting yourself into. And a little bit of information goes a long way to keep you and your family and your group safe.”

Lipman offers tips to stay safe in extreme heat, with assists from the National Park Service and Centers for Disease Control and Prevention:

Plenty of hydration and snacks

Most everyone understands the importance of water or other hydrating fluids while hiking. The National Park Service advises, “The more dehydrated you become, the less efficient your body is at self-cooling. This puts you at greater risk for heat-related illness.”

Lipman also stressed the need for salty snacks. “You can't just drink water,” he said. “You also have to have food and salty snacks. You have to ingest salt, and you have to have calories to mobilize all those electrolytes into your system. So it's food, it's snacks, it's liquid.”

Avoid the hottest part of the day

Early-morning and late-afternoon excursions can keep hikers out of direct sunlight and avoid the day’s highest temperatures. On the Grand Canyon National Park “Plan Your visit” web page, the park advises visitors to “plan your day so you are not hiking between the hours of 10 a.m. and 4 p.m. Take a break near shade and water to avoid the worst heat of the day. Enjoy a predawn start and a late-afternoon finish. 

"Experienced desert hikers know that the timing of their hike is the most important factor in avoiding hazards. Most of the people who need emergency medical help in the canyon due to heat illness are hiking between 10 a.m. and 4 p.m.”

Wear appropriate clothing/hat/sunscreen/sunglasses

Protect your body from harsh elements. There is lightweight, high-tech synthetic apparel that wicks away moisture and provides protection from the sun. A hat can keep sun off your face, sunscreen protects your skin from burning and sunglasses keep your eyes safe.

What heat-related illnesses should you watch for?

According to the CDC, heat rash, sunburn, heat cramps, heat exhaustion and heat stroke are the most concerning conditions. The CDC says all are preventable but getting out of the sun, cooling off and staying hydrated are in-the-moment remedies. With heat exhaustion and heat stroke, it’s important to find a cool spot (shaded areas can be 10-20 degrees cooler, according to the National Park Service) and lower the person’s body temperature with cool cloths or a cool bath in a stream or lake.

Signs of heat stroke include a body temperature of 103 degrees; fast, strong pulse; headache; dizziness; nausea; confusion and loss of consciousness. Heat stroke requires emergency assistance, according to the CDC.

“Cold water immersion is the quickest way to cool someone down, and you’ve got to do that as soon as you suspect any of this because that can save a life,” Lipman said.

Also, pay close attention to children, who don't sweat as readily as adults, "which means their temperature control in heat is not as efficient," Lipman said. Older adults on heart and/or blood pressure medications may be more impacted by heat stress and dehydration.

Make sound judgments

Paraphrasing renowned mountaineer Ed Viesturs, Lipman said, “Going out is optional. Coming back is mandatory.” In other words, understand the circumstances. You don’t have to hike in extreme conditions. You can reduce the length of the hike or not go at all.

“If you're used to doing four-mile hikes and it's 110 degrees, why don't you do a half-mile hike? I'm saying those numbers arbitrarily," Lipman said. "The point being is yes, take it easier and minimize your exertion. … Maybe say, 'This might be a little much. Maybe today's not a good day to go and do that hike.' ”

Lipman also recommends designating an "extreme weather lifeguard.”

“Have one person in the group whose job it is to check in with people," Lipman said. "Make sure they’re hydrating. Make sure they’re keeping cool. Make sure they’re eating salty snacks. Make sure no one’s exhausted and fatigued. Keep an eye on them. Have them rest to cool down. That’s another way of keeping your group and your family safe.”