Running 135 miles nonstop from Badwater, the lowest point in Death Valley, to Mt. Whitney, Calif., the Badwater Ultramarathon staged each July has been called the most demanding and extreme race offered anywhere on Earth.

The blistering heat has put both runners and their support crews in the hospital.

What drives people to press the limits of the human body’s endurance?

Why, for some, is a traditional marathon’s 26.2 miles not enough, and they must compete in ultra-marathons of 62 or 100 miles?

Jeff Lynn, who has a doctorate in exercise physiology and teaches exercise and rehabilitative science at Slippery Rock University, has been on the medical team that ministers to Badwater runners and their support teams.

“We are doing minimal care. We are not there to make life easy, they’ve chosen to be in this marathon,” said Lynn.

Lynn, who ran his first ultramarathon in 2005 and his first marathon in 1987, said it’s the challenge that draws people to these endurance contests.

“At some point, you’ve run your personal best. Your best races are in the past as you get older, it’s a different challenge,” said Lynn.

And the Badwater race is a pretty big challenge, said Lynn.

The temperature can reach 115 degrees.

“People say it’s a dry heat, but so’s your oven,” Lynn said.

Heat illness and heat stroke are serious risks. These can lead to kidney shutdown, brain damage and death.

Lynn said runners can lose 10 pounds in water alone during the course of the race.

Then, since the race starts at 282 feet below sea level and ends on Mt. Whitney at 8,300 feet above sea level, runners must beware of altitude sickness which can lead to severe lung and brain swelling.

Lynn said last year out of 90 runners who started the course, 80 finished it.

Tammy McGaughey of Chicora, who runs 30 to 40 miles of trails a week, said, “The biggest challenge is the endurance of it. You have to be able to last all day and into the night.”

“Why do I love ultra distrance running? I love the challenge and to see what my body is capable of. But mostly for my simple love of running and for what it does for my soul,” she said.

“You have to dial things back,” she said. “Feeling the body is majorly important. You are eating on the run.”

“Ultramarathons are fundamentally different. If you take a 100-mile ultramarathon, it’s not a marathon times four,” said Lynn. “In a marathon, you are not worried about taking in calories. If you are going to run 50 or 100 miles or more, you have to worry about energy management.”

“You have to ingest calories and manage that and you have to manage your hydration. It is fundamentally different for that reason,” said Lynn.

“That’s what drew me into this research: physiology of human endurance,” Lynn said.

So far, 70 miles is the farthest Lynn has run but he did a 12-hour run in West Virginia repeating 6.5-mile laps through the woods.

“It’s how much distance you can cover in the allotted amount of time,” said Lynn.

Successfully completing an ultramarathon “alters the paradigm of what people can do. It raises the bar,” said Lynn. “It’s amazing what you can do if you try.”

“It’s a tribute to what the human body, mind and spirit can do when motivated,” he added.

For McGaughey, who’s completed the 62-mile Oil Creek 100K Trial Run, running has mental as well as physical benefits.

“I find when I’m in the woods, there’s a certain peace. All your thoughts drift through the treetops,” she said.

“Along with that,” McGaughey added, “when I run with my group, it’s such a tight-knit group, the camaraderie is unbeatable. We are like a family on our own.”

Lynn mentioned the same sense of family.

The more you are around it, the more normal it becomes, he said. He pointed out that, according to demographics, ultramarathoners are well-educated high achievers in whatever they do.

“People that are in it have a sense of community. Other sports have it but in the ultramarathoning community it is profound. You could say it’s like a family gathering at these races,” Lynn said.

“It’s kind of like a little reunion every time you go to one,” said McGaughey.