A marathon is not just race designed to test the physical and mental endurance of a person, but also an exclusive club consisting of one percent of all athletes. After 26.2 miles of wear and tear on the body, plus months, and even years of marathon training, most runners need to spend weeks on recovering from the journey — but not Tim Durbin.

The 31-year-old San Francisco resident decided to push his body to the limit and enter The World Marathon Challenge, which he completed Friday. The contest took him to all seven continents around the world. He ran in Union Glacier, Antarctica; Punta Arenas, Chile; Miami, U.S.A.; Madrid, Spain; Marrakesh, Morocco; Dubai, United Arab Emirates; and Sydney, Australia. He ran one marathon each day for seven days, along with 11 other runners from around the world.

“And done!” Durbin posted on Twitter, after running the last race in 4 hours 55 minutes in Sydney, where he plans to vacation and finally recover over the next week. He said he had needed that rest since he finished his fourth race, and the nonstop physical exertion began to set in.

Each day he spent between four and six hours running, and nearly twice that much time traveling. In between the races and plane rides, he slept as much as he could during small intervals filled with jetlag and lactic acid buildup. He began experiencing the consequences of the quick turnarounds before his fifth race in Marakesh. It "was the second in less than 24 hours and started seven hours after finishing Madrid,” Durbin told The Chronicle. “It was cold and drizzled a bit as well.”

The weeklong test of endurance and willpower was only one part of his ambitious bucket list goal of logging a distance of 24,901 miles — the circumference of the world’s equator. Not only did Durbin resist succumbing to the sheer physical exhaustion, he also spent the year fundraising. In honor of several of his family members’ battles with cancer, he raised $77,777 for the V Foundation for Cancer Research.

“When thinking about the World Marathon Challenge during the numerous 'lonely’ hours spent running or walking around San Francisco in 2014, I realized that even if I do finish 'last’ I won't be finishing last at all,” Durbin wrote in his online journal. “I dared to do something that most people view as impossible.”

What Does It Take?

It does seem impossible. Within the first 48 hours of the first half of his journey, Durbin ran three marathons on less than nine hours of sleep. During a marathon, the body loses heat and heat production by 10-fold. What happened to Durbin's body when he ran through Antarctica’s below freezing conditions may have accelerated muscle weakness and the disorientation the typical body goes through in extreme temperatures.

By the time he set foot on Australia’s summer-hot starting line, the high humidity levels likely reduced evaporation, increased dehydration, and impaired his ability to transfer heat from the muscles to the skin — a trick the body does to cool itself down. Body heat is lost through the evaporation of sweat, along with the heart’s ability to control body temperatures by supplying oxygen-rich blood to the body.

Even if the body is fully functioning and sweating, it’s not uncommon for marathon runners to cross the 26.2-mile mark with body temperatures as high as 105 degrees, according to Marathon and Beyond. Multiply that by seven and Durbin has put his body through 183.4 miles of extreme temperatures, sleep deprivation, and a demonstration of extreme physical ability.