Here you are never alone. You are totally alone. But you are never alone. Because this is very solitary experience.

This is totally solitary. It's true that sometimes you talk to other animals. But that's minutes.

And when I go to sleep, I go to my room. I don't talk to anyone. I sing talking with my wife and family. But mostly, solitude.

Solitude with a lot of people around you.

It's officially spring, that most energizing season. For outdoor endurance athletes, this is when training ramps up, runs and rides get faster, longer.

People really start going for it. This is Michael Roberts. I've been an outside for a couple decades now. And I can tell you that pretty much every year.

My colleagues and I talk about the fact that amateur competitors just keep going harder. Remember when running a marathon seemed like a big deal. For some of us, it still is. But more and more athletes are entering ultra distance events.

Ironmans have turned in a double and triple Ironmans. There are races that have people ascending the vertical equivalent of Mount Everest twice.

Whatever you might imagine, as the most absurd challenge possible, people are out there doing it. Why? Well, talk to anyone who takes on a contest like this. And they'll tell you, it transforms them.

Which brings us to today's episode, a replay from our sweat science series from a few years ago. Our former host, Peter Frick Wright, was hunting around for especially grueling endurance events when he learned about the longest certified foot race in the world.

It's called the Shree Chinmoi self-transcendence 3100 mile race. And it's held in what might seem an unlikely spot, a city block in Queens, New York. So we asked reporter Stephanie Joyce to investigate. I'll let Peter and Stephanie take it from here.

I'm walking down 168th Street. It's a hot summer afternoon. It's probably in the low 80s and sticky. There's no one out on the streets right now. This is just kind of like a nice middle class neighborhood in Queens. I don't see any runners, although presumably this is the block that they run around.

The entire race, all 3100 miles of it, takes place on this single city block. Runners have to do a minimum of 60 miles a day, a little less than two marathons in order to finish the race within the 52 day window.

That means circling the block at least 109 times every 24 hours. But the fastest runners do even more laps. Kobe Orin was on number 111 evening when I caught up with him. He slowed down to a speedwalk while we talked.

You know, the irony here, that you run all day, you go home, you go to sleep. But when you rest, what are you dreaming of? Run into here. Hello.

So I run all day, and then I go to sleep and you're running. That's funny. No, that's tragic.

The race started as a way of paying tribute to the meditation guru Shri Chinmo. His philosophy of self actualization revolved around pushing the perceived limits of human capacity.

He died in 2007, but his followers have continued staging this invite only race every year.

This was Kobe's first year running the race. He's Israeli, and at 46 he was one of the younger competitors. In his day job, he works as a clinical psychologist in Haifa.

He's maybe five, nine, bald and favors brightly colored running clothes. He gives off the vibe of a rubber band stretched tight.

How many laps are you trying to do today? I will do. I'm supposed to do one, one, eight. But I never can do exactly what I'm supposed to do.

Kobe has been running ulcers for 10 years. His first was a 50 mile in 2008. Then he ran 100 mile and then 200 and then 300 until eventually he worked his way up to running a race that was whatever far you could run in 10 days, those put on by Shri Chinmo's followers in 2016.

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