It’s going to be a very long day for the 1,500 runners who’ve embarked on a 24-hour ultra-marathon that goes in loops around the River Drives.

It’s all about staying alive on this course. Runners like Juliann Holtz of Manayunk are in it for distance not for speed:

“I’m going to do a run-walk, run-walk system. last year I ran 89 miles so this year I hope I can break 100.”

Holtz was a little concerned about the heat. This is the third year of the race and this is the hottest it’s ever been.

Proceeds go to “Back on my Feet,” a program that helps homeless people by getting them in a running program. Founder Anne Mahlum isn’t running it herself but she says it’s been a great event for the non-profit:

“When we were looking at what event to do, we were just looking at the void in the running community. There are lots of 5 K’s and 10 K’s but there was nothing of this magnitude.

The Utlra is rounded out by less intense events, such as midnight madness and the pajama run. They also provide company for the runners who are slogging it out through the night.