On Monday the heat index in Austin reached 117 degrees, hottest in the history of the city.

It certainly didn't affect Alex Litt and Cory Sullivan's mission.

"Cory and I in this heat and walking 100 holes, we're trying to replicate that feeling," explained Litt as he marched down the middle of the fairway at Onion Creek.

"We can never replicate that but we can push our bodies as much as we can to - for a second - feel what these people are going through. Like what our fathers have been through."

Cory's dad John died of ALS in 2009, and Alex's dad Marc is entrenched in the battle now.

That's why the duo teamed up for the "100-hole hike to beat ALS". The duo teed up at sunrise and played 100 holes before finishing in the near dark.

"What it means is we want other people to know that others like us are going through it," said LItt. "This is the way we're taking what we're going through and we're joining in this fight."

"People are coming out of woodwork talking about losing a loved one," explained Sullivan. "We share that passion and can build something like this around golf."

"This is year one of many of these."

Doctors diagnose fifteen people per day with ALS. The life expectancy is just 2-5 years after diagnosis.

"That's all we can think about right now," said Litt. "We are developing hope and opportunity for those out there looking for that."

"We've made strides, but we've got a long way to go."