A little over a year ago, Zach Wiener's family experienced a devastating tragedy. The family was on vacation in a summer rental home when, overnight, a fire broke out.
"My parents made it out. I made it out of the window in my bedroom," Wiener, 25, told the TODAY show. But his two sisters — Jillian, 21, and Lindsay, 19 — didn't make it out of the house.
Wiener described the unimaginable grief of losing his two sisters as "a pain and sadness that is more intense than anything I've ever felt. They were my people."
He wasn't sure how to move forward without them or how to honor their memory. But he started by thinking, "How can I do something today that they'd be happy about?"
At first, Wiener gravitated toward fitness, ultimately setting his sights on completing a major challenge: an Ironman race. The grueling three-part competition is made up of more than 2 miles of swimming, 112 miles of cycling and a full marathon.
When he started training, Wiener had never run a marathon, wasn't much of a cyclist and didn't know how to swim. But starting at square one was part of the process for him.
"I remember having a conversation with my therapist and talking about how, in times of grief, a lot of times people will default to what is most natural and comfortable to them," Wiener recalled.
He realized that doing the opposite — setting out to tackle things he didn't think he could do or wouldn't be good at — "would lead to this incredible growth and allow me to have a very, very meaningful year in working towards this goal," he said.
"I was thinking of my sisters and in trying to do something for them, I myself could grow," Weiner explained. "That is what was going to make them proud."
So he teamed up with a coach and started small with drills in the pool, 2-mile runs and 30 minutes on the bike. Slowly but surely, he and his coach kept building up what he was able to do — and proved to himself what he was capable of along the way.
When feeling stuck, he reflected on the little milestones along the way. "How can I possibly take another step forward without my sisters? That feels impossible," he recalled thinking. "It also feels impossible at the beginning to swim five laps."
And he used his training time to reflect on his positive memories of time spent with his sisters. He remembers Jillian as "adventurous, spunky, soulful. But (she) also had this silly goofy side to her," he said. "Lindsay is the epitome of love," Wiener recalled. "(She) would walk into a room and light it up."
Weiner completed the Ironman Maryland competition in mid-September — on his birthday. "It felt like fate," he said.
The 11-hour experience left him feeling exhausted yet exhilarated.
Looking back, Wiener said there have been a lot of parallels between the heavy, seemingly impossible steps of his Ironman journey and his grief journey.
While you may not be ready to run a marathon, the key is "just finding a way to take that (first) step, whether it’s asking a friend for help or telling them you’re not OK," Weiner said. "Finding something meaningful, some way to take that step. You just take that one step."