Chris Hemsworth is best known for his role as Thor in Marvel’s Cinematic Universe.

The Nordic God of Thunder, Thor has superhuman strength and the ability to use thunder and lightning in battle. He’s one of the strongest Avengers and quickly became a fan favorite due to his charm and clueless sense of humor. Hemsworth has played the iconic character since 2011 when the first Thor film came out and has donned the cape for several movies since.

Hesmworth was given devastating news last year when he found out he was at an increased risk for developing Alzheimer’s due to a genetic anomaly. It changed the actor’s life he reported to Vanity Fair at the time, explaining that he was taking a step back from acting to focus on his family. Now, the actor has faced a scary prognosis a second time with co-star Jeremy Renner’s snowplow accident early this year.

In a recent interview with GQ UK, Hemsworth explained the sobering effect Renner’s accident had on him. “We’re getting to the age now where we’re going to start losing people we love,” the actor stated. He recalled the shock he and his fellow Avengers co-stars felt upon hearing the news and the support they offered Renner in recovery.

Hemsworth went on, explaining that realizing any of them “can go at any minute” makes him anxious. “I don’t think I wanna turn 40. I still feel like I’m 25 and I’ve got heaps of time. Now I’m like, ‘Oh, I could be halfway. More than halfway’… The reality of ‘I’m not going to be here forever’ is sinking in,” the star claimed.

With an unfortunate Alzheimer’s prognosis and coming to terms with a life-threatening accident happening to a close friend, it’s enough to make anyone nervous about the future. Especially for someone like Chris Hemsworth, who’s taken on a role like Thor for so long, it probably feels as though he, too, should be invincible and immortal.