He’s lived underwater for over 75 days. He thinks others should, too.

Every day, Joseph Dituri wakes up around 5 a.m., walks to his work station and basks in the sun that hovers above him. This sun, however, is a yellow pillow with a smiling face in the center. Dituri hung it on his wall to remind him of the real sun, which he hasn’t seen in more than 75 days.

Dituri, a hyperbaric medicine researcher and associate professor at the University of South Florida, has been living in an underwater pod in Key Largo, Fla., since March 1. He’s exploring whether living underwater is possible through daily tests on his brain, heart, lungs and blood.

On Saturday — his 73rd day at Jules’ Undersea Lodge — Dituri believes he broke the world record for the longest stint living underwater. But Dituri, 55, is still determined to live submerged for 100 days to complete his experiment.

“It’s not about the world record,” Dituri said.“it’s about living underwater and in an isolated, confined, extreme environment.”

Dituri knew living underwater was possible. In 2014, two Tennessee professors stayed in Jules’ Undersea Lodge, an underwater hotel in Key Largo, for 73 days. Since watching his military colleagues suffer concussions during the wars in Iraq and Afghanistan, Dituri has studied treatments for traumatic brain injuries. He wondered whether living underwater in a pressurized environment could aid brain injuries.

“I said, ‘We have to live in the ocean,’” Dituri said. “everybody was like, ‘You’ve gone crazy.’ I was retired from the Navy, and they’re like, ‘That’s it. You’ve lost it.’”