WASHINGTON - Before Pennsylvania Sen. John Fetterman checked himself in to the hospital for clinical depression in February, he walked the halls of the Senate stone-faced and dressed in formal suits. These days, he’s back to wearing the hoodies and gym shorts he was known for before he became a senator.

Male senators are expected to wear a jacket and tie on the Senate floor, but Fetterman has a workaround. He votes from the doorway of the Democratic cloakroom or the side entrance, making sure his “yay” or “nay” is recorded before ducking back out. In between votes this past week, Fetterman’s hoodie stayed on for a news conference with four Democratic colleagues in suits, the 6-foot-8 Fetterman towering over his colleagues.

People close to Fetterman say his relaxed, comfortable style is a sign that the senator is making a robust recovery after six weeks of inpatient treatment at Walter Reed National Military Medical Center, where his clinical depression was treated with medication and he was fitted for hearing aids for hearing loss that had made it harder for him to communicate. His hospitalization came less than a year after he had a stroke during his Senate campaign that he has said nearly killed him, and from which he continues to recover.

“He’s setting a new dress code,” jokes Vermont Sen. Peter Welch, who is the only other newly elected Democrat in the Senate and spent a lot of time with Fetterman during their orientation at the beginning of the year. “He was struggling. And now he’s a joyful person to be around.”

Senators do occasionally vote in casual clothing - Republican Sen. Ted Cruz of Texas, for example, is known for sometimes arriving in gym clothes. But Fetterman’s regular attire is redefining fashion in the stuffy Senate. He’s turning heads on a daily basis as he walks the halls in his signature baggy Carhartt sweatshirts and saggy gym shorts, his hulking figure surrounded by much more formally dressed Washington types buzzing around the Capitol.

The senator’s staff had originally asked him to always wear suits, which he famously hates. But after a check with the Senate parliamentarian upon his return, it became clear that he could continue wearing the casual clothes that were often his uniform back at home in Pennsylvania, as long as he didn’t walk on to the Senate floor.

Welch said Fetterman was quiet and withdrawn when he first came to Washington, and often sat in the back of closed-door caucus meetings. Now he’s standing up and talking, sometimes joking and ribbing Pennsylvania’s senior senator, Democrat Bob Casey.

Fetterman, Welch and Republican Sen. Katie Britt of Alabama became friends at the orientation, and those two colleagues stayed close with him through his recovery. Britt says that in those early days, Fetterman would only really engage if she started the conversation, but they bonded over having children of a similar age and the fact that Britt’s former football player husband, Wesley, is the same height as the Pennsylvania senator. When Fetterman checked into the hospital, Britt’s staff brought food to his office next door.

Britt later visited him at Walter Reed, at his request, and found Fetterman to be totally changed. “When I walked in that day, his energy and demeanor was totally different,” Britt said in an interview.

Now, he’s loud and outgoing, she says - even yelling “Alabama!” at her down a hallway when he caught sight of her last week, giving her fist bumps and asking about her husband and family.

“That shows you the difference that treatment can make,” Britt says. “It’s just incredible to see.”