“After two-and-a-half days in the hospital, I feel great, and after taking a short time off, I look forward to getting back to work," Sanders said in the statement.

Arturo E. Marchand Jr. and Arjun Gururaj, Sanders’ physicians, said that he was stable once he arrived at Desert Springs and then immediately treated at the cardiac catheterization laboratory.

“His hospital course was uneventful with good expected progress. He was discharged with instructions to follow up with his personal physician,” they said.

Asked why the campaign did not reveal he suffered a heart attack until Friday evening, a spokesman for Sanders said "that’s the moment when the most accurate and up-to-date summary could be given by doctors."

The health episode forced Democrats to face a reality that many had been pushing to the side: Their three leading candidates are all in advanced age. Sanders, at 78, is the oldest Democratic candidate, with former Vice President Joe Biden and Sen. Elizabeth Warren at 76 and 70 respectively.

Sanders’ campaign canceled several events this week after he was hospitalized. His aides said Thursday that he would participate in the Oct. 15 debate in Ohio.

His staff also initially canceled its $1.3 million ad buy in Iowa on broadcast and cable television in the wake of his heart attack. But it has since been restored and will begin airing Tuesday.

Sanders has maintained a busy campaign schedule, often making three or four public stops a day. He recently pitched during a softball game with his aides and others in Iowa, and often was seen on the trail shooting basketballs. Until now, he has avoided the same level of scrutiny as Biden when it comes to age, despite being slightly older.

In a video Sanders released on his Twitter account Friday evening, he said, “Hello, everybody. We’re in Las Vegas. I just got out of the hospital a few hours ago, and I’m feeling so much better. I just want to thank all of you for the love and warm wishes that you sent to me. See you soon on the campaign trail.” Sanders’ wife, Jane, added, “Thank you all so much. It really made a difference.”