Bodybuilder Rich Piana Alive & Fighting After Medical Emergency, Girlfriend Says

Bodybuilding superstar Rich Piana is alive and fighting for his life after a medical emergency in Florida this week ... so says his girlfriend.

TMZ Sports has learned ... Piana's fitness model girlfriend, Chanel Jansen, was with Piana when he collapsed and hit his head on Monday afternoon.

Sources tell us ... Chanel administered CPR on the massive 46-year-old until help arrived.

He was transported to a nearby hospital where he was put in a medically induced coma.

There were rumors that Piana died from his injuries -- but Chanel says that's just not true.

" I just want to be clear [Piana] is STILL ALIVE," Chanel says ... "All myself and his family are asking for is POSITIVE thoughts, prayers, and love."

Piana is a former Mr. California who went on to become a huge Instagram sensation -- racking up more than 1 million followers with pumped up photos and videos.

He's a staple on the bodybuilding circuit and has worked out with some of the biggest stars in the sport -- including the guy who plays The Mountain on "Game of Thrones."