CLEARWATER, Fla. -- A longtime City of Clearwater lifeguard says he is thankful to be alive after a group of his former students came to his rescue.

Clifford Patterson, 66, suffered a heart attack doing water workouts last weekend at Morningside Recreation's pool in Clearwater.

"It looked like I was gone," said Patterson.

Turns out, the lifeguards on-duty were trained by Patterson himself.

Patterson has taught thousands of people over the years how to swim safely and save a life, if needed.

"It was honestly one of the happiest moments of my life just to hear that he was OK and that he was able to come to," said lifeguard Cameron Gasky.

Patterson spent two days in Morton Plant Hospital' intensive care unit. Doctors credit those young lifeguards for bringing Patterson back to life.

William Armstrong, 17, rescued Patterson during a mock drowning exercise just a few months ago.

"It came full circle because I went from training to save Cliff to actually saving his life."

ABC Action News was there Friday when Patterson thanked the five lifeguards who saved his life.

"I'm glad I trained you well or I wouldn’t be here and I guess God didn’t want me yet," said Patterson.