CHICAGO (CBS)–A nurse is being credited with saving the life of a man who had a heart attack while he was working out at the gym.

Henry “Hank” Gnaidek, 66, was on the treadmill June 14 at his local gym when he suddenly fell off and collapsed onto the floor.

A few treadmills down, cardiac nurse Krista Ryan saw Gnaidek lying there motionless, his treadmill still spinning.

Ryan, who works as a cardiac care nurse at Advocate Christ Medical Center in Oak Lawn, ran to Gnaidek and began CPR.

Someone brought over an AED machine, and she hooked him up until paramedics arrived.

Graidek regained consciousness within a few minutes, and he was taken to the hospital.

“One minute I was working out and the next thing I know I’m waking up on the floor with everyone around me,” Gniadek said in a press release.

At the hospital, doctors found two blocked arteries due to coronary artery disease. He had a surgical procedure where a stent was placed in his heart to open the blockage.

Gniadek expressed his gratitude for Krista. calling her his “hero.”