Mike Clark is a swimming coach at Marymount University in Virginia. He’s also spent 30 years working as a lifeguard and is trained in CPR. Above all else, apparently he has an amazing tolerance for cold.

This happened a few months ago, but the story just came out.

Back in April, Mike was at a marina in St. Mary’s County, Maryland, getting something out of his trunk, when he heard a SPLASH in the water. He ran over, and realized a woman had just fallen off her boat.

He jumped into the water, which was a brutal 40 degrees, and swam out to her. She wasn’t breathing, and he was worried she had a neck injury, so he didn’t want to pull her onto the shore.

So he stayed with her in the cold water and performed mouth-to-mouth on her. He shouted for help in between breaths, and fortunately his wife heard him from their boat and called 911.

Thanks entirely to Mike, the woman survived. She woke up FOUR DAYS later in the hospital and couldn’t remember what happened but she says she’s eternally grateful to him.