EASTCHESTER, N.Y. (CBSNewYork) — A Westchester County man says he’s thankful to be alive after an app on his Apple Watch sent out an alert that he was having a critical health emergency.

Doctors at Greenwich Hospital told Nancy Monzidelis that had she not immediately gotten him the help he needed , her son William would have been dead in an hour or two.

William was working at their family business, Bowlerland Lanes in Eastchester, a month ago when he passed blood in the bathroom. He says his latest model Apple Watch started going off almost instantly.

“I was getting notifications from my watch telling me that I needed to seek medical attention immediately, my heart rate is going too high and too low, numbers that I’ve never had in my life,” William said.

Then, his mother came over to check on him and noticed he didn’t look right.

“I looked at his lips, they’re always pink like lipstick. ‘Your lips are white and blue, what’s going on?’. He said, ‘maybe I bled too much, my lips are never white and blue’,” Nancy said.

Nancy had heard enough. They piled into her car and sped to the hospital, but William was crashing.

“When we got off the exit he started seizing, shaking his head, started projectile vomiting blood out of his mouth, his nose, wherever, then he passed out,” Nancy said. “His eyes rolled back and he was out.”

It turns out, William had a perforated stomach ulcer that was hemorrhaging blood. The notification from the Apple Watch got him to help just in time.

The watch is probably the best known of a new generation of medical sensing devices and apps for iPhones and Android devices. There are tens of thousands of medical apps, with some that may seem like novelties or of limited value.

That’s not how William sees it.

“I owe my life to that company, literally owe my life,” he said. “If I didn’t see that I would have gone back to my office, probably passed out, and that would have been it.”

It took a blood transfusion and an emergency endoscopy to cauterize the ulcer and stop the bleeding. It’s been a month since the crisis, and William says he’s getting his energy back by taking iron pills and eating red meat to help replace the nearly half of his blood volume he had lost.