For surfers, the ocean is a powerful magnet that keeps luring them back.

That’s certainly the case with 68-year-old Ron Greene. Four times over the past 14 years, Greene has suffered heart attacks while surfing. Yet, he keeps surfing.

“Maybe I’m an idiot. Maybe I’m a fool,” the affable Greene said. “I just want to keep living and enjoying it. There is an immensely good feeling after surfing. … I force myself to go out there sometimes just for the exercise and the feeling afterwards.

“Believe me, now that I’m older, I don’t like surfing crap. I like to go out when the conditions are nice. But sometimes, you just have to go.”

Greene, who has owned a San Diego auto storage business for 45 years, can recount his heart attacks with little emotion and great clarity.

He suffered his first at age 54.

“I got there with friends and I wasn’t feeling too good,” Greene said. “I paddle out and there’s a nice little set, and then — boom! — it’s like an elephant is sitting on your chest. It’s super-painful.”

Greene managed to paddle to shore, called his doctor and drove himself to the hospital. He went into surgery the next day to receive seven stents. On the table, he said, he suffered cardiac arrest.

“I’m waking up, and they’re asking me to cough,” he said. “I look forward, and they’ve got these orange pads on my chest. They said, ‘We had to defib you back. Your heart stopped.’ ”

‘He was bluish-gray’

Greene went seven years without any issues. Then in February 2011, he was surfing and felt a similar pain to the first time. Again, he drove himself to the hospital, where he received his eighth stent.

The next crisis would be far more serious and frightening. Greene was competing in a surfing contest — he had reached the semifinals — and was in the water waiting for his next ride when a heart attack came without any warning.

“No pain. No discomfort. Nothing,” Greene said.

He fell into the water, and the surfers around him didn’t realize what was happening. Beyond suffering the heart attack, he was drowning. A friend who was watching from the pier began screaming at lifeguards for help, and they raced out to get him.

“He was bluish-gray. I was thinking he was gone,” said the friend, Celia Hoffman. “It was just horrifying to see this very fit, healthy man [in that state]. It was shocking to me.”

The lifeguards worked frantically, first having to clear water from Greene’s lungs. They used a defibrillator to restart his heart.

“They were working on him, and I’m telling him, ‘Hang on, Ron, you’ve got this. You’re not going anywhere,’ ” Hoffman said. “Then I heard them say that they had a heartbeat and he was responding. I knew he was going to be fine. He’s just too much of a stubborn fighter. He’s not a crotchety old man, but he doesn’t take any BS from anybody.”

At the hospital, he underwent quadruple bypass surgery. “The thoracic surgeon who had my heart in his hand said, ‘You have a very strong heart, but your plumbing is bad. We’re going to fix that and you’re going to be back doing what you’re doing,’ ” Greene said.

He was back in the water two months later — a month ahead of doctor’s orders.

His most recent heart attack came last December. He’d been off his blood-thinning medication for several days as part of an upcoming medical test. He was in the water, felt some discomfort in his chest and made his way to the beach. This time, he didn’t drive himself, but had a lifeguard call paramedics.

Greene got two more stents at the hospital. Now he has 10.

Urging checkups

In speaking about his trauma, he hopes to prod others into getting checkups.

“I have surfer friends who never go to the doctor,” Greene said. “If you get it checked early and they find something, they can fix it. If we can save some people, that’s what it’s all about.”

Greene’s family and friends marvel at his love of surfing, but they can’t ever completely block out that he’s had four heart attacks in the water.

Asked to consider the possibility of another emergency for Greene, Hoffman chuckled and said, “I’ve told him, if he does, I’m walking out. Our friendship is over.”