'Deadliest Catch' 's Sig Hansen Reveals How He's Changing His Life After a Massive Heart Attack

He thought it was just heartburn.

“It was sharp and radiated from my chest up through my neck,” Sig Hansen tells PEOPLE in this week’s issue about the crippling pain he experienced last February while sitting in the captain’s chair of his fishing boat.

Known to Deadliest Catch fans as the tough-as-nails captain of the Northwestern, Hansen, 50, had an easy solution.

“I wanted to take a bunch of Advil and Tums and make it go away and lie down,” he says.

But it wasn’t heartburn – it was a heart attack.

“Had I gone to sleep,” says Hansen. “I’d probably be dead.”

[IMAGE “2” “” “std” ]Convinced by both his fishing boat crew and the Deadliest Catch producer who was shooting footage for the show’s 12th season finale – which PEOPLE has an exclusive preview clip of above – when the heart attack symptoms first presented, Hansen rushed his boat to the nearest Alaskan port and was soon airlifted to a hospital in Anchorage.

• For more from Sig Hansen – including the devastating depression and medicinal side effects he’s faced since his heart attack – pick up this week’s issue of PEOPLE, on newsstands now

“The doctor said I’d had a 50-50 chance of surviving,” says Hansen, who had suffered a stress-induced heart failure also known as a widow-maker. “It made me realize that I’ve always put my job first,” he says. “Now it’s time to be here for my family. I’m changing my life so I can be here for them.”

Now, Hansen has embraced a healthy new lifestyle.

His Fitbit activity tracker is his “new best friend,” and he’s traded movie nights with potato chips and milkshakes for vegetables and swimming in the pool with his wife at their Seattle home.

“Before, he wouldn’t go with me to walk the dog,” says June. “Now we’re doing so much together.”

The threat of another major heart attack will always be in the back of his mind.

“Every night before I go to bed, I think, ‘Is this it?’ June can’t sleep for the same reason,” says Hansen.

But he’s also appreciating his home life more than ever. Though he’s not retiring, he’s in no rush to head back out to sea.

“I want more family time,” he says. “I got a second chance – a lot of guys don’t. I don’t take life for granted anymore.”

Hansen’s hospitalization will be shown on the two-part season 12 finale of Deadliest Catch, beginning tonight on Discovery Channel at 8 p.m. ET. A special following Hansen’s road to recovery will air on the channel later this year.