(CBS) — We're reminded every year just how old we are. But could you guess your lung age? Researchers in Britain are targeting smokers with a new tool that tells them exactly how old their lungs are. It's just the incentive some smokers need.

Everybody knows — smoking kills. The warnings are everywhere. They've even kicked people out of their beloved bars and pubs, making them no-smoking zones, all to persuade puffers to quit those butts for good.

But die-hard smokers don't want to hear it.

Lucy Reynolds was up to 60 a day. She was desperate for a baby, even had several miscarriages. Then came the moment.

“I'm going to die,” she said. “That's what I thought.”

Here's what scared Lucy stiff: a machine that told her how "old" her lungs were by measuring their capacity. In her late 30s, her lungs were almost 70.

British researchers found that even heavy smokers were twice as likely to quit when they learned the results of the spirometer.

“The thing that makes it work is that we are giving information in a way that can be understood not only verbally, but graphically,” explained researcher Dr. Gary Parkes.

And even smokers who got a surprisingly good lung score still quit — thinking, “Wow, I just dodged a bullet.”

“It's not me battering them as a health professional or the government battering them with taxes; it's their decision — it puts the ball firmly in their court,” said Parkes.

In short, it's personal, and seeing damage done in black and white can be a big motivator.

“You've got to focus and say, ‘Why am I doing this? I don't want to die; I want to be a fit and healthy person,’” Reynolds said.

She's been smoke-free for three years now, and nobody could be happier for that than Lucy's baby boy.