For cigarette addicts, it’s only a matter of time before the unhealthy habit stiffens arteries. In fact, the arteries of smokers aged twice as fast as nonsmokers—which increases the chances of blockages that could trigger heart attacks, strokes and other problems, according to study results published online in the Journal of the American College of Cardiology and reported by HealthDay News.

For the study, researchers at Tokyo Medical University measured the speed of blood flow through the arteries of more than 2,000 Japanese adults during a five- to six-year period.

Scientists found that smokers experienced double the amount of stiffening in their large- and medium-sized arteries compared with nonsmokers. (The stiffer the artery, the slower the blood flows through it.)

“This shows that smoking accelerates the process,” said William B. Borden, MD, a preventive cardiologist and assistant professor of medicine at New York City’s Weill Cornell Medical Center. “But it also adds more information in terms of the role smoking plays as a cause of cardiovascular disease.”

The more people puffed away, the more they damaged their arteries, Borden added, explaining that these negative effects were often subtle and long-term.

Often when doctors try to convince people to quit, the smokers counter that they’ve smoked for years without a major health problem, said David Vorchheimer, MD, an associate professor of medicine and cardiology at New York City’s Mount Sinai Medical Center.

“What this study emphasizes is that the damage is cumulative,” Vorchheimer said. “The fact that you’ve gotten away with it so far doesn’t mean you’ll get away with it forever.”

According to the article, the good thing about quitting is the possibility that the damage will heal, Vorchheimer stressed.

Click here to learn more about the unhealthy effects of cigarette smoking.