A new study finds that one year after quitting smoking, the blood vessels of one-time smokers are significantly relaxed compared to their former state, which indicates better blood flow and overall heart health. The findings are published in the March 15 online issue of Journal of the American College of Cardiology.

The study is the first of its kind – a randomized, clinical trial, comparing the function of the brachial artery both before and after patients quit smoking. The researchers, led by James Stein, followed 1,500 participants who enrolled in a quit-smoking program at the University of Wisconsin Center for Tobacco Research and Intervention. To monitor the health of the patients’ blood vessels, the researchers measured the flow-mediated dilation, or FMD, of the brachial artery. This test measures how well the artery dilates in response to increased blood flow, and is known to be a strong indicator of heart health.

A 1% change in FMD is 'statistically significant, but more important, it's also clinically relevant. A 1% percent change in FMD is associated with an approximately 14 percent lower rate of cardiovascular disease events.

The researchers found that one year after quitting smoking, the participants’ blood vessels had relaxed considerably, compared to people who started smoking again. Stein says that, “[i]ndividuals who quit smoking had improved blood vessel function, even though they gained weight, which is a common side effect of smoking cessation. This confirms that quitting smoking is good for your blood vessels and reduces risk for heart attacks and cardiovascular disease."

How much did FMD improve for the non-smokers? About 1%, the researchers reported. Though it may not sound like a big change, Stein says that it’s actually a significant reduction, particularly when you consider how it relates to one’s risk of heart disease. Stein says that the 1% change in FMD is “statistically significant, but more important, it's also clinically relevant. A 1% percent change in FMD is associated with an approximately 14 percent lower rate of cardiovascular disease events. That means patients who permanently quit smoking are less likely to have a heart attack and heart disease."

The study may offer new incentive to those who are considering quitting smoking.

The study was conducted by researchers at the University of Wisconsin School of Medicine and Public Health and the University of Wisconsin Center for Tobacco Research and Intervention.