The Great American Smokeout is helping Americans kick the habit.

American Cancer Society spokesman Robin Brown says the annual event helps smokers take an important step toward a healthier life.

The smokeout, which is celebrated on the third Thursday of November, encourages people to quit smoking by giving them a date to stop. The Cancer Society also has a number of resources on their website to help smokers quit for good.

Brown says the number of smokers in the country is dropping, but more than 43 million Americans still smoke cigarettes. Tobacco use is still the largest preventable cause of disease and premature death in the U.S.

As the smokeout encourages Americans to quit smoking today, doctors are reminding people that the positive effects of quitting can be seen almost immediately. Heart rate variability goes up within at least 15 minutes after you stop smoking. Blood pressure, circulation and lung function also improve. After a year of no smoking, the risk of having a heart attack is half of that of someone who smokes.

[Metro Networks]