With nicotine said to be more addictive than heroin, quitting cold turkey is a tough call for many smokers. Without help, fewer than 7 percent manage it; but with assistance from antismoking programs, success rates more than quadruple (PDF), according to a report from the American College of Physicians.

"No matter how you cut it, quitting does take commitment and hard work," says Fiore, who describes tobacco dependence as a chronic disease. No doctor would tell you to control diabetes or high blood pressure just by using willpower, he adds. "Similarly, you want to take advantage of all the medical tools — medications and counseling — that can enhance the likelihood that you'll successfully quit."

What about older Americans who have been smoking for 30, 40 or 50 years and feel that it's too late for them — that the damage is already done? In fact, Fiore says, research shows that quitting is especially beneficial for them, and not just because they'll be able to climb the stairs without gasping for breath: "Your risk of heart attack will decline 50 percent within one year of quitting. Your risk of cancer within five years of quitting will begin to approach that of a person who's never smoked. If you quit at age 50, your risk of dying in the next 15 years is cut in half. So it's never too late to quit."

Nov. 17 is the 36th Great American Smokeout, an annual event sponsored by the American Cancer Society to encourage smokers to stop for at least one day in the hope that they'll continue permanently. To mark the event, the Society for Vascular Surgery issued a checklist of what would happen to smokers by Nov. 19, only 48 hours after quitting:

• Blood pressure will decrease.

• Pulse rate will drop.

• Body temperature of hands and feet will increase.

• Carbon monoxide level in the blood will return to normal.

• Chance of a heart attack will decrease.

• Nerve endings will start to regrow.

• Ability to taste and smell will increase.

Patricia Barry is a senior editor with the AARP Bulletin.