Chances are the young man that stepped out of your favorite coffee house for a smoke just now has tried to quit at some point. Who knows why his efforts didn't stick? It may have been that he, like most smokers who tried quitting in the last year, didn't get the support he needed. It may have been that he didn't use recommended methods. But what if he knew that if he put out his cigarette right now, in only 20 minutes he'd be enjoying better health?

More than one in five U.S. adults is a smoker. In 2009, that was more than 46 million people, according to the Centers for Disease Control and Prevention (CDC). Of that group, 39.8 percent tried to quit in the past year, but only 10 to 20 percent of them are successful three months later, says Len Lichtenfeld, M.D., deputy chief medical officer of the American Cancer Society.

And yet the younger you are when you stop smoking, the lower your rate of premature death. "The one best thing smokers can do for their health is stop smoking," says Lichtenfeld. "You have to look at the effects of cigarette smoking over time. If you are young, and you stop smoking, you can reduce your risk of cancer in your life." But no matter what your age, the health perks of quitting smoking are immediate as well as long-term. Here's a timeline detailing the benefits:

The quit-smoking health benefits after 20 minutes to 3 months

In the time it takes you to read the morning paper, your health can improve significantly when you stop smoking. "The overall health impact on the heart when you quit is dramatic and fairly quick," says Lichtenfeld. It takes just 20 minutes for your heart rate and blood pressure to drop, and less than a day for the carbon monoxide poisoning in your body that comes from cigarettes to dissipate.

After three months, your circulation will improve and your lungs will be working more efficiently. "When you smoke, there is an immediate reaction to your heart rate and blood pressure," says Lichtenfeld. "Lung function gets better within two weeks to three months after you stop quitting, but the improvements to the heart can be immediate. Smoking puts toxins in your body that affect the way the heart works, the blood vessels work, the organs work. And when you remove that toxin, that allows the body to start healing right away."

  • 20 minutes after quitting: Your heart rate and blood pressure will drop.
  • 12 hours after quitting: The carbon monoxide level in your blood falls to normal.
  • 2 weeks to 3 months after quitting: Your circulation and lung function improve.

The quit-smoking health benefits after 9 months to 1 year

In the same time it would take a pregnant woman to carry a baby to term, or for you to celebrate one birthday and then another, you'll notice an improvement in the overall health of your lungs. You'll also notice improvement in heart function, and perhaps also in your ability to enjoy food.

By nine months most people notice a decrease in coughing and easier breathing. Sometimes these changes can happen in as short a time as a couple of months. Lichtenfeld says the cold symptoms smokers seem to always have will frequently subside. This happens because the hair-like cilia in the lungs, which help remove mucus, regain function. Clearer lungs mean your risk of getting an infection is reduced.

Depending on how long you smoked before quitting, you may not be able to reverse some of the damage you've done to your lungs, but you can improve their overall health in other ways. "Once chronic emphysema happens—a disease in the lung where the air sacks in the lung scar and break down in a heavy smoker over time—it is not reversible," says Lichtenfeld. "But what can happen in some people is that the inflammation, the bronchitis, the coughing and the sputum, can stop."

After one year, your heart rate and blood pressure will have decreased, lowering your overall risk of heart disease. If heart damage has already occurred, you won't be able to reverse it, but you will be able to improve your overall health. "The mechanisms in the body that can cause a heart attack due to smoking are certainly much less at one year after quitting," says Lichtenfeld. "A heart attack is a dynamic process that happens when many factors combine. If you don't smoke, [do] eat a healthy diet [and] keep your blood pressure under control, you may significantly lower the risk of having a heart attack."

At this point, the senses of taste and smell may also improve, says Lichtenfeld. "People don't expect it, but when you talk to former smokers, one of the things they notice and appreciate is that they can actually taste their food again." Lichtenfeld cautions that some people who stop smoking gain weight because they aren't relying on cigarettes to curb their appetite. He suggests having an eating plan in place when you quit. "I'd rather people realize that and deal with the appetite issue, [rather] than deal with the bad effects of smoking," he says.

  • 9 months after quitting: Coughing and shortness of breath are reduced.
  • 1 year after quitting: Your risk of coronary heart disease is reduced to half of what it was when you smoked.

The quit-smoking health benefits after 5 to 15 years

If you've managed to stay clean of cigarettes for the same amount of time it takes to raise a child until he or she enters kindergarten, then you've decreased your risk of heart disease and stroke almost to the same level as if you'd never smoked. You've also significantly decreased your risk of lung cancer.

Smokers are at increased risk for 15 types of cancer, including that of the lung, esophagus, stomach, bladder, kidney, pancreas and cervix, says Lichtenfeld. After 5 to 15 years, your risk of getting many of these cancers decreases significantly. "When you take away those chemicals that cause cancer, the risk of getting cancer is [lessened]," says Lichtenfeld. Your risk of lung cancer can be reduced, but never completely eliminated, if you've smoked. "Lung cancer is a serious issue," he says. "People who are heavy smokers over a long time, when they stop, the risk of lung cancer does not go away." However, your chance of getting a stroke does improve dramatically. "The risk of stroke decreases 5 to 15 years after people stop smoking," he says.

So if you’re thinking of quitting, or feeling vulnerable to starting again, take a breather, fix some breakfast, call a friend for a chat. In the time it took you to do either, you've already improved your health. A study by the British Medical Journal reported that individuals lose 11 minutes of their life for every cigarette smoked. So, sit back, do the math, and appreciate the number of 11-minute segments you've gained by quitting, whether 20 minutes ago, one year ago, five or 15 years ago.

  • 5 years after quitting: Your risk of stroke is the same as if you had never smoked.
  • 10 years after quitting: Your chances of dying from lung cancer are now half of what it would have been had you continued to smoke. Your risk of getting cancer of the mouth, throat, esophagus, bladder, cervix, and pancreas has also decreased.
  • 15 years after quitting: Your risk of coronary heart disease is the same as if you'd never smoked.