What Happens to Your Body After You Quit Smoking

Eli Hendel, M.D. | July 27, 2017

Reviewed by Eli Hendel, M.D.

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Quitting smoking is incredibly difficult. Cigarettes are addictive, so the amount of control necessary to battle the cravings, especially in the early days, weeks, and months, can be overwhelming. But the benefits to your health occur sooner than you might think, regardless of how many cigarettes you puff daily or how long you’ve smoked.

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How much do you smoke?

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Your pack-year history is calculated by multiplying the number of packs of cigarettes you smoke daily by the number of years you’ve smoked. One pack year is equivalent to smoking one pack of cigarettes (20 cigarettes) daily for one year. Whether you smoke two packs a day for 10 years or one pack a day for 20 years, the pack history in both cases is 10 pack years.

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Some of the benefits of quitting smoking

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When you give up smoking you lower your risk of developing cancer, heart disease, and lung diseases, such as emphysema and bronchitis. Smoking can affect oral health, men’s sperm health, and is a risk factor for rheumatoid arthritis. It also can make it harder for a woman to become pregnant or can hurt a growing fetus. But the benefits of quitting can begin as quickly as one hour after you stub out that last cigarette. Here’s what happens in the hours, weeks, and months after quitting.

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12 hours after you quit smoking

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Carbon monoxide, a harmful gas, is present in cigarette smoke, and it prevents oxygen from entering your blood and your lungs. Just 12 hours after you stop smoking, your levels of carbon monoxide are reduced and return to normal, allowing oxygen levels to increase.

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1 day after you quit smoking

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Smoking raises blood pressure because it constricts blood vessels. It also increases the risk of developing coronary heart disease because it lowers HDL, the good cholesterol. Smoking raises the risk of blood clots, which increases the risk of a heart attack or stroke. Research shows that one day after you quit smoking your blood pressure will decrease and your oxygen levels will increase, which will make exercise efforts easier.

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48 hours after you quit smoking

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Much like after being two days into a diet, you may feel more in control. Because smoking damages the nerves that help you smell and taste, you may begin to experience the flavor of food better and to smell more odors. Your nerves are healing.

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72 hours after you quit smoking

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At this point your body is beginning to feel a diminished level of nicotine. This is a good thing, but nicotine withdrawal can cause symptoms such as moodiness, irritability, headaches, and cravings. You might need to consider using an over-the-counter nicotine replacement product, such as a skin patch, chewing gum, or lozenges if your symptoms are significant.

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30 days after you quit smoking

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Not smoking for a full month is a big deal. My patients often tell me that their coughing has decreased and they feel like they are breathing better. That’s because the lungs are beginning to heal at this point. You may notice less shortness of breath, especially on exertion. You can begin a running program and feel less compromised because oxygenation is so much better. Over the next three months, you will continue to enjoy those health improvements.

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9 months after you quit smoking

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Cilia in the lungs are small hairlike structures that help to push out mucus. They also help in the fight against respiratory infections. At this point the cilia are significantly healed and more functional because daily smoke is no longer invading your lungs. You may notice you’re experiencing fewer respiratory infections.

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1 year after you quit smoking

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This is a huge milestone. Typically your heart health profile is significantly improved and your risk of coronary heart disease is cut by half. Heart attack risk and stroke risk are significantly lowered. Those improvements will continue as long as you don’t smoke. From my experience, if you can make it to year five, it’s likely you will have quit smoking for good.

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10 to 15 years after you quit smoking

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After 10 years your risk of lung cancer will be reduced by 50 percent. Mouth, throat, and pancreatic cancer risks are also significantly decreased. If you make it to 15 years without smoking, your risk of developing coronary heart disease is now equal to that of a nonsmoker. I tell my patients that they really can heal their body when they give up a habit like smoking. The promise of a new lease on life can be incredibly persuasive.