What happens to your body when you quit smoking? The first changes begin within minutes, and the drop in disease risk plays out over years. According to the World Health Organization (WHO), your heart rate and blood pressure fall within 20 minutes, the carbon monoxide level in your blood returns to normal within 12 hours, and after one year your risk of coronary heart disease is about half that of a smoker's. It takes about 10 years for lung cancer risk to fall to about half, and 15 years for coronary heart disease risk to reach that of a nonsmoker.
This article walks through that quit smoking timeline using pages from the WHO, the US Centers for Disease Control and Prevention (CDC), the UK National Health Service (NHS) and the US National Institutes of Health's Smokefree.gov. The times are group averages, they are not the same for everyone, and nothing here replaces medical advice. The money side of quitting is a separate topic, so we point you to our quit smoking calculator near the end instead of repeating it.
The timeline after your last cigarette
The table below puts the times from three sources side by side. Each cell summarizes what that source says for that point in time. The sources are the WHO question-and-answer page dated 25 February 2020, the CDC page "Benefits of Quitting Smoking", which shows the date May 15, 2024, and two NHS pages that show no date and were read on 28 October 2026. When a source says a risk "drops" or "decreases," CDC states on its page that this means compared with continuing to smoke.
| Time since quitting | What the sources say | Source |
|---|---|---|
| 20 minutes | WHO: heart rate and blood pressure drop. NHS: pulse starts to return to normal. | WHO, NHS |
| 8 to 12 hours | WHO: carbon monoxide in the blood drops to normal at 12 hours. NHS: at 8 hours oxygen levels are recovering and carbon monoxide has halved. | WHO, NHS |
| 24 to 48 hours | CDC: blood nicotine drops to zero at 24 hours. NHS: at 48 hours carbon monoxide is at a nonsmoker's level, the lungs start clearing mucus, and taste and smell improve. | CDC, NHS |
| 2 to 12 weeks | Circulation improves and lung function increases. | WHO, NHS |
| 1 to 9 months | WHO: coughing and shortness of breath decrease. NHS: at 3 to 9 months coughs, wheezing and breathing problems improve and lung function rises by up to 10%. | WHO, NHS |
| 1 year | WHO: risk of coronary heart disease is about half a smoker's. NHS: risk of heart attack has halved. CDC: heart attack risk drops sharply at 1 to 2 years. | WHO, NHS, CDC |
| 5 years | WHO: stroke risk falls to a nonsmoker's level 5 to 15 years after quitting. CDC: at 5 to 10 years the added risk of mouth, throat and voice box cancers halves and stroke risk decreases. | WHO, CDC |
| 10 years | WHO: lung cancer risk falls to about half a smoker's. NHS: risk of death from lung cancer has halved. CDC: added lung cancer risk halves after 10 to 15 years. | WHO, NHS, CDC |
| 15 years | WHO: coronary heart disease risk is that of a nonsmoker's. NHS: heart attack risk is the same as someone who has never smoked. CDC: coronary heart disease risk is close to a nonsmoker's. | WHO, NHS, CDC |
The sources sometimes give the same event at different times, or measure a different outcome. For carbon monoxide the WHO says 12 hours, the NHS says 48 hours and the CDC says several days, and none of the pages explains the gap. For the heart, the WHO gives one year for "coronary heart disease risk," while the CDC gives 3 to 6 years for the "added risk of coronary heart disease." Read the times in the table as ranges that differ between sources, not as exact dates.
The first hours and days
Heart and blood: 20 minutes to 12 hours
All three sources start with the heart. The WHO says heart rate and blood pressure drop within 20 minutes, the CDC says heart rate drops within minutes, and the NHS says your pulse starts to return to normal and suggests you can check it yourself. The pages do not say how large the drop will be for any one person.
At 8 hours the NHS says oxygen levels are recovering and the level of harmful carbon monoxide in your blood has halved. The WHO says the carbon monoxide level is back to normal at 12 hours.
Nicotine, taste and smell: the first 48 hours
The CDC says the nicotine level in your blood drops to zero 24 hours after your last cigarette. By 48 hours the NHS says your lungs are clearing out mucus and your senses of taste and smell are improving. At 72 hours it says breathing may feel easier because your bronchial tubes have started to relax, and that your energy is increasing.
How long do nicotine withdrawal symptoms last?
The good changes arrive at the same time as withdrawal. Smokefree.gov, a US National Institutes of Health site, says the worst nicotine withdrawal symptoms usually last less than two weeks, but that this time can be really tough. The page is undated and was read on 28 October 2026. The NHS adds that after the withdrawal stage, people have reduced anxiety, depression and stress, and that it can take as little as 6 weeks to start feeling the mental health benefits.
Weeks and months: circulation, cough and lungs
The WHO and the NHS both put improved circulation and rising lung function between 2 and 12 weeks. The NHS says better blood flow to the heart and muscles makes physical activity easier.
When the cough fades depends on which page you read. The WHO says coughing and shortness of breath decrease over 1 to 9 months, the CDC says 1 to 12 months, and the NHS says coughs, wheezing and breathing problems improve between 3 and 9 months.
As for how long it takes the lungs to heal after quitting smoking, none of the sources we read gives a day on which that is complete. The NHS says clearing of mucus starts by 48 hours and lung function increases by up to 10% at 3 to 9 months. Giving a date for "fully cleared" would go beyond what these sources state.
Years: heart, stroke and cancer
Heart disease: when does heart attack risk drop?
At one year the WHO says coronary heart disease risk is about half that of a smoker, and the NHS says heart attack risk has halved. The CDC says heart attack risk drops sharply at 1 to 2 years and puts the halving of added coronary heart disease risk at 3 to 6 years. At 15 years all three sources say the risk matches or is close to that of someone who has never smoked.
"Halved" does not mean the risk is gone. The comparison is with someone who keeps smoking.
Stroke and cancer: 5 and 10 years
The WHO says stroke risk falls to a nonsmoker's level 5 to 15 years after quitting. The CDC says the added risk of mouth, throat and voice box cancers halves at 5 to 10 years.
At 10 years the WHO says lung cancer risk is about half a smoker's and that the risk of cancer of the mouth, throat, esophagus, bladder, cervix and pancreas decreases. The NHS says the risk of death from lung cancer has halved. The CDC says the added risk of lung cancer halves after 10 to 15 years.
What the timeline does not show
The table summarizes group data and does not give a personal calendar. Keep these limits in mind:
- The pages give each time as one average. They do not give a personal time based on how long you smoked, how much you smoked per day, your age or your health.
- The sources say people with existing disease also benefit. The CDC says people already diagnosed with coronary heart disease or COPD benefit from quitting. The WHO says people who quit after a heart attack cut their chance of another one by 50% compared with those who keep smoking. The times in the table are not given separately for people with these conditions.
- The table is not a way to diagnose or monitor yourself. If you have shortness of breath or chest pain, talk to a clinician instead of waiting for a milestone to pass.
- Weight and appetite are not on the timeline. The NHS says you might notice things like weight gain or coughing as your body adjusts, without giving a figure. To see your daily energy needs, you can use our basal metabolic rate calculator.
Age is a separate variable. Compared with people who kept smoking, the WHO says people who quit at about 30 gain almost 10 years of life expectancy, at about 40 gain 9 years, at about 50 gain 6 years and at about 60 gain 3 years. The CDC says quitting benefits health at any age, and that quitting earlier brings greater benefits.
The money side of quitting
The health gains take months and years, while the savings start the day you stop. To estimate your daily spending, divide your cigarettes per day by the number in a pack and multiply by the pack price. Here is a hypothetical example: someone who smokes 20 cigarettes a day from packs of 20 at $10 per pack spends $10 a day, or $300 over 30 days. These numbers only show the arithmetic, so use your own prices.
Our quit smoking calculator takes your quit date, cigarettes per day and pack price, and shows the smoke-free time, cigarettes avoided and money saved. It also lists health milestones by quit date, and this article gives those milestones their sources and scope.
Where to get help
In the United States, 1-800-QUIT-NOW (1-800-784-8669) connects you to your state's quitline. Smokefree.gov describes quitlines as free, anonymous telephone counseling services in which you talk to a trained counselor and make a strategy for quitting, and notes that hours and services vary by state. In Turkey, the Ministry of Health runs the ALO 171 Sigara Bırakma Danışma Hattı (Turkish), reached by dialing 171. Phone numbers and services can change, and current details are on the official sites.