What Happens When You Quit Smoking: A Timeline

Quitting does not feel like recovery on day one. It feels like withdrawal. The two run side by side, and knowing which is which makes the first month easier to get through.

The timeline

Two official sources fill the gaps between them. Health Canada gives the main milestones. NHS Wales publishes a more detailed hour-by-hour list, which we use for the early stages and flag as a Welsh source.

When	What changes	Source
20 minutes	Blood pressure and pulse rate return to normal.	NHS Wales
8 hours	The amount of carbon monoxide and nicotine in your blood has halved.	NHS Wales
24 hours	The risk of a heart attack begins to drop.	Health Canada
48 hours	NHS Wales says the body is nicotine free and taste and smell improve.	NHS Wales
72 hours	Breathing is easier and you have more energy.	NHS Wales
2 to 12 weeks	Circulation and lung function improve.	NHS Wales
Within weeks	You breathe more easily and cough less.	Health Canada
3 to 9 months	Less coughing, sinus congestion, tiredness and shortness of breath.	NHS Wales
1 year	Risk of coronary heart disease is half that of someone who smokes.	Health Canada
10 to 15 years	The chance of getting cancer decreases by about half.	Health Canada
13 years or more	Risk of tooth loss is the same as that of someone who has never smoked.	Health Canada

The two sources use different measures at the long end, so read them as approximate. NHS Wales puts the halving of lung cancer risk at 10 years and heart attack risk equal to a never-smoker at 15 years.

What withdrawal looks like

Health Canada says withdrawal symptoms appear within one to two days, peak in the first week and last about 2 to 4 weeks. Trouble falling or staying asleep is a common symptom and, in the department’s words, it will pass. If low mood has not lifted within three weeks of your quit date, Health Canada suggests getting help.

Cravings are covered in their own guide: how long do cigarette cravings last. If the withdrawal is the thing stopping you, nicotine replacement and prescription medication reduce it; see medications to quit smoking in Canada.

What does not come back to normal immediately

Quitting is the most effective way to protect lungs that are already damaged. Health Canada’s COPD page calls it the single most effective intervention in preventing further damage to the lungs, and says respiratory symptoms, most notably a chronic cough, often improve compared with people who keep smoking. It does not promise that lung tissue already lost will grow back.

Health Canada’s page on the risks of smoking puts it this way: most of the risks start to reverse after you quit, sometimes the benefits begin in a matter of hours, and life expectancy improves. The department also says it is never too late to quit.

Keeping count

Counting days helps some people. The smoke-free days counter shows days, cigarettes not smoked and milestones, and the savings calculator turns your habit into dollars. For what the other side of the ledger looks like, read cigarette side effects.