Sources for the health milestones

The 14 health milestones the app shows, in order of timing. Each one carries its text exactly as it appears in the app and a direct link to the page of its source.

Milestones count from your last cigarette. If you’re cutting down, the app shows them as what’s ahead once you reach zero.

1. 20 minutesYour heart rate and blood pressure drop.Source: WHO
2. 8 hoursThe carbon monoxide in your blood drops by half and your oxygen level recovers.Source: NHS
3. 12 hoursThe carbon monoxide level in your blood returns to normal.Source: WHO
4. 24 hoursNicotine is no longer in your blood.Source: CDC
5. 48 hoursCarbon monoxide is at a non-smoker’s level, and your taste and smell improve.Source: NHS
6. 72 hoursYour airways relax, breathing gets easier, and your energy goes up.Source: NHS
7. 2 to 12 weeksYour circulation improves and your lung function increases.Source: WHO
8. 28 daysPeople who reach 28 days smoke-free are much more likely to quit for good.Source: NHS
9. 1 to 9 monthsCoughing and shortness of breath decrease.Source: WHO
10. 3 to 9 monthsYour lung function improves by up to 10%.Source: NHS
11. 1 yearYour risk of coronary heart disease is about half that of a smoker.Source: WHO
12. 5 yearsYour risk of stroke falls to that of a non-smoker 5 to 15 years after quitting.Source: WHO
13. 10 yearsYour risk of lung cancer falls to about half that of a smoker.Source: WHO
14. 15 yearsYour risk of coronary heart disease is that of a non-smoker.Source: WHO

Sources checked on October 5, 2026.