Heart-Attack Risk Is Substantially Lower
The NHS describes heart-attack risk at about half that of a continuing smoker after one year.

What happens to your body 1 year after quitting smoking
NHS guidance says that after one year, heart-attack risk is about half that of someone who continues to smoke. The CDC describes the risk dropping sharply across the first one to two years and continuing to decline after that. These are population comparisons, not a personal risk score.
Health timelines are population-level guides. Individual recovery varies with smoking history, health and treatment. Review the general guidance from the CDC and NHS.
Frequently asked questions
Is my heart-attack risk now half of a never-smoker's?
No. The NHS comparison is with someone who continues to smoke. Personal risk also depends on age, blood pressure, cholesterol and other factors.
Does cardiovascular risk keep falling?
Yes. The CDC describes coronary heart-disease risk continuing to decline over the longer term.