What happens to your body when you quit

Twenty minutes after your last cigarette, your heart rate drops. Twelve hours later, carbon monoxide levels in your blood normalize. Twenty-four hours in, your heart attack risk begins to fall. The timeline tracks these milestones so you can see exactly where you are — and what comes next.

The numbers are not promises. They are probabilities, drawn from population-level research. Your individual recovery will vary based on how long you smoked, how heavily, and your baseline health. But the direction is always the same: forward.