What happens to your body when you quit smoking

The first day

According to the World Health Organization, heart rate and blood pressure drop within 20 minutes of the last cigarette, and the carbon monoxide level in the blood drops to normal within 12 hours. The US CDC and the American Cancer Society give a wider range of 24 hours to a few days for carbon monoxide; either way it happens fast.

The first weeks

Within days to weeks, the NHS says taste, smell, breathing and energy start to improve. Between 2 and 12 weeks, the WHO describes better circulation and lung function.

Many people are surprised to cough more at first. The tiny hairs that clean the airways start working again and clear what has built up, and the WHO describes coughing and shortness of breath decreasing over 1 to 9 months.

The first years

These are the long term changes reported by the WHO, CDC and NHS:

• 1 year: the risk of coronary heart disease is about half that of a smoker (WHO, NHS).
• 5 to 15 years: the risk of stroke falls to that of a non-smoker (WHO).
• 10 years: the risk of dying from lung cancer is about half that of a smoker (WHO, NHS).
• 15 years: the risk of coronary heart disease is that of a non-smoker (WHO, CDC).

How Freewill uses this

Freewill turns this timeline into nineteen milestones and tells you when each one is reached, from the first hours to day 45 and beyond, next to your smoke-free time, money saved and cigarettes not smoked.