Within 20 minutes Blood pressure and pulse return to normal
Within 8 hours Circulation improves and oxygen levels in the blood return to normal
Within 24 hours Carbon monoxide is eliminated from the body
Within 3 to 9 months Breathing problems show improvement with lung function increased by 5% to 10%
Within 5 years Risk of heart attack falls to about half that of a smoker
Within 10 years Risk of lung cancer falls to half that of a smoker
Within 10 years Risk of heart attack similar to someone who has never smoked Source : National Asthma and Respiratory Training Centre 1999