A Timeline of the Effects of Quitting Smoking

According to the US Centers for Disease Control, stop smoking benefits begin shortly after you stub our your last cigarette, and progressively increase for years.
(Bear in mind that these are statistical averages, and you may experience them on a different timescale.
) 20 Minutes Twenty minutes is all it takes after your last cigarette for your heart rate (and blood pressure) to drop.
Nicotine activates your stress response and puts strain on your heart.
By stopping smoking, you remove that strain.
12 Hours After 12 hours, the level of carbon monoxide in your blood returns to normal.
Carbon monoxide is the gas that people who commit suicide by inhaling car exhaust fumes are using to kill themselves.
It takes the place of oxygen on your red blood cells and prevents them from carrying it around your body.
2 Weeks to 3 Months About 14 to 90 days after you quit smoking, your body recovers enough that your heart attack risk starts to drop and your lung function starts to improve.
1 to 9 Months Between a month and 9 months after giving up smoking, coughing and shortness of breath should start to decrease.
1 Year Celebrate your quit-smoking anniversary, in the knowledge that your added risk of coronary heart disease is now half that of someone who's continued to smoke.
(It's not back to the level of someone who's never smoked yet, though - that'll take another 9 years.
) 5-15 Years After between 5 and 15 years of being smoke-free, your risk of stroke (catastrophic failure of the blood supply in your brain) is down to the level of a lifetime nonsmoker.
10 Years The death rate from lung cancer of people who have been non-smokers for 10 years is about half that of current smokers.
Your risk of other cancers (mouth, throat, esophagus, bladder, kidney, and pancreas) also decreases.
15 Years Fifteen years after you quit smoking, your risk of coronary heart disease has returned to what it would be if you had never smoked.
Again, these are statistical averages, and you're not, so your experience may differ.
The important point to take away from this timeline of the effects of quitting smoking is that the sooner you stop smoking the sooner you'll experience the health benefits and reduce your risk of serious illness.
If you only feel able to do one thing to improve your health, quitting smoking is the one to pick, as it has the greatest positive impact on your health and wellbeing.