According to the American Heart Association and the U.S. Surgeon General, this is how your body starts to recover when you quit smoking:

• In the first 20 minutes: your blood pressure and heart rate recover from the nicotine-induced spikes.
• After 12 hours: the carbon monoxide levels in your blood return to normal.
• After two weeks: your circulation and lung function begin to improve.
• After one to nine months: clear and deeper breathing gradually returns; you have less coughing and shortness of breath; you regain the ability to cough productively instead of hacking, which cleans your lungs and reduce your risk of infection.
• After one year: your risk of coronary heart disease is reduced by 50 percent.
• After 5 years: Your risk of cancer of the mouth, throat, esophagus, and bladder are cut in half. Your risk of cervical cancer and stroke return to normal.
• After 10 years: You are half as likely to die from lung cancer. Your risk of larynx or pancreatic cancer decreases.
• After 15 years: your risk of coronary heart disease is the same as a non-smoker’s.