What Happens to Your Body When You Quit Smoking — Hour by Hour

One of the most motivating things about quitting smoking is how fast your body starts to recover. The damage from smoking is severe, but the human body is remarkably good at healing itself once you stop poisoning it.

Here's what happens, hour by hour and year by year.

The First 72 Hours

20 minutes: Your heart rate drops. Blood pressure begins returning to normal. Your hands and feet get warmer as peripheral circulation improves. This is the first measurable sign that quitting is already working.

8 hours: Carbon monoxide levels in your blood drop by half. Carbon monoxide from cigarette smoke binds to hemoglobin 200 times more effectively than oxygen — when you smoke, up to 15% of your blood carries CO instead of O2. After 8 hours, your blood is carrying significantly more oxygen to your brain, muscles, and organs.

24 hours: Your risk of heart attack begins to decrease. Smoking raises heart attack risk by promoting blood clots, narrowing arteries, and increasing blood pressure. Within one day, your cardiovascular system starts to stabilize.

48 hours: Nerve endings begin to regrow. This is when many ex-smokers first notice food tastes better and smells are more vivid. The chemicals in cigarette smoke damage taste buds and olfactory receptors — once you stop exposing them to toxins, they regenerate.

72 hours: Nicotine is completely eliminated from your body. Your bronchial tubes relax, making breathing easier. Energy levels increase. This is also when withdrawal peaks — but knowing this is the hardest point can help you push through. After 72 hours, the physical addiction is breaking.

The First Year

2 weeks: Circulation improves significantly. Walking, climbing stairs, and exercise become noticeably easier. Lung function may have improved by up to 30%.

1 month: Lung cilia — tiny hair-like structures that sweep debris from your airways — begin to regrow. Smoking destroys them, which is why smokers are prone to respiratory infections. You might cough more temporarily as your lungs clear accumulated tar. This is a sign of healing.

3 months: Lung function has improved by up to 30%. Heart disease risk has dropped considerably. Many people notice they get sick less often.

6 months: The persistent cough has resolved. Shortness of breath during normal activities has decreased dramatically. Lung cilia are fully restored.

1 year: Your risk of coronary heart disease is now half that of a smoker. This is a landmark milestone — heart disease is the leading cause of smoking-related death, and you've cut your excess risk in half.

The Long Term

5 years: Stroke risk drops to the same level as someone who has never smoked. The blood vessels that smoking damaged have healed and become more flexible.

10 years: Your risk of dying from lung cancer is roughly half that of a continuing smoker. Precancerous cells have been replaced by healthy tissue. Risk of mouth, throat, esophagus, bladder, kidney, and pancreatic cancer also decreases substantially.

15 years: Full cardiovascular recovery. Your risk of heart disease is the same as someone who has never smoked a single cigarette. The years of healing have returned your arteries, blood vessels, and heart to a near-normal state.

The Bottom Line

Every hour without a cigarette is an hour of healing. The first 72 hours are the hardest — that's when nicotine leaves your body and withdrawal peaks. But even during those hours, your body is already recovering. And by the time you hit 1 year, you've cut your risk of the number one smoking-related killer in half.

The best time to quit was years ago. The second best time is today.