A Timeline of What Happens After You Quit Smoking

The first 24 hours 

Within just 12 hours of quitting smoking, your body starts to experience significant improvements. The carbon monoxide levels in your blood drop back to normal, allowing oxygen to flow more easily. This is a major first step because smoking introduces harmful gases which reduce the oxygen-carrying capacity of your blood. With oxygen levels restored, your organs—including your lungs— function better. 

1-2 days after quitting: cilia begin to recover 

Within the first one to two days of quitting, the tiny hair-like structures in your lungs, called cilia, start to reactivate. These structures play a crucial role in keeping your airways clear. They work by sweeping mucus and debris out of your lungs, preventing infections, and improving your overall respiratory health. 

When you smoke, the harmful chemicals damage or paralyze the cilia, making it hard for your lungs to clear out mucus and toxins. This leads to increased mucus production, chronic cough, and a higher risk of infections. After quitting, the cilia begin to heal and resume their normal function, which improves mucus clearance. You may notice yourself coughing more during this phase as your body works to rid itself of the built-up mucus, but this is actually a sign of healing. 

1 week after quitting: breathing feels easier 

By the end of the first week, many people notice that their breathing becomes easier. This is largely due to the improving function of your cilia and the reduction in mucus production. The inflammation in your airways also begins to decrease, which allows more air to flow in and out of your lungs. You might find physical activities—like walking up stairs or exercising—are less tiring because your lungs are starting to regain their strength. 

1-3 months after quitting: lung function improves 

As you continue to stay smoke-free for a few months, the recovery of your lungs becomes even more noticeable. Between one to three months after quitting, your lung function can increase by as much as 30%.  

During this period, the cilia are nearly fully restored, and their ability to clear mucus is much improved. This reduces the risk of lung infections, such as pneumonia and bronchitis. You may also notice that your chronic cough, if you had one, begins to decrease significantly. 

6 months after quitting: improved mucus clearance and less shortness of breath 

Around the six-month mark, your lungs have made major strides in recovery. The cilia are working efficiently, mucus clearance has normalized, and the inflammation that affected your airways is greatly reduced. Shortness of breath, once a constant companion for many smokers, becomes much less frequent. 

This improvement in breathing makes daily activities easier and significantly lowers your risk of developing chronic lung diseases like chronic obstructive pulmonary disease (COPD). Your body is also better equipped to fight infections, meaning fewer colds and respiratory illnesses. 

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1 year after quitting: risk of heart disease and lung cancer drops 

One year after quitting, your lung function continues to improve. At this stage, your risk for heart disease has dropped by half compared to when you were smoking. The lungs are not fully healed yet, but they have made considerable progress in clearing toxins and rebuilding healthy tissue. Importantly, the cilia function almost as well as in a non-smoker, greatly improving your respiratory health and overall quality of life. 

Long-term recovery: 5-10 years after quitting 

Five years after quitting, your risk of developing smoking-related lung diseases, such as lung cancer and COPD, and supplemental oxygen dependence has significantly decreased. By 10 years, your risk of lung cancer is cut in half, and your lungs will have healed to the point where they function almost like those of a non-smoker. Although some damage caused by years of smoking may be permanent, quitting drastically reduces the chances of further harm and prolongs your life. 

Low-dose CT (LDCT) lung cancer screening: a vital step for long-term health 

In addition to quitting smoking, another important step for those at high risk of lung cancer is getting a low-dose CT (LDCT) lung cancer screening. This is particularly recommended for individuals aged 50 to 80 who have smoked at least one pack a day for 20 years or more.  

The benefit of LDCT is that it can detect lung cancer early—before symptoms appear. Early detection allows for timely treatment, which significantly improves survival rates. In fact, studies show that LDCT can reduce lung cancer deaths by 20% in those at high risk by identifying cancer early when it is most treatable and often curable. 

If you have a long history of smoking, even after quitting, an LDCT scan could be a powerful tool to help protect your lung health. Catching cancer early through screening gives you a much better chance at successful treatment and long-term survival. 

Your lungs have an amazing ability to heal after quitting smoking 

The lungs are one of the most resilient organs in the body, capable of healing themselves when given the chance. If you quit smoking today, your lungs will immediately start the recovery process, and you’ll begin to feel the benefits in just a few days. With every week and month that passes, your lungs will get stronger, breathing will become easier, and your risk for smoking-related diseases will plummet. 

Couple quitting with regular screenings like LDCT, and you’re giving your lungs—and yourself—the best possible chance at long-term health. Your lungs will thank you for every smoke-free day, giving you the chance to enjoy better health, improved breathing, and a longer life. 

By: Dr. Mark Pohlman of Foundation Pulmonary

Dr. Mark Pohlman is fellowship-trained and board-certified in internal medicine, pulmonary medicine, critical care medicine, and sleep medicine. He practices at Foundation Pulmonary.