Does running help your lungs recover from smoking?

Running helps your lungs recover from smoking, but not in the way most people think. It doesn't scrub tar out of your lungs or regrow damaged tissue. Quitting does the healing: your airways start clearing mucus within days, and lung function improves over the following months. What running adds is a fitter heart, stronger breathing muscles and muscles that use oxygen better, so the same effort leaves you less out of breath.

There is also evidence that active smokers and ex-smokers have better lung function than inactive ones, and that exercise cuts cigarette cravings while you are quitting. If your lungs are already damaged, exercise won't reverse it, but it is still the main treatment doctors use to make breathing easier.

Does running help your lungs recover from smoking? The short answer

It helps, alongside quitting rather than instead of it. Two different things improve after you stop smoking, and running affects them differently.

Your lungs themselves. The airways, the mucus-clearing system and the inflammation caused by smoke recover because the smoke has stopped. The NHS says your lungs are clearing out mucus after 48 hours, that breathing may feel easier after 72 hours because your bronchial tubes have started to relax, and that after 3 to 9 months "any coughs, wheezing or breathing problems will be improving as your lung function increases by up to 10%." In the Lung Health Study, which followed 3,926 smokers with early COPD, those who quit gained an average of 47 ml (2%) of lung function in the first year. After that their lung function declined at half the rate of people who kept smoking. Running doesn't drive these changes. Not smoking does.

Your breathing capacity. How breathless you feel on a hill depends as much on your heart, blood and muscles as on your lungs. This is where running makes a real difference. The American Lung Association says regular exercise "makes your lungs and heart stronger," that your body "becomes more efficient at getting oxygen into the bloodstream," and that over time you are less likely to get short of breath during exercise.

So running won't undo damage, but it makes the lungs you have work better, and it gives you a way to see your recovery in numbers: your pace, your heart rate and how far you can go before you need to stop.

What the research says about exercise and smokers' lungs

Two large studies have looked at whether physically active smokers have better lungs than inactive ones.

The first, from the Copenhagen City Heart Study, followed 6,790 adults for about ten years. Among people who kept smoking, those with moderate or high levels of physical activity lost lung function more slowly than those with low activity, by 2.6 and 4.8 ml a year respectively. They were also less likely to develop COPD (odds ratio 0.77). The authors concluded that moderate to high regular physical activity is associated with reduced lung function decline and COPD risk among smokers.

The second, the European Community Respiratory Health Survey, followed adults in several countries over ten years. Current smokers who did vigorous leisure-time exercise had higher FEV1 (the amount of air you can blow out in one second) and FVC (the total amount you can blow out) over the ten years than inactive smokers. But this study did not find that exercise slowed the rate of decline.

Put together, active smokers tend to have better lung function, but the evidence that exercise slows the damage is mixed. These are observational studies, so part of the difference may be that people with healthier lungs find it easier to exercise. And neither study suggests exercise cancels out smoking. The Lung Health Study's numbers show what quitting does, and they are larger.

Why running gets easier so soon after quitting

Most people who start running after quitting notice their breathing improving within weeks, long before the lung tissue itself has changed much. A small study shows why.

In a study published in Medicine & Science in Sports & Exercise, 11 young male smokers did exercise tests before and after 6 to 7 days without cigarettes. Their lung function did not improve significantly in that week. Yet they could keep exercising for significantly longer, and the authors concluded that exercise performance improved after 7 days of abstinence.

The likely reason is the blood rather than the lungs. Cigarette smoke contains carbon monoxide, which takes up space on red blood cells that oxygen would otherwise use. Once that clears over the first days, your muscles get more oxygen from every breath. The NHS adds that between 2 and 12 weeks after quitting, blood pumps through to your heart and muscles much better because your circulation has improved.

For a week-by-week view of how pace and endurance change, see our performance timeline for runners who quit smoking.

Does running clear your lungs?

This is one of the most common beliefs about running and smoking, and it isn't right. Your lungs clean themselves. Tiny hair-like structures in the airways move a layer of mucus upwards, and you swallow or cough it out. Smoking slows this down, and it starts working again once you stop. That is the "clearing out mucus" the NHS describes from day two.

Running doesn't speed up that process in any proven way, and it can't pull tar out of lung tissue. What it does do is make you breathe harder, which often brings up mucus in the first weeks after quitting. That can feel like running is "clearing" your lungs. It is your airways doing their normal job, and you would cough it up anyway.

Coughing more after quitting is common and usually temporary. Our guide to why your cough can get worse after quitting explains when it settles and when to get it checked.

If your lungs are already damaged

Long-term smoking can destroy the air sacs deep in the lungs (emphysema) and thicken and narrow the airways. That damage doesn't grow back. The NHLBI says COPD has no cure, but that treatments and lifestyle changes such as quitting smoking can help you feel better, stay more active and slow the disease.

Exercise is a big part of that. Doctors treat COPD with pulmonary rehabilitation, a supervised programme built around exercise training. A Cochrane review of 65 trials with 3,822 people found that it relieves breathlessness and fatigue, improves emotional wellbeing and gives people a stronger sense of control over their condition. On average, people could walk about 44 metres further in six minutes afterwards.

So even when the lungs can't heal fully, training the rest of the body takes pressure off them. The American Lung Association says people with lung disease "can and should get regular exercise," but should work with their healthcare team on a plan. If you get breathless easily, ask your doctor about a referral to pulmonary rehab before you start running on your own.

Running also helps you stay quit

Lungs only recover if you stay off cigarettes, and this is where running may matter most. A 2013 meta-analysis of individual participant data in the journal Addiction concluded that there is "strong evidence that physical activity acutely reduces cigarette craving." A short run or brisk walk when a craving hits is one of the few tools that works within minutes.

Running also gives you a reason not to smoke that you can feel. Every week you go without a cigarette shows up on your watch as an easier pace or a lower heart rate. Our article on how exercise helps you quit smoking goes into the craving research in more detail.

How to start running after you quit

Start slower than you think. In the first couple of weeks you may be coughing, sleeping badly and tired from withdrawal. Run at a pace where you can still hold a conversation, or mix one minute of running with two of walking and build from there.

Aim for the weekly guideline, not a distance. The NHS recommends at least 150 minutes of moderate activity or 75 minutes of vigorous activity a week. Running counts as vigorous, so three 25-minute runs meet it. Brisk walking and cycling count as moderate.

Use runs for cravings. Keep your shoes by the door. When a strong craving hits, ten minutes outside usually takes the edge off it.

Track a few simple numbers. Note your time on a fixed route, or your heart rate at an easy pace, once a week. The changes are often easier to see in numbers than to feel, especially in the first month.

Don't run through warning signs. Some breathlessness is normal when you are unfit. Chest pain is not.

The bottom line

Quitting is what heals your lungs. Running can't regrow damaged tissue or wash out tar, but it trains your heart and muscles to make better use of every breath, it is linked to better lung function in smokers, and it cuts cravings at the moments you most need it. Within a week of stopping, exercise already gets easier, and the gains keep building for months.

If your lungs are already damaged, exercise is still one of the best things you can do, ideally with your doctor's input. Either way, the combination works best: stop smoking, then start moving.