Yes, humans can live with one lung, and many do. The medical procedure for removing a lung is called pneumonectomy, performed in the UK NHS for serious indications including lung cancer (most common), severe traumatic injury, advanced lung infections that have destroyed lung tissue, severe tuberculosis, and rare congenital conditions. After pneumonectomy, the body undergoes a remarkable process of adaptation: the remaining lung expands to occupy more of the chest cavity, the chest and diaphragm muscles strengthen, and the circulatory system becomes more efficient at delivering oxygen.

Daily life with one lung is different but not severely limited for most people. Common adaptations include: reduced exercise capacity (you may not be able to run as far or as fast as before), shortness of breath during strenuous activities, faster fatigue, and higher risk of respiratory infections (because there is less lung tissue to reserve against infection). However, most pneumonectomy patients return to work, sports (often modified), family life and normal activities within 3-6 months of surgery. Pope Francis lived for decades with one lung after pneumonectomy as a young man, becoming one of the most public examples of normal life with single-lung capacity.

Life expectancy after pneumonectomy depends primarily on the underlying reason for lung removal. For trauma-related pneumonectomy in an otherwise healthy person, life expectancy can be near-normal. For lung cancer (the most common indication in the UK), 5-year survival depends on cancer stage at diagnosis: early-stage cancers treated by pneumonectomy can have 5-year survival rates of 40-70%, while later-stage cancers have lower rates. For severe COPD or chronic infection that required pneumonectomy, the remaining lung is also affected by the underlying disease, which affects long-term outlook. NHS lung surgeons and respiratory physicians work with patients on rehabilitation plans tailored to the specific situation.

How the body adapts after lung removal

Five main adaptations occur over weeks to months after pneumonectomy. First, compensatory lung expansion: the remaining lung gradually expands by 20-40% to occupy more of the empty chest space. This increases its surface area for gas exchange. Second, the space left by the removed lung initially fills with air, then gradually fills with fluid over weeks (this is normal and expected). Third, breathing efficiency improves: the body becomes better at extracting oxygen from each breath. Fourth, the respiratory muscles (diaphragm, intercostals) strengthen because they are working harder. Fifth, the circulatory system adapts: cardiac output adjusts and red blood cell production may increase. NHS pulmonary rehabilitation programmes accelerate these adaptations and most patients see meaningful improvement in the first 6 months post-surgery.

What activities are possible and what is limited

Most everyday activities are fully possible: walking, gentle exercise, work in non-physical jobs, family life, travel, driving. Moderate exercise is usually possible after rehabilitation: jogging, cycling, swimming, hiking on flat terrain. More challenging activities require adaptation: marathon running, high-altitude hiking, scuba diving (usually contraindicated), competitive sports requiring sustained intense effort. The key limitation is sustained high-intensity exercise where oxygen demand exceeds what one lung can supply. Many ex-pneumonectomy patients become competitive in moderate-intensity sports. Air travel is fine. Living at high altitude is generally fine although adjustment takes longer than for people with two lungs. NHS pulmonary rehabilitation teams help patients identify realistic exercise goals.

Why vapers should care about this (the wider message)

The medical possibility of living with one lung is a reassurance for patients facing pneumonectomy, but it is also a stark reminder of how much damage smoking and severe lung disease can cause. Most UK pneumonectomies are for lung cancer, the majority of which is caused by smoking. The relevance for vapers: while vape is around 95% less harmful than smoking per NHS guidance, it is not 100% safe. The risks of EVALI (mostly historical and linked to illicit THC products) and the unknown long-term effects of chronic vaping mean that maintaining healthy lungs should be a priority for everyone, especially those who switched to vape from smoking. The fact that humans can adapt to one lung does not make lung damage acceptable; it is a remarkable but limited backup, not a reason to be cavalier about respiratory health.

For UK patients facing pneumonectomy or recovering from it, the four-step framework below reflects standard NHS thoracic surgery recovery pathways.

For UK vapers concerned about long-term lung health, the appropriate context: vape is significantly less harmful than smoking and is the most effective tool for stopping smoking per multiple Cochrane reviews. However, vape is not risk-free, and maintaining healthy lungs is important. If you have respiratory symptoms (persistent cough, shortness of breath, chest pain, coughing blood) see your GP without delay; early diagnosis of lung problems dramatically improves outcomes. Our Omagh and Strabane teams can help with stepdown plans for vapers wanting to reduce or quit, including NHS Stop Smoking Service referrals.