It is possible to live with only one lung, usually following the surgical removal of one (a pneumonectomy). The remaining lung must take over the entire function of oxygenating the blood and removing carbon dioxide, permanently altering respiratory function. Despite this significant physiological adjustment, most people who undergo this procedure can return to a relatively normal life, though usually with some limitations on physical exertion.
Reasons for Having Only One Lung
The primary reason an individual lives with a single lung is the surgical necessity to remove one due to severe, localized disease or trauma. Lung cancer is the most common condition requiring a full pneumonectomy, especially when the tumor is large or located centrally. Other acquired conditions necessitating removal include severe infectious diseases (like extensive tuberculosis or fungal infections) and chronic inflammatory conditions (like advanced bronchiectasis).
Irreparable traumatic injury to the chest can also force removal. In rare cases, a person may be born with only one lung, a congenital condition called pulmonary agenesis. Whether the loss is acquired or congenital, the remaining lung must be healthy and fully functional for long-term survival.
The Body’s Physiological Adjustment
The remaining lung undertakes a remarkable biological compensation to manage the body’s entire gas exchange demand. This process involves a physical expansion known as compensatory hyperinflation, where the lung grows to occupy the vacated chest cavity space. This expansion increases the total volume and surface area available for gas exchange within the remaining lung tissue.
The mediastinum, the central compartment of the chest containing the heart and major blood vessels, also shifts toward the empty side to stabilize the chest cavity. This shift, combined with the diaphragm rising on the operative side, reduces the overall empty space, allowing the remaining lung to work more efficiently. The body also recruits previously unused alveolar units within the remaining lung, effectively increasing the number of sites where oxygen can enter the bloodstream.
A significant cardiovascular adjustment involves rerouting the entire cardiac output from the right side of the heart into the single pulmonary artery. The remaining lung’s vascular network must handle 100% of the blood flow previously split between two lungs. While the vascular bed can dilate to accommodate this increased flow at rest, this sustained pressure increase poses a long-term risk of pulmonary hypertension.
Managing Life with Reduced Lung Capacity
Living with one lung means accepting a permanent reduction in the capacity for strenuous physical activity. While normal daily tasks are generally manageable, high-intensity or vigorous exercise often leads to shortness of breath due to the reduced gas exchange surface area. Exercise tolerance is typically diminished, and individuals must learn to manage their pace and adapt their activities.
Environmental factors require careful consideration, particularly exposure to airborne pollutants, smoke, or respiratory irritants that could damage the single functioning lung. Altitude sensitivity is also a concern, as the lower oxygen concentration in the air at high elevations can quickly overwhelm the reduced respiratory reserve. Individuals also face an increased vulnerability to respiratory infections, such as the flu or pneumonia, which can rapidly compromise the entire respiratory system.
Long-term care centers on preventative measures and consistent monitoring to protect the remaining lung. Regular check-ups are important for managing potential long-term complications, such as the risk of developing pulmonary hypertension. Pulmonary rehabilitation programs provide techniques and exercises to maximize the efficiency of the single lung, helping individuals maintain the best possible quality of life.