“Frozen lung” can refer to two distinct concepts: the physiological impact of extremely cold environmental air on the respiratory system, and the scientific process of preserving lungs at very low temperatures for medical purposes. While inhaling cold air can significantly affect the lungs, the term “frozen lung” in this context typically describes the adverse reactions of the airways rather than actual tissue freezing within the body. Conversely, the medical use of “frozen lungs” involves advanced techniques to store organs for future use.
How Extreme Cold Affects Lungs
Inhaling very cold air triggers several physiological responses. The cold, dry air irritates the sensitive lining of the airways, prompting a reflexive narrowing of the bronchial tubes, bronchoconstriction. This limits cold air reaching lung tissue, but makes breathing difficult. The body also increases mucus production to humidify the incoming air and trap irritants, leading to coughing.
Individuals with pre-existing respiratory conditions, such as asthma or chronic obstructive pulmonary disease (COPD), are particularly susceptible to these effects. For these individuals, cold air can trigger exacerbated symptoms, including wheezing, shortness of breath, and severe coughing spells. While the deep lung tissue does not typically freeze from breathing cold air, prolonged exposure to extremely frigid temperatures can, in rare cases, lead to frostbite in the upper respiratory tract. This is distinct from the primary lung tissue.
Protecting Lungs in Cold Weather
Several strategies can help mitigate the adverse effects of cold air. Breathing primarily through the nose is beneficial because the nasal passages warm and humidify the air before it reaches the lower airways. Covering the mouth and nose with a scarf or balaclava provides warmth and moisture to inhaled air. This barrier reduces the impact of frigid, dry air.
Maintaining adequate hydration is also important, as it keeps mucous membranes moist and supports natural humidification. Individuals should avoid strenuous physical activity in extremely cold conditions, especially those with pre-existing respiratory issues, as increased breathing rates amplify the exposure to cold air. Paying attention to personal limits and retreating indoors when discomfort arises can prevent more severe respiratory reactions.
Freezing Lungs for Medical Purposes
The medical application of “frozen lungs” centers on cryopreservation, a technique used to preserve biological materials at ultra-low temperatures. This process aims to halt all biological activity, allowing for long-term storage of organs like lungs for research or potential transplantation. The main challenge in lung cryopreservation is preventing the formation of damaging ice crystals within cells and tissues, which can rupture cell membranes and render the organ non-viable. Scientists use cryoprotective agents (CPAs), solutions that penetrate cells to lower their freezing point, to minimize ice formation.
Current clinical lung transplantation primarily relies on static cold storage, where organs are flushed with a preservation solution and kept on ice at 0-4°C. This method slows down metabolic processes but does not stop them entirely, restricting the viable storage window. Emerging cryopreservation methods, such as vitrification, aim to solidify the organ without ice crystal formation using higher CPA concentrations and rapid cooling. While full organ cryopreservation for routine transplantation remains a scientific hurdle due to CPA toxicity and challenges in uniform cooling and rewarming, ongoing research is exploring these advanced techniques to extend preservation time and increase viable donor lung availability.