Hot Tub Lung: Causes, Symptoms, and Prevention Tips (2026)

Hot Tub Lung is a rare but serious respiratory condition caused by inhaling aerosolized bacteria, most commonly Mycobacterium avium complex (MAC), that thrive in warm, moist environments like hot tubs, indoor pools, and humidifiers.

Despite its name, this illness isn’t caused by the water itself but rather by tiny airborne droplets containing bacteria that can trigger an immune response in the lungs. People affected often experience symptoms similar to pneumonia or hypersensitivity pneumonitis, including cough, shortness of breath, fatigue, and fever.

Understanding how Hot Tub Lung develops, who’s at risk, and how it can be prevented is essential for protecting your respiratory health, especially if you frequently use hot tubs or similar environments.

What Is Hot Tub Lung?

Hot Tub Lung is a lung condition linked to inhaling certain bacteria found in hot tubs, spas, and similar environments. The illness can affect anyone, though it is more common in some groups and develops due to distinct biological mechanisms.

Definition and Overview

Hot Tub Lung is a type of hypersensitivity pneumonitis caused by inhaling aerosolized bacteria, mainly Mycobacterium avium complex (MAC). This condition is not an infection but rather an immune response to breathing in contaminated water vapor or steam.

People with Hot Tub Lung may experience symptoms such as cough, shortness of breath, fever, and fatigue. The signs can resemble other respiratory illnesses, which often makes diagnosis challenging.

Doctors diagnose Hot Tub Lung based on a combination of patient history, symptoms, chest imaging, and laboratory findings. Prompt medical attention is important, as untreated cases can lead to chronic lung issues or lasting scarring.

Causes and Risk Factors

The primary cause is exposure to hot tubs, spas, or pools contaminated with nontuberculous mycobacteria, particularly MAC. These bacteria are resistant to standard levels of chlorine and thrive in warm, moist environments.

Risk increases with frequent or prolonged use of poorly maintained hot tubs. People with weakened immune systems, chronic lung diseases, or a history of allergies may be more susceptible.

Using high-pressure jets or keeping spa covers on while using hot tubs can contribute to higher concentrations of bacteria-laden mist. Proper ventilation and regular maintenance lower, but do not eliminate, the risk of developing Hot Tub Lung.

How Hot Tub Lung Develops

The condition develops when a person repeatedly inhales small particles of water containing Mycobacterium bacteria. The body’s immune system reacts to the bacteria present in the droplets, causing inflammation of the lung tissue.

This immune response leads to symptoms typical of hypersensitivity pneumonitis: coughing, breathing problems, and sometimes fever. The reaction can be acute after heavy exposure or chronic with repeated lower-level exposures over time.

If exposure continues without treatment or removal from the source, lung inflammation can progress and cause permanent damage. Stopping exposure and seeking medical care are key steps in preventing serious complications.

Symptoms of Hot Tub Lung

Hot Tub Lung primarily affects the respiratory system, often leading to persistent breathing problems. Symptoms can resemble other lung conditions but have features that help distinguish this illness.

Common Respiratory Symptoms

People with Hot Tub Lung often report a chronic, dry cough that does not resolve with typical cold remedies. Shortness of breath is frequent, especially during physical activity or even minor exertion. Some individuals also note chest tightness or mild pain.

Other possible symptoms include fatigue, low-grade fever, and mild weight loss. Night sweats may occur in some cases, although they are less common. Many people notice their breathing problems worsen within hours to days after exposure to hot tubs or similar environments.

Symptoms usually appear gradually rather than suddenly. Not everyone experiences all symptoms, but a persistent cough and progressive shortness of breath are the most consistent findings. In rare cases, mild wheezing or crackles might be heard when a healthcare provider listens to the chest.

Long-Term Health Effects

If Hot Tub Lung is not identified and exposure continues, symptoms can last for months or even years. In some patients, repeated or prolonged inflammation can lead to scarring (fibrosis) of lung tissue, which may cause permanent breathing limitations.

Most people recover fully if they avoid further exposure and receive appropriate treatment. However, a minority may continue to experience symptoms like fatigue or shortness of breath. Children, older adults, and people with weakened immune systems are more likely to experience long-term issues.

For those with underlying lung diseases, recovery can be slower. Rarely, Hot Tub Lung can increase sensitivity to other respiratory irritants. Prompt recognition and intervention help prevent these long-term effects, emphasizing the importance of early diagnosis.

Differences from Other Pulmonary Diseases

Hot Tub Lung shares many symptoms with asthma, pneumonia, and hypersensitivity pneumonitis. However, it is caused specifically by inhalation of aerosolized nontuberculous mycobacteria from hot tubs, therapy pools, or similar environments.

Unlike typical pneumonia, Hot Tub Lung rarely presents with high fever, chest pain, or significant sputum production. It does not respond to usual antibiotics used for bacterial pneumonia. Asthma medications may offer only temporary relief.

Health care providers look for a history of hot tub or spa use, along with symptoms, to distinguish this condition from others. Laboratory tests can confirm the presence of nontuberculous mycobacteria in respiratory samples, which helps solidify the diagnosis. Imaging tests often reveal patchy areas in the lungs, which do not look the same as classic bacterial or viral infections.

Diagnosing Hot Tub Lung

The diagnosis of hot tub lung relies on a combination of clinical features, exposure history, imaging studies, and laboratory results. Each step addresses a specific aspect of the process to ensure accurate detection and differentiation from other respiratory illnesses.

Medical History and Physical Examination

A careful medical history is crucial. Patients often report spending extended time in hot tubs, spas, or indoor pools. Common symptoms include persistent cough, shortness of breath, and sometimes fever.

During the physical examination, doctors listen for abnormal lung sounds, such as crackles. Vital signs may reveal mild hypoxemia, especially during exertion. Asking about timing and frequency of water exposure helps identify possible sources of infection.

Other risk factors, like past lung problems or compromised immunity, may also be relevant. Physicians must distinguish hot tub lung from similar illnesses, such as hypersensitivity pneumonitis or pneumonia.

Imaging and Laboratory Tests

Chest imaging typically shows patterns consistent with hypersensitivity pneumonitis. High-resolution CT (HRCT) scans often reveal areas of ground-glass opacities and small nodular densities.

Chest X-rays may show diffuse infiltrates, but these findings are not unique to hot tub lung. Pulmonary function tests can demonstrate a restrictive pattern and reduced diffusing capacity.

Bloodwork may show increased white blood cells or mild inflammation. Bronchoalveolar lavage may be used to collect lung samples, which can then be tested for signs of infection and specific immune responses.

Identifying nontuberculous mycobacteria

Confirmation depends on identifying nontuberculous mycobacteria (NTM), most often Mycobacterium avium complex, in respiratory samples or from water sources. Sputum cultures are obtained to detect the presence of NTM.

Special staining and cultures are needed because NTMs do not show up on routine bacterial cultures. Polymerase chain reaction (PCR) techniques may also help in detecting the genetic material of NTM.

Supporting diagnosis, NTM is often detected in both patient sputum and water from the suspected hot tub. The presence of the organism in both environments is a strong indicator of hot tub lung.

Treatment and Management Options

Managing hot tub lung requires timely diagnosis, an appropriate care plan, and adjustments to daily life. Treatment focuses on symptom control, removing the cause, and close medical follow-up for long-term lung health.

Medications and Therapies

Most cases of hot tub lung respond to environmental changes, but medications may still be necessary. Corticosteroids are often prescribed to reduce lung inflammation. They may be given orally or, in severe cases, intravenously. The dose and duration depend on individual response and symptom severity.

Some patients benefit from supplemental oxygen if their blood oxygen is low. In rare cases where symptoms persist, immunosuppressive therapies might be considered. Antibiotics are not typically used since the condition is caused by immune response to bacteria, not an active infection.

Lung function should be monitored throughout therapy. Adverse effects from steroids—such as blood sugar changes or risk of infection—should be checked during treatment.

Lifestyle Adjustments

Avoiding exposure to hot tubs, indoor pools, and spas is the most critical adjustment. Any water-related activity using poorly maintained or heavily chlorinated water can trigger symptoms. Patients are advised to thoroughly clean or avoid personal hot tubs and similar environments.

Improvement in home ventilation and using high-efficiency particulate air (HEPA) filters can reduce exposure to airborne irritants. Those with underlying lung conditions may need extra precautions to limit contact with potential waterborne pathogens.

Adopting healthy habits, including quitting smoking and regular exercise as tolerated, can also help support lung recovery. Open communication with healthcare providers about lifestyle changes is important for preventing recurrence.

Monitoring Recovery and Prognosis

Regular follow-up visits are essential to track recovery. Pulmonary function tests, chest x-rays, or CT scans may be used to assess progress. Patients should watch for return of symptoms like cough, shortness of breath, or fatigue.

Recovery time varies but most cases improve within weeks to months after avoiding further exposure. Some individuals may need long-term follow-up if lung function remains impaired.

Relapses are possible if exposure is not fully eliminated. Early intervention and ongoing medical assessment can help reduce the risk of complications and support optimal lung health.

Prevention and Hot Tub Safety

Consistent care and precise hygiene are key to minimizing the risk of Hot Tub Lung. Proper hot tub maintenance and practical steps can dramatically reduce harmful microbe growth.

Hot Tub Maintenance Practices

Routine hot tub maintenance is essential for safety. Water should be tested for sanitizer levels—like chlorine or bromine—before each use. pH levels should be kept between 7.2 and 7.8, as improper balance can decrease sanitizer effectiveness. Filters should be cleaned or replaced as recommended by the manufacturer, usually every 2–4 weeks.

Hot tubs must be drained and scrubbed every 3–4 months to prevent biofilm buildup, which supports bacterial growth. Covered tubs accumulate less debris, but covers must also be cleaned frequently to avoid mold. Bathers should shower before use to limit organic contaminants that feed bacteria.

Reducing Exposure to Mycobacteria

Mycobacteria thrive in warm, moist environments like hot tubs. Maintaining sanitizer levels at or above recommended concentrations is crucial, as these bacteria are resistant to low chlorine levels. Always avoid using a hot tub when the water is cloudy, or if a strong musty odor is present, as these may indicate contamination.

Proper ventilation in indoor areas is important, since inhalation is the primary route of exposure. People with weakened immune systems, lung problems, or chronic illnesses should avoid public or poorly maintained hot tubs. Regular reminders and visible maintenance logs can help ensure everyone using the hot tub follows safe practices.

Risk Groups and Vulnerable Populations

Hot Tub Lung does not affect everyone equally. Certain groups face a higher risk of developing symptoms and complications due to their health status or age.

Individuals with Pre-existing Lung Disease

People with chronic lung diseases—such as asthma, chronic obstructive pulmonary disease (COPD), or cystic fibrosis—are especially susceptible to Hot Tub Lung. Mycobacterium avium complex can worsen underlying respiratory issues, leading to more severe symptoms like chronic cough, shortness of breath, and fatigue.

Those who use inhaled corticosteroids or other immune-suppressing medications face increased danger, as their ability to fight off infection is reduced. In this group, exposure to aerosolized water from contaminated hot tubs may cause flare-ups that are harder to control and recover from.

Symptoms in these individuals can linger even after the source of exposure is removed. Long-term or repeated exposure may result in decreased lung function.

Children and Older Adults

Children are at risk because their immune systems are not fully developed, making them less able to clear bacteria from their lungs after exposure. Even brief contact with contaminated hot tubs can lead to symptoms such as coughing, wheezing, and fever.

Older adults often have weaker immune defenses, especially if they have other chronic conditions. As a result, they may develop more intense symptoms and be slower to recover from lung inflammation caused by Mycobacterium avium complex.

Both children and older adults may require more intervention, such as extended medication or hospital care, compared to healthy adults. Prompt recognition and avoidance of exposure are important for these age groups.

FAQs About Hot Tub Lung

Can Hot Tubs Cause Lung Problems?

Yes, hot tubs can cause lung problems, especially when not properly cleaned and maintained. Inhaling aerosolized water droplets containing bacteria such as Mycobacterium avium complex (MAC) can lead to a condition called Hot Tub Lung.

This can trigger inflammation in the lungs and cause symptoms similar to pneumonia or hypersensitivity pneumonitis. Ensuring proper sanitation and ventilation can significantly reduce the risk of lung-related complications from hot tub use.

Can You Get an Upper Respiratory Infection from a Hot Tub?

Yes, it’s possible to develop an upper respiratory infection from a hot tub if it’s contaminated with bacteria or mold. The warm, humid environment can foster microbial growth, which may be inhaled through steam or water droplets.

Infections can result in coughing, sore throat, congestion, or more serious conditions like Hot Tub Lung. Proper maintenance, regular cleaning, and ensuring chemical balance in the water are key to preventing these types of infections.

How Do You Get Hot Tub Lung?

Hot Tub Lung is caused by inhaling aerosolized bacteria—most commonly Mycobacterium avium complex (MAC)—found in warm, moist environments like hot tubs. These bacteria become airborne through steam or bubbling water and, when inhaled, can trigger an immune response in the lungs.

The condition is not an infection in the traditional sense, but rather a hypersensitivity reaction. Poorly maintained or frequently used hot tubs are more likely to harbor the bacteria that cause this condition.

How Common Is Hot Tub Lung?

Hot Tub Lung is relatively rare, but it can occur in individuals who frequently use hot tubs, especially those with poor maintenance or inadequate ventilation. While not considered a widespread health concern, cases are often underreported or misdiagnosed as pneumonia or asthma.

People with weakened immune systems or pre-existing respiratory issues may be at greater risk. Awareness of proper hot tub hygiene can help prevent the condition from developing in the first place.

What Are the Symptoms of Hot Tub Lung?

Symptoms of Hot Tub Lung often resemble those of pneumonia or chronic respiratory conditions. Common signs include persistent cough, shortness of breath, fatigue, low-grade fever, and chest tightness. Some people may also experience weight loss or night sweats.

These symptoms typically develop gradually and worsen with continued exposure to contaminated hot tub environments. If symptoms persist after hot tub use, medical evaluation and imaging (like a chest X-ray or CT scan) are often necessary.

Does Hot Tub Lung Go Away on Its Own?

Hot Tub Lung may improve on its own if exposure to the contaminated source is stopped, but medical intervention is often necessary. In some cases, corticosteroids or other anti-inflammatory medications are prescribed to reduce lung inflammation. Severe or prolonged cases may require more intensive treatment.

Note: It’s important to consult a healthcare provider for diagnosis and guidance, as untreated cases can lead to chronic respiratory problems or long-term lung damage.

Why Do I Feel Short of Breath in a Hot Tub?

Feeling short of breath in a hot tub can result from several factors, including high humidity, warm temperatures, or inhalation of chemicals or bacteria in the steam. For individuals with asthma or other lung conditions, these environments can trigger airway irritation or inflammation.

In some cases, it could be an early sign of Hot Tub Lung or another respiratory reaction. If you consistently experience breathing issues in a hot tub, it’s important to seek medical advice.

Can Too Much Chlorine in a Hot Tub Hurt Your Lungs?

Yes, excessive chlorine levels in a hot tub can irritate the respiratory tract. Inhaling chlorinated steam can cause coughing, throat irritation, and even exacerbate asthma or other lung conditions. Chronic exposure may damage lung tissues or contribute to respiratory sensitivity.

Properly balancing chlorine levels is essential—not only to kill bacteria but also to prevent chemical-related breathing problems. Using a well-ventilated hot tub and checking chemical levels regularly helps reduce this risk.

What Does Hot Tub Lung Feel Like?

Hot Tub Lung can feel like a lingering respiratory illness. People often report a persistent dry cough, shortness of breath, fatigue, low-grade fever, and chest discomfort. It may feel like you’re coming down with pneumonia or bronchitis that doesn’t go away.

Symptoms often worsen after hot tub use and improve when exposure stops. Because it mimics other respiratory illnesses, medical evaluation is essential for accurate diagnosis and proper treatment.

How to Prevent Hot Tub Lung?

To prevent Hot Tub Lung, maintain your hot tub properly with regular cleaning, disinfecting, and water testing. Make sure chlorine or bromine levels are balanced and that the tub is adequately ventilated. Limit time in steamy or bubbling hot tubs, especially if you have respiratory issues.

Note: Avoid using hot tubs with visible mold, cloudy water, or strong chemical smells. Routine maintenance and avoiding prolonged exposure to mist or steam significantly lower your risk.

Is Hot Tub Lung Dangerous?

Hot Tub Lung can be dangerous if left untreated. While not typically life-threatening, it can lead to chronic lung inflammation, scarring, and long-term breathing difficulties. The condition can mimic more serious illnesses like tuberculosis or pulmonary fibrosis.

With proper diagnosis and management, including avoiding further exposure and possibly using medications, most people recover. However, prompt medical attention is essential to prevent complications and ensure full recovery.

How Long Does It Take for Hot Tub Lung to Go Away?

The duration of recovery from Hot Tub Lung varies. Symptoms may begin to improve within days to weeks after avoiding the source of exposure, especially with medical treatment such as corticosteroids.

Full recovery can take several weeks to a few months, depending on the severity of the inflammation and how early the condition was diagnosed. Continued exposure can delay healing or lead to chronic lung issues, so prompt intervention is crucial.

Final Thoughts

Although Hot Tub Lung is uncommon, it serves as a reminder that even relaxing environments can pose hidden health risks. By maintaining proper hygiene in hot tubs, regularly disinfecting equipment, and ensuring adequate ventilation, you can reduce your exposure to potentially harmful bacteria.

If you develop unexplained respiratory symptoms after using a hot tub or indoor water source, seeking prompt medical attention is crucial for early diagnosis and treatment. With awareness and preventive steps, Hot Tub Lung is both manageable and largely avoidable.