Smoke exposure and irregular heartbeat in firefighters

By Jessica Muñoz | October 2025

Firefighters who battle more blazes each year face a higher risk of developing an irregular heartbeat known as atrial fibrillation (AFib), according to new research published in the Journal of the American Heart Association (2022).

The nationwide study surveyed more than 10,000 active U.S. firefighters and found a clear link between the number of fires fought and the likelihood of being diagnosed with AFib (Vanchier, et all, 2022). AFib is an irregular and often very rapid heart rhythm. During AFib the atria beat chaotically and irregularly and out of sync with the ventricles. People with AFib will report a fast, pounding heartbeat, shortness of breath or light-headedness (Mayo, 2025).

Risk rises with every fire

Researchers discovered that firefighters who responded to more than 30 fires a year had an AFib rate of 4.5%, compared with just 2% among those who fought five or fewer fires annually. Even after accounting for age, blood pressure, and other health risks, every additional five fires per year increased AFib odds by about 14% (Vounchier, et al, 2022).

Stress, heat, and smoke exposure likely factors

The study suggests that repeated exposure to smoke, heat, dehydration, and intense physical and emotional stress may strain the heart and disrupt normal rhythms. Firefighters also face long shifts and irregular sleep patterns, all of which can contribute to cardiovascular problems.

“Firefighting is an incredibly demanding profession,” researchers noted. “These results show that heart health monitoring is just as important as injury prevention on the job (Vounchier, et al, 2022).

Protecting those who protect others

While the study does not prove that fire exposure directly causes AFib, experts say the evidence points to a need for greater awareness and prevention.

There are ways to assess for AFib. The first is with simple methods such as taking a pulse check to identify irregular rhythms. An ECG would need to be obtained for diagnostic testing by a health care provider. With advanced technology there is also remote patient monitoring as an option for early detection (Detect Afib, 2024).

Case study

Patient: 38-year-old male firefighter

Medical history: Healthy, non-smoker, no prior cardiovascular disease, regular exercise

Occupational exposure: Responded to a large warehouse fire lasting 4 hours. During firefighting, he was exposed to heavy smoke, including carbon monoxide and particulate matter, despite wearing protective gear intermittently.

Presenting symptoms: The following morning, he experienced palpitations, mild shortness of breath, dizziness, and fatigue. He denied chest pain or syncope.

Examination

• Vital signs: BP 138/84 mmHg, HR 128 bpm (irregular), RR 20/min, O2 sat 95% on room air
• Cardiovascular: Irregularly irregular rhythm, no murmurs
• Lungs: Mild wheezing, otherwise clear
• Neurological: Alert, oriented, no focal deficits

Investigations

• ECG: Revealed atrial fibrillation with rapid ventricular response (RVR)
• Blood tests: Elevated carboxyhemoglobin level at 8%, troponin normal, electrolytes within normal limits
• Echocardiogram: Structurally normal heart, normal ejection fraction

Management

• Administered supplemental oxygen for CO clearance
• Rate control with oral beta-blocker (metoprolol)
• Monitored for hemodynamic stability; anticoagulation considered
• Advised avoidance of further smoke exposure until cleared

Outcome

• Heart rhythm spontaneously reverted to sinus rhythm after 24 hours of monitoring and oxygen therapy
• Patient educated on early recognition of arrhythmia symptoms and proper use of protective equipment
• Follow-up with cardiology and occupational medicine arranged; continued normal sinus rhythm at 1-month follow-up

Atrial fibrillation with rapid ventricular response

Courtesy: Jessica Muñoz

Conclusion

Firefighters face occupational hazards that extend beyond burns and physical injuries, including an increased risk of developing atrial fibrillation due to repeated exposure to smoke, heat, stress, and irregular work patterns. The case study of a 38-year-old firefighter illustrates how acute smoke exposure can trigger new-onset AFib, even in healthy individuals. Regular cardiovascular monitoring, pulse checks, ECGs, and emerging remote monitoring technologies are critical tools for protecting heart health in this high-risk population. Preventive measures, proper use of protective equipment, and awareness of early symptoms can help ensure that those who protect the public are also protecting their cardiovascular well-being.

Works cited

1. Detect Afib. (2024). Assessing for AFib in at-risk patients. Bristol Myers Squibb / Pfizer. Retrieved October 6, 2025, from https://www.detect-afib.com/assessing-afib?cid=sem_1743552&gclid=b14719e68c3b128e347f710575056d92&gclsrc=3p.ds
2. Vanchiere, C. M., Smith, D. L., Kales, S. N., Soteriades, E. S., Tsismenakis, A. J., Kim, J. H., & Patterson, P. D. (2022). Association between atrial fibrillation and occupational exposure in firefighters. Journal of the American Heart Association, 11(6), e022543. https://doi.org/10.1161/JAHA.121.022543
3. Mayo Clinic Staff. (2025, October 3). Atrial fibrillation: Symptoms and causes. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/atrial-fibrillation/symptoms-causes/syc-20350624