A recent study from Japan suggests that wearing face masks, widely adopted during the Covid-19 pandemic, may offer protection against certain types of heart attacks triggered by air pollution. Researchers from Kumamoto University analyzed data from over a quarter of a million heart attack patients in Japan between 2012 and 2022, focusing on the link between short-term exposure to PM2.5 particles and heart attack risk.

PM2.5, tiny airborne particles originating from vehicles, industry, and household heating, can penetrate deep into the lungs and significantly elevate the risk of all types of heart attacks. The study revealed a particularly strong association between PM2.5 exposure and a specific subtype known as Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA).

Professor Chris Gale, a consultant cardiologist at Leeds Teaching Hospitals NHS Trust, explains that MINOCA accounts for 5-10% of all heart attacks, affecting approximately 10,000 people annually in the UK, and is more prevalent among women and younger individuals. This condition occurs without major blockages in the heart's arteries and can be triggered by factors like artery spasm, issues with the heart's small blood vessels, or inflammation, all of which air pollution can exacerbate. Polluted air contributes to oxidative stress, reduces nitric oxide (vital for blood vessel relaxation), and increases the arteries' susceptibility to tightening.

The Japanese study, published in the European Heart Journal, observed a decline in the PM2.5-related risk of MINOCA after the pandemic's onset. The researchers concluded that this reduction was likely due to the rapid adoption and consistent practice of mask-wearing in Japan, rather than strict lockdowns, as the country did not impose them extensively. This provides compelling evidence that simple protective measures, such as mask-wearing, can mitigate cardiovascular risks linked to environmental exposures.

Further research supports the broader benefits of face coverings beyond preventing virus spread. Professor Jonathan Grigg, a professor of paediatric respiratory and environmental medicine at Queen Mary University of London, highlighted his own study, which found that wearing an FFP2 mask halved the amount of inhaled particles entering the bloodstream when volunteers were exposed to traffic pollution. He suggests that vulnerable individuals, such as those recovering from a heart attack, could benefit from FFP2 masks in highly polluted areas like busy roads.

Professor Zongbo Shi from the University of Birmingham concurs with the findings, noting that both short-term and long-term PM2.5 exposure increases the risk of numerous health conditions, including heart attacks. He recommends wearing face masks in polluted environments, such as alongside busy roads or on older lines of the London Underground, known for high dust levels, particularly the Northern Line which had the highest dust levels in a 2024 report.

While mask-wearing offers a short-term protective measure, improving air quality remains a critical long-term priority for reducing heart risks. Professor Gale emphasizes a holistic approach to reducing heart attack risk, including a heart-healthy lifestyle: quitting smoking, adopting a balanced, lower-salt diet (like the Mediterranean diet), maintaining a healthy weight, and engaging in at least 150 minutes of moderate exercise weekly. Professor Shi adds that awareness should extend beyond vehicle pollution to other sources like wood burners, which are major contributors to outdoor and, if improperly managed, indoor air pollution. Reducing wood burning, especially of wet wood or with restricted airflow, could yield significant health benefits for residents.