Fire smoke can make out the outdoor training threatening to your health – exercise scientists explain how to assess the risk

As the summer radiant days many people turn to the outdoor exercises.

But in some parts of North America, pleasant weather is often consistent with the season of fires. When summer becomes more desiccated, both Frequency and intensity Fires increased, producing more smoke pollution.

Fire smoke can spread over several statesleaving people at risk of health contamination.

Exercise experts and health ask whether the benefits of outdoor exercises are negated when the sky is foggy with fire smoke.

How does air pollution cause diseases?

The components of air pollution depend on its source. For example, Air pollution related to road traffic It consists mainly of the exhaust of the vehicle, brake and tire wear, a Industrial pollution Contains significant amounts of ozone.

Fires produce huge amounts of particles floating in the air, also known as diminutive particles of solid particles. These particles have less than 2.5 micrometers – about one tenth size of pollen grain.

Particles of this size, which Air quality experts call PM2.5Lift earnest health problems because they are diminutive enough transferred to air bags in the deepest parts of the lungs. From there, they can go to the bloodstream, which leads to Zapalenie ciała – basically the reaction of the immune system struggle – which can Promote or deteriorate many chronic diseases.

Studies show that long -term exposure to fire smoke is related Lung diseasesIN heart disease AND other conditions. Because these diseases last decades, scientists believe that health problems caused by inhaling fire smoke accumulate after years of exposure.

One -time exposure to smoke can have cumulative effects

My research team and others examine how Short -term smoke exposure It can also affect long -term health results, such as heart and lung diseases.

https://www.youtube.com/watch?v=CS9O3VT7CV0

To estimate the effects of exposure to a single fire event, environmental scientists can examine various factors, such as inflammation immune markers, signs of physiological stress and heart changes, blood vessels and the nervous system. How exactly the exposure to smoke has worsened the disease It is still poorly understood, but these immediate reactions in the body may also be associated with developing chronic disease.

In a study published in June 2025, my colleagues and I examined these results in hearty participants who practiced during a fire simulation In our air inhalation laboratory. The air was filtered to contain high concentrations of PM2.5 particles produced by burning local pine – equivalent to the wind of a earnest fire.

We asked 20 generally hearty participants in the mid -1920s for exercises in a stationary cycle of about half of their maximum effort for two hours while breathing smoke. We discovered that the function of the blood and nervous system of the participants fell immediately after a smoky exercise session. These stress indicators jumped to normal within an hour of returning to the tidy air environment.

Half of our participants of the study had an increased response to physiological stress, which according to scientists may mean an increased risk chronic diseases. We chose them based on the extreme conditions test Served before the experiment: in particular their blood pressure was enriched when their hands were immersed in ice water for two minutes. Participants responding to stress experienced much stronger decreases in the function of blood vessels and the nervous system than people in a typical response group, suggesting that exercises in a very smoky climate may affect some people more than others.

Although it is impossible to predict who is the most at risk, our study emphasizes the need to thoroughly think about exposure to fire smoke.

How smoky is too smoke for outdoor exercises?

Unfortunately, precise air quality thresholds based on factors such as age and health do not exist. But some elementary guidelines and considerations can aid.

The first step is to check the air quality in which you live Airnow of the website. It uses a scale called The Air Quality Index, created by the Environmental Protection Agency in 1999 – which places air quality regionally on a scale of 0 to 500. The site can be searched according to the postal code. Reading a given region reflects the contribution of several pollution, including PM2.5 levels.

When the air quality is “good”, the decision is elementary – go out there and enjoy the outside. And there is not much debate People should generally limit their exposure to the outside When the level of air quality exceeds to the “unhealthy” threshold – or at least remember that doing it poses a health threat.

The risk and advantages of external exercises, when the air quality is “moderate” and “unhealthy for sensitive”, is less clear, especially for people who do not have chronic health conditions.

Risk assessment

One of the main factors to decide when and whether to exercise outside is your health. Airnow recommends That people with chronic conditions commit caution and remain indoor when smoke levels cause that air quality assessment is approaching the “unhealthy for sensitive” category.

This advice can be obvious to people with Diagnosed lung conditions Such as asthma or chronic obstructive lung disease, taking into account that fire smoke particles deteriorate the lungs. But research suggests that this also applies to milder disease states. For example, a enormous study of people with increased, but not clinically high blood pressure showed that people who lived in the wind from air pollution Develop high blood pressure And ultimately heart disease.

Another issue is time of day. As the afternoon heated the air column, which we breathe, expands, diluting the number of particles. And the afternoon winds often blow out stagnous air from the valleys and areas of downtown, in which particles can focus in cooler parts of the day. This means that evening trainings can be safer than early morning, although the key confirmation with air quality readings is crucial.

The intensity in which you practice is also significant. Exercise with a higher intensity means deeper, more repeated breathing, which probably increases your exhibition to harmful air. So you can choose shorter jogging in a longer gear When the air quality is moderate or penniless.

My laboratory is currently working on quantitatively how much pollution a person breathes During exercises in smoky conditionsBased on the intensity of efforts, exercise time and the number of local solid particles. This research line is still in its infancy, but our early findings and other published studies suggest that when fire smoke puts air quality in the field of “moderate” and “unhealthy for sensitive”, people can reduce the effects of smoke exposure, reducing the intensity of exercises or time spending outside.