Microplastic fears have dominated social media, news, and public conversations in recent years, and concerns about their impact on human health continue to grow. For runners, avoiding plastic is nearly impossible. Used in water bottles, energy gel packaging, shoes, apparel, and more. But how do microplastics actually affect us? And are we at higher risk for exposure to them? We spoke to experts about the science behind the presence of plastics in running shoes and their potential health effects.
The dangers of microplastics
Microplastics pose risks to both human health and the environment. Sharon Dodd A family physician in Richmond, B.C., and an active member of the British Columbia regional committee of the Canadian Association of Environmental Physicians, cautions caution.
“This is a two-pronged problem: plastic and chemicals added to that plastic,” Dodd said. canadian running. “Per- and polyfluoroalkyl substances (PFAS), also known as permanent chemicals, can leach from plastics and are present in nearly every organ.”
Although research on the health effects of microplastics is still evolving, Dodd said there is growing evidence that exposure to both microplastics and PFAS is associated with a variety of health concerns.
“These chemicals and plastics often find their way into the brain,” Dodd says. “Researchers found that levels were much higher in people who died from Alzheimer’s disease than in people who didn’t. This is just one concern. Alzheimer’s disease is also associated with cardiovascular problems and many reproductive disorders.”
microplastic. Photo: Lukasz Kobus/Wikicommons
How exposed are runners?
Microplastics are present almost everywhere, including in the air we breathe. Indoor environments typically contain higher concentrations than outdoors due to the continuous shedding of fibers from furniture, carpets, and synthetic fabrics. However, there is one piece of reassuring news.
“Our skin has so many layers of cells that larger sized microplastic particles cannot penetrate,” Dodd says. “The big danger for our clothes is that when we wash them, when we drain them, that water is filled with microplastics from synthetic clothing, which tends to leak into natural water sources.”

Environmental impacts also affect human health. Microplastics are increasingly being detected in soil, seafood, and agricultural products, and ingestion is one of the main routes of exposure.
Runners need to stay hydrated during training and often use reusable plastic bottles or hydration bags to do so, but these can also increase the risk of exposure to microplastics.
“When it comes to hard plastic water bottles and pouches that store water, everything is going to leach to some degree,” Dodd said. “The presence of chemicals increases, especially if these bottles are stored in a warm environment.”
How about gel! ?
Energy gels are one of the most consumed products by runners, and almost all of them are packaged in flexible plastic. If swallowing microplastics is the main route of exposure, are we flooding our bodies with microplastics?
conor wilsonThe owner and sustainability consultant of Canadian nutrition and gel brand Olway Performance says gel packaging is much more complex than it appears.
“The outer film is typically a layer of polypropylene or polyester and primarily handles printing and stiffness,” Wilson says. “The intermediate film is a barrier, usually a metalized polyester or fine aluminum layer, which blocks out light, oxygen, and moisture to extend shelf life. The inner film is polyethylene and is a food-safe layer that touches the product and heat-seals the package.”

This multilayer structure helps preserve the product, but it also relies on plastics that are commonly associated with microplastic pollution.
“Polyethylene definitely breaks down and releases microplastics, especially when heated,” Dodd says. “Additional chemicals such as PFAS, which remain in the human body permanently, can also leach.”
reduce exposure
While research continues into the health effects of microplastics, there are practical ways runners can reduce their exposure.
Dodd recommends using metal water bottles if possible. While the use of plastic flasks and hydration packs may be unavoidable during long runs or races, switching to metal bottles before and after training can reduce unnecessary exposure. They also recommend keeping water bottles away from heat and cleaning them regularly. Water left in plastic bottles can contain high levels of chemicals and microplastics, so be sure to refill the bottle with fresh water before each run and wash it between uses.
The same principle of exposure to heat applies to gels. This is because holding the gel close to your body can warm up the packaging and increase the presence of chemicals. You may be able to minimize your exposure to microplastics by storing your gel in a cool place or refrigerating it before your run. Making your own gel and storing it in a non-plastic container before running can reduce chemical intake compared to gels stored in plastic packaging.

