Article: What Wearing Synthetic Fabrics Every Day Does to Your Body
What Wearing Synthetic Fabrics Every Day Does to Your Body
It's not just the gym session. It's the hours before and after it too.
The earlier posts in this journal focused on what happens during exercise in synthetic activewear: elevated sweat production, higher skin temperature, increased blood flow, sustained friction against synthetic fabric.
That's the acute exposure window. It's also not the only one.
Most people who train five days a week are also wearing synthetic fabrics outside of training. Polyester shirts. Nylon shorts. Spandex-blend underwear. Synthetic socks. The gym session is the highest-intensity contact window. But it's surrounded by hours of lower-intensity contact that add up in their own right.
The Cumulative Daily Picture
Activewear has moved beyond the gym:
Athleisure has normalised wearing synthetic performance fabrics as everyday clothing. Leggings, sports bras, and moisture-wicking shirts are worn for the school run, the commute, and casual use as frequently as for actual training. What was a one-hour daily exposure window has extended into an all-day one for many people.
Skin is your largest organ:
The average adult has roughly 2 square metres of skin, and it's in contact with clothing for most of the day. Research into dermal absorption of chemicals from clothing has historically lagged behind research into ingestion and inhalation, because skin was assumed to be an effective barrier. The University of Birmingham 2024 study, detailed in Post 18, was the first experimental evidence that this assumption needs updating for synthetic fabrics under sweat conditions.¹
The washing machine releases what the body doesn't absorb:
Every wash cycle releases microplastic fibres from synthetic clothing into wastewater. Synthetic garments release between 640,000 and 1,500,000 microplastic fibres per wash cycle.⁵ Those fibres enter water systems, accumulate in the food chain, and eventually cycle back through the body via food and water. The garment sheds in two directions simultaneously: toward the skin during wear, and into the environment during washing.
The Exposure Inventory
A serious gym-goer wearing synthetic activewear for training, plus synthetic casual clothing for daily wear, and washing both regularly accumulates a significant daily synthetic fabric exposure profile. Broken into its components:
Dermal exposure during training (high-sweat, high-absorption conditions), dermal exposure during casual wear (lower intensity, longer duration), inhalation of shed fibres during wear and in the laundry environment, and environmental reingestion through food and water contaminated by washing machine microplastic discharge.
None of these are dramatic in isolation. Accumulated over years, repeated daily, the picture is worth a considered look.
The Same Question, Applied to Clothing
DEVOTED started with the shaker because it was the highest-frequency food-contact variable a gym-goer could change. The clothing question applies the same logic to a different variable: what is the best possible material for something that's in direct contact with your body's largest organ, for most of your waking hours?
We're working on the answer to that question. It's the same standard as everything else we build.
Sources
- University of Birmingham, April 2024. Published in Environment International. First experimental evidence of chemical additives in microplastics leaching through skin via sweat. Found up to 8% uptake through sweat-moistened skin. URL: https://www.sciencedaily.com/releases/2024/04/240419131901.htm
- Zambrano, M.C. et al. "The contribution of washing processes of synthetic clothes to microplastic pollution." Scientific Reports, 2019. Found synthetic garments release between 640,000 and 1,500,000 microplastic fibres per wash cycle depending on garment type and construction. URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6488573/
