5 Reasons to Ditch Synthetic Activewear

Scientists Are Finding Microplastics in Our Organs

Synthetic fabrics like polyester shed microplastic fibers during movement. Every rep, stretch, movement releases thousands of particles into the air.

When you exercise, your breathing rate increases 10-20x. Microplastics that shed from your sports clothes are inhaled during that time.

Scientists have detected microplastics in:

• Brain — Nihart et al., Nature Medicine 2025
• Reproductive organs — 2023-2024 studies
• Blood — Leslie et al., 2022
• Lungs — Jenner et al., 2022
• Placenta — Ragusa et al., 2021

Reproductive health: Microplastics have been found in all testicle samples analyzed (2024). Studies link these particles to decreased sperm mobility and disrupted testosterone pathways.

Cardiovascular risk: New England Journal of Medicine tracked 257 patients post-surgery. Those with microplastics in artery plaques had 4.5x higher risk of heart attack, stroke, or death within 34 months.

Respiratory risk: Textile workers exposed to synthetic fibers show higher rates of interstitial lung disease and chronic respiratory symptoms.

Other studies show microplastics trigger inflammatory pathways, oxidative stress, barrier disruption in gut, blood-brain and placental tissues, and metabolic dysfunction.

Your Gym Clothes Are Soaking You in Forever Chemicals and Heavy Metals

Most polyester activewear is treated with PFAS finishes for a "sweat-beading" effect.

Higher PFAS exposure correlates with:

• Weakened immune response to vaccines (NCBI, ATSDR)
• Elevated cholesterol (ATSDR)
• Kidney and testicular cancer (ATSDR)

Antimony is a toxic heavy metal residue that's permanently fused into polyester fibers. The EU classifies antimony trioxide as a suspected carcinogen (ECHA). Higher exposures are linked to cardiovascular changes and organ irritation (ATSDR).

Your gym clothes shouldn't come with a chemical exposure warning. But that's exactly what 99% of brands are selling today.

Toxic Dyes in Polyester Cause Skin Allergies

Polyester is often colored with disperse dyes (also called azo dyes), and dermatology studies repeatedly flag these synthetic colorants as leading causes of textile-related skin allergies.

Some disperse dyes are so toxic they're banned by OEKO-TEX® standards for being carcinogenic or allergenic.

Yet brands rarely disclose which specific dyes they use, so you never know which toxic colorants are sitting against your skin during workouts.

Your Polyester Clothes Are Poisoning the Planet

Textile washing is responsible for 35% of ocean microplastics globally (IUCN, 2017).

Every time you wear, wash, or dry polyester clothing, it dumps plastic straight into the environment. These microfibers never just disappear. They flow through treatment plants, rivers, and oceans, where fish and shellfish ingest them.

Multiple studies now document microplastics throughout commercial seafood (PMC, 2022). A 2024 analysis found 110,000 to 400,000 nanoplastic particles per liter of bottled water (PNAS).

Polyester Hosts Colonies of Stink-Producing Bacteria

That sharp, unclean smell in your gym clothes that won't come out? It's not just sweat. It's bacteria that live inside polyester fabric.

Scientists found that polyester smelled significantly worse than cotton after having people wear them during exercise (Callewaert et al., 2014).

The reason is simple: polyester attracts Micrococcus bacteria, the exact microbes that create that unmistakable "gym shirt" stench.

This Is Why We Built VELM

The body of every VELM garment is made from natural fibers. TENCEL™ Lyocell, non-mulesed merino wool, organic cotton. No PFAS. No hormone disruptors. No azo dyes. Every fabric is OEKO-TEX® Standard 100 certified for skin safety.

Natural fibers that regulate your temperature, resist odor without chemical treatments, and biodegrade at end of life instead of shedding plastic for centuries.

Activewear that works with your body instead of contaminating it.

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