There's a widespread belief that cotton has no place in the gym. That's an oversimplification. Cotton is the wrong fabric for some training and completely fine for other kinds — and knowing the difference saves you money.
The core difference
Cotton absorbs moisture. Polyester repels it.
Cotton can hold around 25 times its weight in water. When you sweat into a cotton tee, the sweat goes into the fibre and stays there. The shirt gets heavy, clings, and stays wet.
Polyester is hydrophobic. Sweat doesn't soak in — it travels along the fibre surface to the outside of the fabric and evaporates. That's what "moisture-wicking" means.
When polyester is clearly better
High-intensity training. HIIT, circuits, spin, anything where you sweat heavily. A cotton tee becomes waterlogged within fifteen minutes.
Cold weather. This one matters more than people realise. Wet cotton against your skin in cold air pulls heat away from your body fast. For an outdoor winter session, a cotton base layer is genuinely a bad idea — we covered this in what to wear to the gym in an Australian winter.
Anything fitted. Leggings, bike shorts and sports bras need stretch and recovery that cotton simply doesn't have.
Long sessions. The longer you train, the more the difference compounds.
When cotton is fine, or better
Lifting. Weight training generates less sustained sweat than conditioning work, with rest between sets. A heavyweight cotton tee is comfortable, and it doesn't hold odour the way synthetics do.
Walking, mobility and stretching. Low sweat output, so the absorbency never becomes a problem.
Warm-up and cool-down layers. A cotton hoodie over a synthetic base is a good combination — the base handles sweat, the cotton handles warmth and comfort.
Anything you'll wear afterwards. Cotton looks and feels better off the gym floor. Our Essential Cotton Tee is a 7.7 oz cotton built for exactly this.
The odour trade-off
Here's the part that surprises people: cotton smells less.
Odour comes from bacteria feeding on the compounds in sweat. On cotton, sweat is absorbed into the fibre. On polyester, it sits on the surface — much more accessible to bacteria.
This is why a polyester training top can smell after one session while a cotton tee doesn't. Polyester performs better during training; cotton is easier to live with afterwards.
Blends: the practical middle
Most good training gear is a blend, and that's not a compromise so much as a design decision.
A cotton-polyester fleece gets warmth and hand feel from the cotton, and durability and faster drying from the polyester. Our vintage wash fleece is a 53/42 polyester-cotton blend for this reason.
Cotton-elastane blends, like our crop tee, keep the cotton feel while adding the stretch that pure cotton lacks.
Fabric weight matters too
A lightweight cotton tee and a heavyweight cotton tee behave differently. Heavier cotton — 7 oz and above — holds its shape, drapes properly in an oversized cut, and doesn't cling when damp.
Lightweight cotton is cooler but shows sweat marks readily and loses its shape faster.
The practical answer
| Session | Choose |
|---|---|
| HIIT, running, spin | Polyester or nylon |
| Weight training | Either — heavyweight cotton is comfortable |
| Yoga, pilates | Nylon-spandex for fitted pieces |
| Outdoor winter training | Synthetic base layer, never cotton |
| Walking, mobility | Cotton is fine |
| Wearing all day | Cotton |
Shop tees and layers across the men's and women's range at WTD.