Cotton vs Polyester for Workouts: What the Research Actually Says

Cotton is soft and familiar. Polyester is what most sportswear is made of. But does fabric actually change how you perform? We read the studies so you don't have to,...

Man in a coral red Sportzfit Geo-Mesh tee

Quick answer: Studies find that cotton and polyester tees make no real difference to your heart rate, body temperature or how long you can keep going. Where polyester wins is comfort: it keeps the air next to your skin drier and helps you feel less clammy after a hard session. Where cotton wins is smell. Choose polyester for sweaty training and cotton for easy, low-sweat days.

Walk into any sports store and you'll hear that synthetic fabrics are 'performance' and cotton is for lounging. But is that backed by science, or just marketing? Here's what researchers have actually measured.

Does fabric change your performance?

Surprisingly, not much. In a 2013 study published in Wilderness & Environmental Medicine, eight trained runners ran in a hot room (around 32°C) wearing either a 100% cotton T-shirt or one of three 100% polyester T-shirts. They ran for 30 minutes at a steady pace, then pushed to exhaustion.

The result: no difference in skin temperature, core temperature, heart rate, oxygen use, blood lactate or how long they lasted. They didn't even feel different while running.

An earlier study from 1999 found the same with cyclists in a hot, humid chamber (35°C, 65% humidity): cotton and a cotton-polyester blend performed identically for heat loss and sweat absorption. Riders simply rated the blend as thinner and softer to wear.

So where does polyester actually help?

In the details that affect comfort. In the same 2013 study, the polyester shirts kept the air between the fabric and the chest and back less humid than cotton, both during and after the run. And during the 15-minute cool-down, runners in two of the polyester shirts had lower body temperatures and reported fewer shivering and sweating sensations, that clammy feeling you get when a wet shirt clings to you.

That matches what most people notice in real life. Cotton soaks up sweat and holds it, so a cotton tee gets heavy and stays wet. Polyester doesn't absorb water into the fibre; sweat spreads across the surface and evaporates faster. On a humid day in Mumbai or Chennai, or after a long run, that difference is easy to feel.

Where cotton wins

Smell. A 2014 study from Ghent University found that polyester shirts smelled noticeably worse than cotton ones after a workout, because odour-causing bacteria thrive on them. A 2020 University of Alberta study found that oily body-odour compounds also cling more tightly to polyester and are harder to wash out. (We explain why, and how to fix it, in why your gym T-shirt still smells after washing.)

Which should you wear?

Situation Better choice Why
Running, HIIT, football, long gym sessions Polyester Stays lighter and drier when you sweat a lot
Humid weather or monsoon Polyester Dries faster; less clammy after the session
Yoga, walks, light stretching Either You won't sweat enough to notice a difference
Long days when you can't change Cotton Holds on to less odour

The bottom line

Fabric won't make you faster, and anyone who claims otherwise is overselling. What it changes is how you feel when you're drenched in sweat, and how your clothes smell afterwards. For hard, sweaty training, a lightweight polyester knit is more comfortable. Just wash it the right way.

All Sportzfit training tees and track pants are 100% polyester knits made for exactly this: lightweight, quick-drying and comfortable in Indian heat. Shop the range.

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