that will change the way you see your activewear.
4 min read (or one spin of The Sugerhill Gang's Rapper's Delight)
3 things
We’re constantly looking for ways to improve performance. Balancing macros, staying hydrated, sleeping well, refining recovery.
We pay attention to mindset. Ice baths. Nasal breathing. Always chasing that extra edge.
But how often do we think about what we’re wearing?
Whether you’re an Olympic athlete or just staying active, the goal is the same: more comfort during training.
And comfort isn’t just how something feels. It’s how it performs. Especially when it comes to temperature.
The truth is, your clothing plays a bigger role than you might think.
With most activewear made from plastic-based fabrics, it’s probably time to take a closer look.
So, plastic vs natural. Let’s look at the science.
01 | Regulating Body Temperature: Why Breathability Matters
Here’s a simple starting point: for every 1°C increase in body temperature, you lose around 5% of your power.¹
Your ideal skin temperature sits around 33.4°C. As your core temperature rises during exercise, performance drops.
By the time you feel overheated, it’s already happening.
Your body regulates temperature by moving heat away from the core. That heat needs somewhere to go.
This is where fabric matters.
A good performance fabric should allow heat to transfer from your body to the air around you.
Polyester doesn’t do this well. It traps heat, making it harder for your skin to breathe. It’s a good insulator. That’s why it works for ski wear. But for training, it works against you.
Natural fabrics behave differently.
Bamboo, for example, is highly breathable. It allows both heat and moisture to escape, helping you stay cooler for longer.
Studies have shown bamboo fabrics allow air to pass through at roughly twice the rate of cotton.²
Why does that matter?
When you train, your body cools itself in two ways:
Sweating (evaporation), and
Redirecting blood to the skin to release heat.
The catch is this:
The more blood used for cooling, the less is available for your muscles.
Performance drops. It’s not far off the feeling of training at altitude with less oxygen.¹
If your clothing traps heat, your body has to work harder to compensate.
Breathable fabrics reduce that load.
02 | The Problem with “Permastink”
You’ve probably experienced it.
Freshly washed kit. Still smells.
That’s not you. It’s the fabric.
A study from the University of Ghent found that the bacteria responsible for body odour thrives in synthetic fabrics like polyester.
These fabrics trap sweat, creating a warm, damp environment where bacteria grows. Washing doesn’t fully remove it, so the smell lingers.
Some brands try to fix this with antimicrobial treatments. Often that means adding chemicals like silver nanoparticles.
Not great for the environment. Not great for your skin.
Natural fabrics take a different approach.
Wool, hemp, and bamboo naturally resist bacterial growth. One study found over 70% of bacteria on bamboo fabric was eliminated.³
Fewer bacteria means less odour.
Simple.
03 | Inflammation, Allergies, and Skin Irritation
This is the part most people don’t consider.
Polyester is made from petrochemicals. And those chemicals don’t always stay locked in the fabric.
When you sweat, your skin becomes more absorbent.
Studies have shown that chemicals in synthetic fabrics can pass through the skin and into the bloodstream.⁴
Sweat can actually accelerate this process, helping dissolve and carry substances into the skin.⁵
Over time, repeated exposure can lead to build-up in the body.⁶
In 2023, the Centre for Environmental Health in California issued notices to most of the major synthetic activewear brands after finding high levels of BPA in their clothing.
BPA is used in polyester to improve durability. It’s also a known hormone disruptor.
Their advice was simple:
Reduce exposure to synthetic activewear. Remove it after training. Or switch to natural fibres like cotton, bamboo, hemp, or wool.⁷
Conclusion: Comfort is Performance
The goal of training is simple. Move better. Feel better. Perform better.
Regulating your body’s temperature and reducing unnecessary stress on the system is part of that.
And that starts with what you wear.
Comfort might sound small. It isn’t.
It’s performance.
"Dress good to look good. Look good to feel good. And feel good to run fast."
Florence Griffith-Joyner, Olympic Sprinter
So if you want to feel better and get more from your training, the takeaway is simple:
Choose your activewear carefully.
¹ Racinais, S., Périard, J. D., Karlsen, A., & Nybo, L. (2015).
² Prakash, C., Ramakrishnan, G., & Koushik, C. V. (2013).
³ Badr, A. A. (2018).
⁴ Iadaresta, F. et al. (2018).
⁵ Matei, A. (2023).
⁶ Abafe, O. A. et al. (2023).
⁷ Carnevale, S. (2023).