Whether you're tackling a steep mountain trail, heading out on a weekend hike, logging kilometres on the road, or simply enjoying an active day outdoors, staying comfortable can make all the difference. Too hot, too cold, or drenched in sweat, and your performance starts to suffer.
That's where 37.5® Technology comes in.
Designed to help your body maintain its ideal comfort zone, 37.5® is one of the most advanced fabric technologies available today. Featured in selected First Ascent performance apparel, it's built to keep you comfortable across changing temperatures and varying activity levels.
What is 37.5® Technology?
The name comes from the body's ideal operating conditions:
- 37.5°C – your ideal core body temperature for peak performance.
- 37.5% relative humidity – the optimal humidity level next to your skin to stay comfortable.
Unlike traditional moisture-wicking fabrics that simply move sweat across the surface of the garment, 37.5® Technology works before sweat even forms.
Using naturally derived active particles made from volcanic minerals and activated carbon, the fabric attracts moisture vapour and speeds up evaporation, helping regulate your body temperature before you become hot, clammy or cold.
How Does It Work?
As your body begins to heat up, it releases energy in the form of infrared radiation. The active particles embedded permanently within the fibres use this energy to remove moisture vapour from the microclimate around your skin.
The result?
- Faster evaporation
- Better temperature regulation
- Less sweat build-up
- Improved comfort during activity
Because the particles are permanently embedded into the fibres, the technology won't wash out or lose effectiveness over time.
Why It Matters Outdoors
South African adventures rarely stay the same from start to finish.
A chilly morning can quickly become a scorching afternoon. A steep climb can have you working hard one moment before stopping to enjoy the view the next.
37.5® Technology adapts with you by helping your body manage changing conditions naturally, making it ideal for:
- Hiking
- Trail running
- Mountain biking
- Multi-day trekking
- Travel
- Camping
- Everyday active wear
Key Benefits of 37.5® Technology
Stay Cooler When You're Working Hard
Instead of waiting until you're soaked in sweat, the fabric begins removing moisture while it's still in vapour form, helping reduce overheating.
Stay Warmer When You Slow Down
Wet clothing cools your body rapidly. By keeping you drier, 37.5® helps reduce post-activity chills during rest stops or changing weather.
Dries Faster
Whether you've worked up a sweat or washed your gear after an adventure, garments featuring 37.5® Technology dry significantly faster than conventional performance fabrics.
Helps Reduce Odours
The active particles also help trap odour molecules, releasing them during washing so your gear stays fresher for longer.
Long-Lasting Performance
Because the technology is built into the fibres rather than applied as a finish, it continues performing throughout the life of the garment.
First Ascent Gear Featuring 37.5® Technology
If you're looking to upgrade your layering system, First Ascent offers several garments featuring 37.5® Technology, including:
- Performance Baselayer Long Sleeve
- Performance Baselayer Vest
- Premium 37.5® Baselayers
- Thermo-Adaptive Jackets
These garments are designed to regulate temperature, manage moisture and keep you comfortable whether you're training, hiking or exploring the outdoors.
Is 37.5® Worth It?
If you've ever finished a hike with a soaked base layer, struggled through changing temperatures, or wished your clothing could keep up with your pace, the answer is yes.
Comfort isn't just about feeling good—it's about performing better, staying focused, and enjoying every kilometre of your adventure.
By actively regulating temperature instead of simply managing sweat, 37.5® Technology helps you stay in your comfort zone for longer, no matter where the trail takes you.
When your gear works with your body—not against it—you can focus on what really matters: getting outside and embracing the adventure.