Why professional athletes are going back to wool

Nature has, since time immemorial, provided us mammals with structurally complex, protein-based fibres: wool, cashmere, alpaca, camel hair, mohair and hair. Evolved over millennia, these natural fibers have a pretty vital job: keeping us comfortable as we move through our days, deal with temperature swings, and navigate the changing seasons. Each natural fibre is designed to fulfill the specific needs of its ecosystem.

Take the alpacas. Adapted to live in the unforgiving mountainous climate of the Andes, alpaca wool is a thermal insulator even when wet, does not retain water, and it’s lighter than the wool that comes from merino sheep, for instance. Then look at the desert camels. Camels’ hair allows them to survive the desert’s brutal extremes, and their two-layered coat features a soft, insulating undercoat that can absorb up to 30% of its weight in moisture without feeling damp. 

As for our own species? Well, humans have historically turned to the natural fibers available in their immediate surroundings. What our ancestors understood intuitively, science is now confirming: natural fibers outperform their synthetic counterparts in crucial ways. Because there’s no artificially created fabric that can nail the major properties of natural fibers - thermal insulation, moisture control and breathability - as dynamically as wool can. 

Dynamic and breathability are the key words here 

Because it’s not only a matter of static warmth (thermal insulation) or keeping moisture at a minimum. It’s about the constant movement between activity and rest. Hikers, skiers, cyclists, runners, rock climbers know this pain most intimately, as their activities have bursts of what’s known as “exothermic heat generation” of the sweating phase and the ”evaporative cooling” of the drying phase: in other words, “stop-go” activities. 

Woolmark, the global authority on everything wool, published the findings of revealing research on the dynamic breathability of natural fibers, particularly that of wool. Conducted at North Carolina State University over four years, the study tested five fabrics made from merino wool, cotton, polyester, and viscose in stop-go conditions, simulating activities that involve bursts of effort, followed by rest. 

The result? Wool, particularly merino wool, is the winner by far. Wool required half the energy expenditure of other fibers to maintain thermal comfort, and only wool maintained ongoing comfort throughout the resting phase. All other fiber types caused participants to experience "after-chill," that uncomfortable cold sensation when you stop moving. Wool's temperature “buffering” efficiency was 26% superior to viscose, 45% superior to cotton, and 96% superior to polyester.

Source: Woolmark Chart, demonstrating that wool garments maintain infinitely better thermal regulation during the resting phase.

Wool facts:

• Wool can absorb up to 35% of its weight in moisture vapor without feeling wet, then let it evaporate. This breathability keeps skin drier and prevents fabric from clinging to the body.

• Wool responds to changes in body temperature, moving excess heat away from the skin. It can feel up to two times cooler than synthetic fabrics in warm environments. Its thermo-regulating attributes mean that athletes wearing wool waste less energy trying to maintain the thermal balance, which means they have more energy to invest in their sports, or in their competition.

• Each Merino wool fiber contains cortical cells that can bend up to 20,000 times without breaking. This remarkable cellular structure is why wool garments resist wrinkles and maintain their shape over time.

• Since wool is a natural fiber that grows on sheep, it is 100% renewable since a new fleece grows each year, and 100% biodegradable: when disposed of, wool biodegrades in soil within a few months, returning nutrients to the earth.

Our Rest and Recover TechFleece program is built around wool for a reason: it excels during warm-up and cool-down. Made from 100% Merino, the TechFleece keeps muscles warm when they need it and wicks moisture without the after-chill, making the hoodies, joggers, and jacket ideal for pre- and post- workout comfort.

Designed for stop-and-go activity, our 100% merino wool base layers, t-shirts, and merino fleece range offer unmatched performance in outdoor sports - lightweight, protective, and continuously regulating your temperature as you move.

When athletes are switching back to wool, it is not about making an ecological statement, though that is a welcome effect. It is, simply put, about choosing wool because it works better. Because when they are out there moving, sweating, resting, and moving again, wool is the only fiber that keeps up with the body. Wool does not just perform well in a lab test. It performs out in the real world, where it’s most important: on the trail, on the skis, on the bike, on the mountain.