NORTH CAROLINA – A new scientific study has provided fresh evidence that wool base-layers offer superior thermal comfort during outdoor stop-go sports such as hiking, cycling and rock climbing.
The four-year PhD research programme, undertaken at North Carolina State University, compared garments made from 100 per cent wool with cotton, viscose and polyester fabrics of similar weight and thickness.
Researchers concluded that wool’s natural fibre structure enables athletes to maintain a more stable microclimate during alternating phases of activity and rest, a key challenge in endurance and outdoor performance environments.
Stop-go sports involve repeated cycles of exertion followed by pauses or lower intensity movement. During active periods, perspiration builds as the body generates heat. When activity slows or stops, sweat retained in clothing begins to evaporate, often creating a rapid cooling effect that can leave athletes feeling chilled and uncomfortable.
Until now, much of wool’s reputation among outdoor users has been based largely on anecdotal feedback from athletes and apparel brands. The North Carolina State University research sought to test those claims under controlled laboratory and human wear conditions.
Garments were assessed using both sweating thermal manikins and human participants. Researchers also modified laboratory equipment commonly used by outdoor apparel designers to better replicate the dynamic humidity and temperature changes experienced during real sporting activity.
The results showed that wool fabrics demonstrated the strongest ability to manage changing humidity conditions. In simulated testing, wool showed the highest capacity to support transitions between environments of 45 per cent relative humidity and 80 per cent humidity, outperforming viscose, cotton and polyester equivalents.
According to the researchers, this performance is linked to wool’s complex fibre structure. Wool can absorb significant amounts of moisture vapour within the fibre itself while maintaining a relatively dry surface against the skin. At the same time, its naturally hydrophobic outer layer slows rapid evaporation.
This combination appears to reduce sudden cooling during rest periods, a common source of discomfort for athletes wearing other fibre types.
Angus Ireland, program manager for Fibre Advocacy and Eco Credentials at Australian Wool Innovation (AWI), said the findings help explain why wool has remained popular among outdoor users despite intense competition from synthetic performance fibres.
“The combination of wool’s ability to absorb moisture, generate heat and then only gradually release that moisture, together with its hydrophobic outer layer deferring rapid evaporation and cooling, were concluded to be responsible for wool’s dominance,” he said.
Researchers found that wool garments supported improved thermal sensation during rest phases in particular. Maintaining warmth when activity slows is widely considered critical for endurance athletes, as excessive cooling can increase fatigue and reduce performance.
The study also suggests that stable thermal comfort may allow athletes to retain more usable energy during activity. Ongoing research is now examining the scale of this effect and whether measurable performance advantages can be quantified.
Thermal regulation has become an increasingly important area of innovation for outdoor apparel brands as consumer expectations shift towards multifunctional garments capable of handling varied environmental conditions. Climate variability has also intensified demand for clothing that can adapt to fluctuating temperatures and humidity levels within a single activity session.
Synthetic fibres have traditionally dominated performance sportswear due to their durability and moisture transport properties. However, wool’s resurgence in technical apparel over the past decade has been driven by advances in fibre processing, finer micron wool production and increased interest in natural fibres with lower perceived environmental impacts.
The North Carolina State University research adds scientific validation to wool’s thermoregulatory credentials, particularly in mixed intensity activities where managing transitions between sweating and cooling remains a key comfort challenge.
