Polartec® Alpha® – A Guide For Shifting Conditions

Performance in motion demands control – not just of your pace, but of your body’s microclimate. Our Polartec® Alpha® series is engineered for precisely that: maintaining warmth and breathability in transitional environments where standard insulation fails.

Designed To Breathe.

Developed originally for U.S. Special Forces, Polartec® Alpha® is an active insulation, a highly air-permeable thermal fabric that continuously releases excess heat and moisture during activity. Unlike traditional synthetic fills or fleece, Alpha® doesn’t rely on static loft to retain warmth; instead, it regulates dynamically, responding to both movement and ambient conditions.

The structure of Alpha® consists of high-loft fibers connected to a stable mesh core, creating consistent warmth without bulk. This open construction allows air exchange even under shell layers, preventing moisture build-up during exertion while still retaining heat when stationary. The result: dependable thermal control through shifting weather and intensity levels.

Our Alpha® fleeces are designed as versatile mid-layers within a modular layering system. Worn beneath a waterproof shell, they excel in cold, wet conditions where breathability is critical. Worn alone, they provide balanced warmth and comfort in cool, dry environments.

Usage Guidance

• High-output activity (hiking, cycling, climbing): Wear the Polartec® Alpha® fleece as a standalone outer layer to manage heat and sweat efficiently.

• Cold, wet conditions: Layer beneath a waterproof shell such as the 3-Layer or Anvil Shell to retain warmth while maintaining airflow.

• Everyday use: The fleece performs just as well on a normal day, making it equally suited for daily wear or travel.

Every detail – from articulated patterning to lightweight hardware – is calibrated for motion. Alpha® insulation performs best when kept close to the body, allowing its thermal regulation to operate in sync with your exertion levels.

Built for endurance, balance, and transition – the Polartec® Alpha® range represents PMO’s approach to adaptive performance wear: protection that breathes, warmth that moves.