Choose the Right Layer: Down vs Synthetic vs Merino vs Fleece

December 12, 2025

When Comfort Makes or Breaks Your Performance.

Picture this: You’re charging up a switchback trail, dropping watts on a gravel climb, or pacing through frigid pre-dawn miles — but something’s off. You’re either overheating, soaked in sweat, or freezing the moment you stop. It’s not your fitness. It’s your layering.

In high-output outdoor sports like cycling, running, hiking, skiing, or snow adventures, what you wear can make or break your day. Choose the wrong fabric, and you’re battling your gear instead of the trail. Choose the right one, and you’ll move faster, stay out longer, and recover quicker.

This guide breaks down the four key fabric types—down, synthetic, merino wool, and fleece— and compares their performance across intensity levels, weather conditions, and sport-specific needs. We’ll show you how to put this knowledge to use with curated gear highlights from our collection.

1. Down Insulation

Down is unbeatable for retaining warmth during low-movement periods — think standing around at trailheads, taking ski breaks, or warming up after a hard effort. It’s not ideal for running or cycling, where sweat buildup can compromise loft and warmth.

Best for: Low to moderate intensity, cold/dry conditions
Ideal sports: Après-ski, winter hiking, recovery wear

Pros:

Exceptional warmth-to-weight ratio
Highly packable
Long-lasting (with proper care)

Cons:

Poor performance when wet
Overheats during high-output activity
Requires special cleaning

2. Synthetic Insulation

Synthetic insulation thrives when you’re moving in cold, damp conditions. Whether you're skinning uphill or riding in freezing fog, synthetics keep you warm without collapsing under moisture—a great middle-ground option for stop-and-go exertion.

Best for: Moderate to high intensity, variable/wet weather
Ideal sports: Ski touring, winter cycling, alpine hiking

Pros:

Retains warmth when wet
Dries faster than down
Often more affordable

Cons:

Heavier and bulkier than down
Less packable; doesn’t compress as small as down
Less breathable than natural fibres

3. Merino Wool

Merino excels in high-output endurance sports, such as cold-weather running or cycling, where sweat management is crucial. It's a go-to for base layers, offering warmth without bulk and staying comfortable over long distances. Ideal for runners and cyclists who refuse to slow down.

Best for: Base layering in cool to cold conditions, high-output activities
Ideal sports: Running, cycling, hiking, ski touring

Pros:

Naturally breathable and moisture-wicking
Regulates temperature extremely well
Odour-resistant (multi-day wear approved)

Cons:

Can be expensive
Less durable than synthetics
Slower to dry

4. Fleece

Fleece is a dependable mid-layer when breathability is more important than extreme warmth. Perfect for layering under a shell on shoulder-season hikes or wearing solo on dry winter runs. For high-output sports in dry and cold conditions, fleece adds warmth without overheating.

Best for: Mid-layer warmth in dry or active cold conditions
Ideal sports: Hiking, casual skiing, shoulder-season adventures

Pros:

Breathable and fast-drying
Durable and easy to care for
Affordable warmth

Cons:

Not wind or water-resistant
Bulkier than other options
Can retain odours

Gear Up: Explore Our Performance Picks

Ready to upgrade your layers? Here are a few standout pieces from our latest collection:

Merino Base Layers for High-Effort Days
Ultra-soft, lightweight, and built for movement. Perfect for cold runs or rides.
👉 Explore Merino Collection
Synthetic Insulation for Wet and Wild Adventures
Lightweight warmth that keeps working even when soaked. A backcountry must.
👉 Shop Synthetic Jackets - Men’s | Women’s
Down for Cold Recovery Moments
Packable, premium loft that keeps you warm when the sun goes down or the lift line grows.
👉 Browse Down Insulation - Men’s | Women’s
Fleece for Everyday Adventure
Reliable warmth that works from trail to town.
👉 Check Out Fleece Essentials - Men’s | Women’s

Conclusion: Don’t Let Your Layers Hold You Back

In the outdoors, comfort is performance. The right fabric choice can mean the difference between powering through and calling it early. Whether you're pushing watts, logging long miles, or tackling vertical, your gear should work as hard as you do.

By understanding how down, synthetic, merino, and fleece perform — and matching them to your activity intensity — you’ll stay dry, warm, and focused. No distractions. No compromises.

Gear up with intention. Go faster. Stay longer. Move smarter.