3 Supreme Performance Base Layers Reviewed and Compared: Patagonia Merino Air, Compressport On/Off, Craft Active Extreme

Staying comfortable in cold, wet, and windy weather is tough to do especially if you not only encounter all these conditions but all of a sudden the sun beats down hard. The simple tech top can do a good job in many conditions but is often loose and clammy when the wind picks up. These 3 base layers  Patagonia Merino Air, Compressport On/Off, Craft Active Extreme represent the best I have seen in recent years as the apparel "arms race" heats up. Their prices match their supreme performance...

Compressport On/Off Image Compressortusa.com

Compressport On/Off Image Compressortusa.com

The Swiss designed, European made Compressport On/Off Multisport is great in wet cold weather which can change to heat, say during an Ultra.  I have not tried it in winter cold as of yet.  It absorbs little water , is made of a very soft, comfortable stretchy very lightly compressive fabric, and has strategically placed mesh vents and compression, all knit from the same fabric, seamlessly. I wore this top at Boston this year in windy, wet cold conditions under a very light shell and it was perfect. I was comfortable the whole way while many suffered.  I have also worn it in hot conditions above 80 and the damp microclimate it creates never gives one the sense of over heating or that much clamminess, and actually seems cooling The longer arm coverage is particularly cooling in sunny conditions.
Here is what Compressport says about the compression and venting of the On/Off, a mouthful:

"On for maximum ventilation during acceleration phases.

Compressport provides the first shirt whose interactive On/Off fibers breathe with you. Its 42,000 breathing alveoli open and let in the air you need to perform. Your breathing then becomes regulated depending on the intensity of your workout. You can breathe deeply, with no limits.

Off for high-pressure protection during deceleration."

Not sure how effective the compression elements are but they are in any case pleasant. Hopefully my posture and alignment is better. It just may be...
I have the mid length sleeve model (MSRP $95 on sale $75 now)  but it also comes in  long and tank styles.  The On/Off is very stink proof, even after multiple runs. Now the style it is a bit, how should I say, bionic, with the variable knit venting and compression and tight fit maybe not great if one has a little extra around the midsection as I do... But who cares if it works and it does.  The Compressport Calf Sleeves R2  ($50)  are also outstanding, very light soft and effective (for me to reduce the chance of calf cramps due to vibration) while also comfortable. Now the colors and branding might be toned down, below I actually have the compression sleeves inside out to lose the logos....Compressport is a major player in European trail running and triathlon apparel.

Patagonia Merino Air Crew

Patagonia is a careful company where performance, sustainability, and style are always top priorities. Patagonia Merino Air is made of a blend of South American Merino and Patagonia's signature Capilene synthetic base layer fibers. The innovation is in bulking up the fibers to create not only loft for warmth but increased surface area and depth for breathability and drying. The process also makes the garment incredible light. The garment is knitted and completely seamless. 

Some friends have already said it looks like a sweater and it does, sort of like a "golf" sweater, a sport I don't do. Don't be fooled as while "warm" when it needs to be under layers in cold,  it has also  performed incredibly well for me standalone in warmer temperatures, 50F and under a breathable Windstopper shell. Very little moisture or wet, even under a shell. I have not yet tested in rainy conditions to see how saturated it gets and what that feels like. And when you are done with your workout it can do double duty as that stylish sweater as you have a post workout beer without the usual post run chill. In fact my running group thought I had changed into a sweater. Super comfortable against the skin, very stretchy and soft but not constricting.

I tested the Merino Air on several runs in very moderate temperatures and also this weekend on a hike in the White Mountains of New Hampshire.

Mount Pierce NH with Mount Washington in the background

Temps down below were in the 30's, damp, icy and dark with a 2500 climb over 3 miles. I stayed remarkably dry, almost no moisture on the back with the Merino Air under my favorite Salomon S-Lab Motion jacket. At the ridge there was warm sun and no wind. The jacket came off and I hiked the rest of the way in complete, dry comfort no chill back in the cold woods below. Remarkable for this heavy sweat-er. I can't wait for deep cold runs in this top! Very pricey but supremely versatile. Highly recommended. 

Women's Merino Air Hoody

I have the crew ($129). Air Merino is also available in a hoodie ($149) and long bottoms ($129) for both men and women. All the styles, exclusively from Patagonia this season, are available here

Craft Active Extreme 

Craft is well known for their running, cycling, and especially Nordic ski apparel. The US Nordic Ski Team races in Craft suits. I have had a couple earlier Craft Extreme tops. They performed extremely well but were very snug, not very stretchy and not particularly soft on the skin. The Active Extreme is far softer and stretchier and still has Craft's signature ribs design to increase loft and surface area for moisture evaporation. It fits snuggly but far more comfortably than the prior versions which were often a bear to pull off.

I ran the Mount Desert Island Half in the Active Extreme with the start at 29F and finish at around 50F and was perfectly comfortable throughout. More focused on cooler temperatures, than the Compressport it is a fine standalone top down to freezing if there is no wind and a great base layer under a shell and potentially insulation when the temperatures drop below freezing. Recommended

At $75 they are the "bargain" of the three tops. Available from Running Warehouse for men here and women here.

Conclusions and Recommendations

These 3 fine base layers each seem to have particular strengths based on my evaluation and their specs:

• Compressport  On/Off for wet, windy, cool conditions as well as hot conditions
• Craft Active Extreme great as a form fitting base layer for breezy cool without a wind layer and cool to cold conditions under other layers
• Patagonia Air Merino: outstanding cold weather performance and breathability due to its lofted construction under jacket or other layers and great also standalone in cool conditions where breathability and rapid drying is sought.