I tend to avoid the synthetic blends for next to the skin base layers. This is due to a history of hiking in stinky polypropylene, a fabric that’s long since been updated and sidelined by my current favorite, merino.  I’m currently being charmed out of my hardline preference for natural fibers by Columbia’s new Omni-Heat long underwear. I like this stuff. A lot.

The Omni-Heat line isn’t new to me, I packed an Omni-Heat 3 in 1 parka from Columbia for Antarctica, along with one of their super cute hats. There’s all kinds of information on the Columbia site about Omni-Heat, but essentially, the fabric is dotted with material that reflects your body heat back inwards. In the long underwear, this technology has been applied to a lightweight, stretchy (and stripey) fabric that’s soft and feels quite nice next to the skin.

The long underwear—labeled on the site as a baselayer—-comes in tights and a long sleeved top. Both pieces have the Omni-Heat treatment only where it makes sense. The crotch and inner thighs on the tights and the armpits on the shirt are another Columbia technology , Omni-Wick, designed to move moisture away from your body. Even for those of us that get cold, this makes good sense. Both pieces are anatomically cut as well with gussets match the shape of your body, making the fit super comfortable and easy to move around it. The waistband in the tights is wide and flat and all the seams are flat too, so everything sits nicely as a base layer underneath your jeans (or snow pants, if that’s what you’re wearing.) And yes, guys, this line comes in men’s cuts and sizes too.

I’ve said it before, I’ll say it again. I pack long underwear for almost every destination, regardless of the promised climate. The bottoms can do double duty as leggings under a skirt (nice if you get cold on the plane) and the whole kit works fine as jammies if you need them. You never know what the weather is going to do and long underwear takes up so little space in your bag that it’s worth having a base layer just in case temperatures drop. While I’m a functional person at heart, I liked having a change from solid black. The stripes are cute. I like the way Columbia’s new base layers feel and perform well enough to have packed them (instead of my usual merino) for a recent trip to high altitude  — that’s a firm endorsement from a traveler who’s been committed to natural fibers for the past ten years or so.

You can get Columbia’s Omni-Tech base layers directly from Columbia, the top and the tights are $55-$65 each. Check Amazon, too, (shirt/tights) you may find them for slightly less.