Vapor barrier layers—whether or not purpose-made or improvised from plastic baggage—sound like a recipe for sweaty canine. However in chilly climate, they could be a lifesaver.
Point6’s model of the vapor barrier layer (Photograph: Courtesy (sock); Allison Saeng/Unsplash (background))
Revealed January 20, 2026 11:03AM
It appears like a kind of hypothetical survival situations: Would you relatively have moist socks or put on plastic baggage in your toes? But many hikers swear by vapor barrier liners (VBLs) of their boots. These impermeable layers, usually made from plastic, separate your pores and skin out of your sock and prevents moisture absorption. In winter situations, they are often remarkably efficient.
“If I wrap my toes in plastic baggage in the midst of summer time and go for a run, I’m going to have swamp toes. It’s a completely horrible thought,” says Justin Simoni, a guidebook creator and long-distance athlete based mostly in Boulder, Colorado. “Issues are a bit of bit totally different when it will get very chilly. Then you definitely actually wish to watch out of how a lot warmth you’re dropping.”
Consider your toes on a winter hike. As you get going and heat up, you begin to sweat throughout your physique, together with in your boots. And the place is all that sweat going? In all probability into your socks.
In fairer winter temperatures, your sweat strikes away from the physique, by means of your socks and footwear, and dries within the ambiance by way of evaporation. Nevertheless, in temperatures under 30 levels, sweat evaporates rather more slowly—if in any respect—and the insulative layers (socks, on this case) designed to maintain you heat can keep moist and chilly.
On a dayhike, moist socks might be uncomfortable. On an overnighter, waking up with moist socks might be devastating. In case your toes don’t heat up, you could possibly be in your solution to frostbite.
That’s the place a VBL is available in, trapping perspiration and making a microclimate towards the physique. In contrast to waterproof-breathable materials, neither water nor air can escape VBLs.
Some manufacturers, like Rab and Point6, promote vapor barrier socks. Some hikers use neoprene socks. However the least costly and best to search out possibility are trash baggage, bread baggage, or grocery baggage. Simoni’s VBL of selection is a turkey bag.
For those who don’t like plasticky materials straight towards your pores and skin, you possibly can put on a skinny liner ideally wool, then the VBL, then your socks, after which your footwear of selection.
By trapping your sweat and physique warmth with a VBL, you lock in heat. Simoni provides, “You lose just a bit bit of warmth out of your perspiration, from that water vapor leaving, so in case you can entice that perspiration, you’re mainly going to get hotter.”
Different advantages: Your sweat received’t drench your socks. Protected by the VBL, your socks will keep dry—so long as you don’t wade by means of a stream or get snow caught in your boot. Some hikers even report blister prevention as a result of VBLs reduce down on friction.
And perhaps most helpful of all, you’re all the time keenly conscious of how a lot you’re sweating. If sweat is pooling within the plastic baggage in your toes, it’s an indication to regulate your whole layering system.
One draw back to pay attention to: As skinny because it may be, a VBL can add bulk in your boots and also you run the chance of compressing your insulative layers down or creating stress factors.
Simoni suggests testing out a VBL in a low-stakes situation, akin to a dayhike and even driving a chairlift, when you recognize you’re going to be uncovered to the chilly however can simply bail. Begin by carrying the VBLs, but when issues don’t go effectively, swap into an additional pair of socks you packed.
When you get used to carrying VBLs, their use instances are many. Simoni all the time retains just a few turkey baggage in his pack simply in case situations get too chilly—akin to when he’s biking from his house in Boulder to the 14,259-foot Longs Peak to climb it, an journey he’s achieved nearly 50 occasions. This winter, he’s bringing his trusty turkey baggage alongside on an try of the Nolan’s 14 Route in Colorado’s Sawatch Vary, the place he’ll recurrently sleep at 10,000 toes.
So going again to the survival hypothetical: Which is it for you? Moist socks, or plastic ones?
