If you’ve spent any time outdoors this winter then you know what an adventure it’s been, just deciding what to wear. You’ve learned about layering to the extent that you know enough to bundle up, but on that last hike the cold got to you. Coming home from the trail early, shivering and wet, you start wondering if there’s more to layering than just adding clothes.

You’re right, there is more. You need to know what kind of layers and, more important, when to put them on. If layered correctly, you can have a great time on the trails, keep warm and stay out longer in the bitter cold.

The whole concept of layering is best explained in a few choice words. Dead air space. It’s the space between the layers of clothing, between long thermal underwear and a soft layer of fleece, for example. That space is warmed by your body heat Then the warmth becomes trapped by the next layer and each subsequent layer out to the last.

As you start hiking, skiing or snow shoeing, you create heat that will be contained in those dead air spaces. That’s why if you leave the trailhead with every layer already on, in no time you’ll be wet from perspiration from the inside out. Instead, start off with only the minimum layers, so you need to start moving to become warm. It’s called leaving cold.

If you leave cold, it’ll take longer to soak your inner layer. The wetter you get from sweating the colder you’ll be. Controlling the rate at which you sweat is tricky, because vigorous exercise like hiking causes an increase in perspiration. You can’t stop it except by sitting still. With a wicking fabric next to your skin, the fabric moves the moisture your body has created away from your skin outward so you feel dry.

But even the best wicking material can be overtaxed by strenuous climbing. That’s fixed by leaving additional layers in your pack until you either stop for a break or the summit. Then put on an outer layer and trap all that heat your body’s been generating.

It almost doesn’t matter what form of clothing you use as long as it’s insulating and non-restrictive, and not cotton. Cotton should never be worn in winter, because it soaks, its non-insulating, stays wet and is heavy, making you more wet. Leave the cotton home.

Also if your clothes fit tight, don’t wear them because you’ll increase the amount of perspiration and reduce the amount of dead air spaces. The idea is to keep your body core warm and dry. A layering system could be composed of an inner layer of wicking thermal long underwear, a mid-layer of either a fleece or down vest, a breathable wind shell, and finally a down jacket. One by one, as you add layers to regulate the heat and moisture given off by your body, you’ll stay comfortable during your hike.

This is where breathable fabric earns its money. All that sweat needs someplace to go. A wind shell layer that breathes, like Gore-Tex, gives moisture that’s accumulated in the mid-layers a place to escape. It’s vented away from your body to the outside of the shell.

One of the greatest advances in outerwear design is the invention of pit-zips. They’re to your armpits what hood scoops are for your car. You zip them open while you hike and close them when you stop to trap the heat. Whenever you stop for a half-hour or longer you should also tighten any velcro closures around cuffs or the elastic cords around the bottom of the outer layer to help keep in the heat.

When it’s time to move again, take off that outer layer and once again leave cold. It’s the hardest thing to do, because you just got warm. You’re at the summit, dry and warm with a down parka on and it’s time to go. As soon as you take the parka off you feel cold. That’s how you know if you’re doing it right. Then it’s time to move.

This layering thing is all about moisture management and putting on the right combination of insulating layers at the right time. Controlling the outer layer is easy. The down parka is either on when you stop or off when you hike. In subzero temperatures, simply adding more mid-layers doesn’t help. Instead of two light wool sweaters, wear one medium weight or one heavy weight, depending on how far below zero it gets.

Whatever you choose for a method to stay dry and warm, it’s up to you to find the right comfort range. When the high temperature for the day is predicted to be in the single digits, wear a wool knit hat, balaclava or neoprene face mask. Keep a dry one in the pack for when you stop and you’ll last longer on the summit. Nothing makes you feel warmer than a dry hat when the one you have on is soaked.

Spend a few trips outdoors practicing your personal layering techniques and soon you’ll have it down. You’ll discover when to put your layers on and which materials and designs work best for you. You don’t have to stay inside just because it’s cold. The adventures that are winter are all outside, just waiting to be found. All you have to do is dress for it.

Here’s a reminder for anyone interested in the outdoors and outdoor adventure. Epic Sports in Bangor is sponsoring the Banff Film Festival again this year, but at a new location. This year the evening’s menu of the best of Banff films will be shown at Peakes Auditorium at Bangor High School. The festivities get under way at 7 p.m. this Thursday, Feb 12. Tickets are $8 in advance at the downtown Bangor store or $9 at the door. Seating is limited to 900. Store owner Brad Ryder said the previews for the outdoor films have been awesome.

Brad Viles lives in Ellsworth and is an avid hiker. He can be reached at sball1@prexar.com