Getting warmer: There are ways to defrost yourself

The true adventurer doesn?t consider a day well spent till he has undergone it in the extremes of discomfort, danger ? and temperatures. Which is why many of you are probably contemplating your next foray into the wilds in the cold light of winter. Not that that can?t be a lot of fun ? if you know how to stay warm at night, when you?re not doing a whole lot else other than sleeping. Use the following tips as your guide to being warm in those long dark hours, and staying that way.

It?s all fluff: Ruffle your sleeping bag before crawling inside. That act of fluffing creates more air space between the fibres or feathers ? air space easily warmed by your body.

Keep ?em on: If the temperature looks as if it will drop below freezing, bring your boots and water bottle into the tent to keep them from freezing. In extreme cold, sleep with your boots and bottle.

Fuel up: Before turning in for the night, nibble on something with high calories. The fuel your body now has to burn will help it stay warmer during the night. Old-timers used to mix a teaspoon or two of butter or fat with a cup of cocoa before hitting the hay.

Double your choices: You can boost the efficiency of a sleeping bag in several ways. By wearing long underwear to bed (a fresh, dry pair), by doubling up in sleeping bags, by using a sleeping bag liner, by sleeping wearing a parka and by sleeping in a tent. Sleeping on a thick and comfortable sleeping pad will also add warmth. Your body will lose more heat to the ground than to the air ? try lying on an unheated waterbed to get the idea. A closed cell foam or foam-filled inflatable mattress is much better than an air mattress.

Seal it in: When the temperature drops unexpectedly and you find yourself shivering in your sleeping bag, put on your rain gear (pants and jacket) to act as a vapour barrier and to hold in your body?s warmth.

Buy the right sleeping bag: To stay really warm, designers generally agree ? with few modifications proprietary to each manufacturer ? that a cold weather bag must have the following features: zipper draft tubers and shoulder collars, ergonomic hoods that cup and insulate without being claustrophobic, and a temperature rating of zero or below (in the winter it is far better to err on the side of warmth).

What insulation do designers prefer? Believe it or not, the response was virtually unanimous. Down is best for weight to warmth ratio and for longevity, and would be the perfect insulation if it could retain its loft when wet. Unfortunately, down is useless when wet. Synthetics are best if you are worried about moisture compromising the insulation: Lite Loft, Primaloft 2, Polarguard HV, Polarguard 3D (more expensive but very soft and lofty) and Lamalite (heavy, stiff and bulky, but it works well even when soaked) are most often mentioned as favoured insulations in winter bags.

How should you buy a winter bag in terms of sizing? Buy it long. Most experienced mountaineers recommend chucking regular-sized bags and opting for bags that offer at least an extra 8 to 10 inches of space at the foot once you?re nestled comfortably inside. That?s so there will be adequate space to store cameras, water, boots and such ?items for which freezing would be a detriment to either you or their performance. In addition, bags with a wider cut can offer more warmth. While a narrower bag (small volume) may be more efficient if you sleep in a single layer of clothes, a wider bag (large volume) will allow you the ability to add clothing to yourself without constricting the bag.