One of the questions we are most frequently asked as the outside temperatures begin to drop is, “I am always cold, what is the warmest ** (insert: base layer, fleece, fabric, etc) you have?”. Obviously, there are many answers to this question and personal preference plays a roll so we thought we would take a moment to discuss how your body loses heat in the cold and what you can do to minimize this heat loss.
THE #1 MYTH
You probably know the saying that you lose most of your body heat through your head. But this statement is not completely true. It stems from a study apparently done by the US military in the 50's. Volunteers were dressed in arctic survival suits, but their heads were left bare…you guessed it, they lost the most body heat via their unprotected heads! So, while wearing a hat when outside in the cold is important, it’s not the only body part to pay attention to so read on.
HOW YOUR BODY LOSES HEAT
There are 4 ways to lose body heat:
- Conduction (sitting or leaning or touching something cold)
- Convection (wind chill)
- Radiation (direct heat loss due to exposed skin)
- Evaporation (heat loss by sweating)
And, when your body encounters cold temperatures through any of the methods above, it adapts by constricting blood vessels in the arms and legs, which reduces blood flow to the extremities. This in turn means that your extremities (hands, feet, arms, legs) are going to get colder as they don’t have as much warm blood pumping through them. This may seem counter-productive, but your body does this to keep heat where it's needed most - around your vital organs and brain.
So, knowing these things, we can dress to reduce the impact of a cold environment.
Insulate against the cold. Fortunately, we do this instinctively! If we do it well, we can combat all 4 methods of heat loss and reduce the impact of blood flow restriction.
Tackling Conduction: If our layers are thick enough, we block heat loss by conduction as the coldness of the object can’t get to our warmth and pull it away. Think thin mitts on a freezing cold steering wheel – no good. Nice thick mitts on the same steering wheel will help keep hands toasty as the coldness of the wheel can't pass through the thick mitten as easily.
Blocking Convection: Adding a windproof layer, blocks heat loss by convection as the wind can’t get at our body heat to whisk it away.
Combating Radiation: By building up the clothing barrier (through layering) between our skin and the environment, we help block heat loss by radiation as the air pockets within the fabrics and between the layers trap our body heat. If you are prone to cold hands and feet, wearing wrist warmers and leg warmers, yes…80’s style leg warmers (!) are a great addition. Another tip for those with cold hands is to wear mitts, not gloves, and to make sure the cuff of your mitt is either snug and long enough to tuck well up under your coat sleeve or wide and long enough to easily glide over your coat sleeve ensuring that your wrist does not suffer from exposure because your jacket sleeve and mitt are mashed up and not overlapping. If you’re wearing wrist warmers, it’s great if the outer face of the fabric is smooth and a little slippery so that your sleeves and cuffs slide over easily (overlapping layers = greater insulation). Keeping your neck and face well covered will also go a long way towards staying warm, particularly in very cold conditions.
Fighting Evaporation: If we take care to wear fabrics that are moisture-wicking (especially if we know we will be generating a little heat through movement) we can combat heat loss by evaporation. Moisture wicking fabrics are created to move moisture from the inner surface of the fabric to the outer. Your moisture-wicking base layer, pulls the moisture off your skin. Moisture-wicking mid layers keep moving the moisture away from your body. Performance fabric manufacturers like Polartec®, are constantly striving to create even more efficient moisture-wicking quick-drying fabrics that keep the wearer warm, dry, comfortable and safe because their clothing doesn't stay damp leading to chills or worse, hypothermia, when they are being active in the cold.
PUTTING IT ALL TOGETHER
Here's an example, piece by piece, of dressing for a day of snowmobiling or dogsledding on -25°C day in dry conditions (not a damp cold). Clearly, this is an example for pretty darn cold conditions, but you get the idea. If you are in less cold, more damp, super windy but less cold, etc., you adjust your layers and overtime you have a pretty good idea of what to wear given the day's conditions.
Base Layers: Midweight Long Underwear Pants + Midweight Long Underwear Zip-T Longsleeve for moisture management.
Middle Insulating Layers: 100 Weight (or equivalent) Zip-T Longsleeve + WindPro Vest + 200 Weight (or equivalent) Fleece Jacket on top and 200 Weight (or equivalent) Fleece Pants to add a clothing barrier that will trap body heat and allow moisture vapour to pass through to combat heat loss by radiation and conduction.
Outer Layer: Windproof, Water/Snow Repellent, "Breathable" Parka with insulation that has a loft of about 2" + Bib-style Windproof, Water/Snow Repellent, Breathable Pants (uninsulated).
Extremities: Windproof, Water/Snow Repellent, Breathable Hat with Chin Strap + Aqua Shell Wrist Warmers + Gauntlet-Style Mitts (Windproof, Water/Snow Repellent Outer with about 2" insulation) + Liner Socks (to wick moisture) + Thick Wool Socks + Boots, Polar Buff® Neck Warmer.
Again, the perfect layering system is a personal choice tweaked over time as you learn what works for you and what doesn't in all kinds of cold weather but once you figure it out, you can enjoy the outdoors no matter what nature is throwing at you!