After the last blog post about How to Stay Warm in Winter a reader asked that question. And in this winter of unrelenting polar vortices and plunging temperatures, it's an important consideration.
Like hands, feet are more prone to get cold since your body attempts to preserve core body warmth by skimping on blood flow to your extremities. But that's where the similarity between hands and feet stops. Hands get cold because you often expose them directly to cold air as you take off your gloves to use your fingers, and because your fingers have alot of surface area.
Feet get cold because 1) your feet sweat. You may not feel it, but they do; 2) your feet are in contact with the freezing ground; and 3) like skin everywhere on your body, there is an imperceptible layer of moisture that protects the skin and needs to be protected. In order to keep your feet warm, you need to consider each of these.
1) Wear synthetic or the new wool socks. Good brands are Thorlo and Smartwool. I say new wool because in the old days we used ragg wool socks, which have their own set of problems. If you're going to be out for more than a couple of hours, bring another pair to switch into if your feet get cold.
2) If you are someone who can wear liners (some of us get blisters from liners), use a sweat-wicking pair as your first layer. You do not, however, want to wear two thick layers unless your boots are really roomy. Otherwise your feet can be so tight in your boots that your circulation decreases and your feet actually get colder.
3) Boots are your most important decision and what you buy depends on where you live and what you need them for. Like every other piece of clothing, you want your boots to be waterproof but you also want them to be breathable and there is always a tradeoff. Completely waterproof boots will also be completely unbreathable. But in cold and especially wet weather, it's a tradeoff worth making. In that case your best choice is to buy insulated boots that have a removable felt liner that you can take out and dry. Sorels are a common brand. The liner acts as extra insulation, particularly from the ground, and the fact that its removeable means you can dry it out. If you live someplace with predictably cold weather, these are well worth the cost.
But what if you live someplace that isn't ususally cold, it's just this winter (think Mobile, Alabama this morning). It's likely you couldn't find Sorels if you wanted to and you won't need them for long anyway. In that case, take your roomiest pair of boots, put some neatly folded newspaper in the bottom for an extra layer of insulation and then seal them up with a layer of duct tape on the outside. Or instead of duct tape, put a shower cap over each boot. Fashionable? Well sure, in that quirky kind of outdoors way. And definitely functional.
4) Get chemical heaters. These are little packets that you activate by crunching them up and they give off an amazing amout of heat. Do not put them next to your bare skin. But a packet placed inside your boot at the tip can keep your feet warmer for hours.
Remember, keeping your feet warm is not just a matter of comfort but of vital safety. Your feet are very susceptible to frost bite, as evidenced by the number of mountaineers without ten toes. But being adequately prepared can make going out in the cold fun and safe.