If you run or ride a bike outside in cold weather you’ve probably heard that you should wear a second pair of socks to keep your feet warm. Under some circumstances this might be a good idea, but for most people it is horrible advice. Unless your shoes are too big to begin with, a second pair of socks will impede the circulation in your feet—which will make your feet feel colder than they would with just a single pair of socks. Instead of a second pair of socks I would suggest you try sock liners, such as the RedHead ThermoLite Liner Socks.

Many years ago, when I took up cross-country skiing, I used to wear polypropylene sock liners. Polypropylene is a plastic polymer that does an excellent job of wicking water away from the skin, but doesn’t add a lot of warmth. RedHead liner socks are made…