I wrote this article for a specialized health group. I am sharing it here so that other people may benefit.
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In qigong, heat escapes the body through the 5 main points. Namely, the two feets, two hands, and the head. If you keep these points well encapsulated during the cold season, it will go a long ways to keeping your body full of qi (and thereby qi) and your immune system strong. A strong diet is not good enough, You need to wear gloves, winter socks, and a cotton hat. This will help protect your qi. Of course, wearing a good coat is important to protect the body when you are out in the cold.
While what I say may not seem too enligtening, did you know that it is hard to to go sleep at night when your feet are cold? Try washing your feet with cold water at night before going to bed and see how long it takes you to fall asleep. Conversely, wash your feet with nice warm ionized acid water and see how easier it is to fall asleep.
In the cold season, I like to wear socks in the house and to bed. This will keep me much warmer than say using an extra blanket and turning the heat up. Of course organic cotton is the best but a nice quality sock would do wonders, as it does for me.
The main thing is to protect the five qigong points, if you want your qi to be strong during the winter. Of course, that entails wearing gloves when you go outside in the winter instead of trying to 'tough it out' and trying to prove that you don't need it. You may just prove yourself right and win the battle but those the war in the winter season for your qi health.
Your qi health and overally life energy is very dependent on how you protect qi and nourish your qi. Good dietary practices is only half of it. You may already know by now that even with the best diet, you don't have the abundance of energy you would like. Diet alone won't solve this problem though it will help if the diet is poor.
Did you know that if you walk on the cold floor constantly in the winter with your bare feet, that you are losing qi through that? While you may feel that it won't affect your health at all, you may also notice you don't have the abundance of energy you would like. They are related. Your health and energy level is dependent on how much qi you have nourished, transformed, and stored.
Your energy level is dependent on the quality qi you have stored.
Make sure that you wear a nice quality hat/cap and not a baseball cap. Most baseball caps are worn too tightly and block the qi circulation in the head. Did you know that wearing a cap too tight for 10+ years can stop the qi from circulating properly in the head and you may develop patterns of baldness? Or the quality and vitality of your hair may not be what it used to be.
Of course in the spring and summer it is different. You actually want to absorb some of the nice qi flowing around and you don't want to wear gloves.