Feeling cold during still meditation is very common. In moving Qigong you energize your body, so it is warm and more Yang. But in still meditation you calm your mind and slow your breathing, reducing your heart rate and making your body more Yin. In the winter, your body releases energy into the surrounding air more quickly than in the summer, and feeling cold can be more of a problem. So when you meditate in the early morning or in the winter, wear warm clothes and cover your legs, especially your knees, with a blanket.
Sometimes you feel cold even when warmly dressed and with the room at a comfortable temperature. This is most likely caused by your mind, which significantly influences Qi circulation in your body. Sometimes you may feel cold when nervous tension, emotional upset, or fear send a sudden chill through your body. Since your mind has such an effect on you, it is important to regulate it through meditation. You may also feel some part of the body suddenly colder or warmer. This is a common experience as Qi redistributes during deep relaxation, so do not be too concerned about it. Click to learn how Chinese medicine treats Diabetes.