Chinese medicine believes that “Yang deficiency is external cold”, that is to say, the body’s Yang energy is weak, insufficient Qi and blood, Wei Yang is not solid, can not warm the muscles to resist the attack of foreign cold, people are particularly prone to cold. The so-called Yang deficiency body is mainly related to the following factors: 1, iron deficiency. Iron in the body is an important raw material for the manufacture of hemoglobin, which is responsible for the body’s task of transporting oxygen. Iron deficiency reduces the supply of oxygen to peripheral tissues, resulting in impaired energy metabolism of tissues, which can cause the body to feel abnormally cold due to insufficient heat production. 2. Hypotension. Low blood pressure can cause poor peripheral blood circulation, the body does not get enough oxygen and energy, so that people are easily afraid of cold. 3, low thyroid function. Thyroxine has the effect of accelerating metabolism and releasing energy, and it also accelerates blood circulation in the skin, thus increasing body heat to resist cold. If the body is deficient in iodine for a long time and the thyroid gland is not secreting enough, the body will be afraid of cold due to insufficient heat production and reduced ability to resist cold. 4. The incidence of cold fear is significantly higher in women than in men. This is due to the fact that women have less muscle to produce heat than men, and menstruation can easily lead to the loss of iron. In addition, menopausal women are also closely related to the reduction of estrogen levels. Because estrogen can affect the stability of neurovascular function, patients may experience coldness in the hands, feet or the whole body due to poor blood circulation. Second, how to change the Yang deficiency physique and eliminate the feeling of being afraid of cold? The most important thing is to carry out dietary modification and cold-tolerance exercise. The purpose of eating is to take in heat, so every meal should be taken seriously, especially breakfast. Eat more iron-rich foods such as lean animal meat, fish, beans, celery, shiitake mushrooms, dates, black fungus, etc. as appropriate. Eat more vegetables and fruits rich in vitamin C to promote the absorption of iron. You should also pay attention to the intake of iodine-rich kelp, fish and shrimp, jellyfish, oysters, etc., to promote the synthesis of thyroxine in the body. The cold weather often eat some lamb, dog meat and other foods that have the effect of warming the kidneys and strengthening the yang, to improve the ability to protect against the cold is also very helpful. Proper exercise not only strengthens the muscles that produce heat, improves hormone secretion and promotes metabolism, but also helps to transport heat to all parts of the body. Exercise and fitness should be based on each person’s age, physique and environmental conditions, and choose the right exercise program for them. In addition, washing your face, nose and body with cold water every morning can also gradually increase the body’s ability to resist the cold. The best cold exercise, preferably from the summer, should be gradual, persistent. To resist the cold also pay attention to the timely increase and decrease of clothing, which should pay special attention to the head, abdomen and back and foot warmth. The basic principle of dressing is: “the top is slightly thin and the bottom is thick, and the clothes and shoes and socks should be loose and have good warmth”. Should avoid wearing too tight clothing and pants, so as not to hinder blood circulation. For those who are old and weak and have Yang deficiency, TCM doctors mostly use the method of benefitting Qi and helping Yang, using the main formula of Tonic Zhong Yi Qi Tang composed of Astragalus, Ginseng, Roasted Licorice, Radix Angelicae Sinensis, Chen Pi, Sheng Ma, Chai Hu, Atractylodes Macrocephalae, etc., with the addition of Fang Feng and Gan Jiang, etc., which can achieve good results to reduce the occurrence of diseases such as colds. Clinical manifestations of Yang deficiency: frequent fear of cold, lack of warmth in the extremities, light mouth without thirst, or thirst for hot drinks, spontaneous sweating, white face, loss of appetite, hypochondriacal panting, five-shift diarrhea, or thin stools, clear and long urine, impotence, premature ejaculation, lumbar soreness and leg weakness, pale tongue with white fur, sunken and weak pulse, etc. Yang tonic food: chicken, mutton, dog meat, deer meat, pigeon meat, non-vegetable, etc. Yang tonic medicine is common, deer antler, bacopa monniera, bone marrow, seahorse, cordyceps, mealybug, walnut, puzzle nut, eucommia and so on. If the Yang tonic food and Yang tonic medicine stew together to take the Yang tonic effect will be more, or Yang tonic medicine with general neutral food, of course, can also play a Yang tonic effect. The dosage of each tonic should also be understood. For example, many elderly people like to take some deer antler to strengthen the kidney and Yang. It is usually taken 1-3 grams at a time, either as a fine powder to be swallowed, or sliced and stewed in water, or in pills. However, it should not be taken directly into soup. It is advisable to start with a small amount and increase it slowly. It is not advisable to use a large amount suddenly to avoid Yang rising and fire moving or injuring Yin and blood; if you have external fever, Yin deficiency and Yang hyperactivity, you should not take it. Some people may ask if Cordyceps is a Yang tonic? Pharmacologically, it is classified as a Yang tonic. It has the effect of tonifying the kidney and strengthening the yang, tonifying the lung and calming asthma, stopping bleeding and resolving phlegm. And with Yin food such as duck, turtle or Yin tonic medicine, it has the effect of tonifying the Yin of the lung and kidney. So it should be noted that people with Yin deficiency and fire should not apply Cordyceps alone. The general dosage of 3-10 grams in a decoction or stew is preferred. Yang deficiency people can usually cook some mutton porridge or non-vegetable porridge often eat and serve, the effect is also very good. Dietary supplement formula: angelica 30 grams ginger 50 grams lamb 300 grams, often stewed.