The following text is excerpted from <<Huang Di Nei Jing>>-"Su Wen", Chapter 2 : "Si Qi Tiao Shen Da Lun". Although it is short, it covers the core spirits of how to live healthily in the winter season.
Directly translated as:
"...The three months of winter, they are mean to be covered and concealed, water is frozen and earth is torn, do not disturb the Yang energy, go to bed early and get up late, must wait for the sunshine, keep the mind and spirit inside the heart comfortably, like keeping your private treasures you acquired, stay away from cold and stay warm, keep the skin closed and covered well to protect the Yang energy from leaking out, this is the way of hiding and storing in the winter. If disobey the kidney energy will be harmed and it will not be able to provide energy foundation for spring, there will be tendons related disease and the directions of energy flow will not be right, very little energy for birth will be provided..."
The key words of winter are "hide and store". The word "winter", in Chinese "冬”, also means "the end". After going through the previous three seasons, many plants will fade and die for the winter, and animals will either hibernate or migrate. Human as the "lord of creations" can actively modify the environment and living condition to survive the winter. Besides wearing warm clothes, heating up the house, "hide and store" also means to avoid being overactive and going outside too often.
"...do not disturb the Yang energy.." is the goal and basic requirement of winter health preservation. Yang energy in general is the force of life activities, and in order to preserve it, we need to follow these rules :
"...go to bed early and get up late, must wait for the sunshine...". Go to bed early to avoid the cold energy of night, get up later and wait for sunshine to warm of the cold air from the night before going out for activities.
"...keep the mind and spirit inside the heart comfortably, like keeping your private treasures you acquired...". This is the suggestion from the mental and spiritual perspective. The purpose is the same, to keep and protect the Yang energy. Mental and spiritual activities all consume energy, that's why this statement is brought up to emphasize the importance of cultivating the mind and spirit and its possible impact to the physical body.
When you "...stay away from cold and stay warm...", also "...keep the skin closed and covered well to protect the Yang energy from leaking out...". Here, "keep the skin closed and covered", has two meanings - wear proper clothes, and do not sweat too much or too often. I have mentioned in many articles about sweating being a way of releasing or losing the Yang energy. This brings up an old article I had about my opinions towards exercise in the winter. Every individual is different, I speak for the majority. The bottom line is, find out what type of the health condition do you have before looking for exercises to do.
"...If disobey the kidney energy will be harmed and it will not be able to provide energy foundation for spring...". Kidney is the winter organ and its energy character is "concealing and storing" the primordial and acquired energy. If the Yang energy is disturbed or harmed in the winter it will affect the kidney system first. Without good energy storage in the winter, the kidney system will not be able to provide the vital energy for the body to "birth" again in the spring. If this happens, then:
"... there will be tendons related disease and the directions of energy flow will not be right...". Liver is the spring organ and liver is the "son" of kidney. When the liver system does not receive enough energy from the kidney system it will affect the tendon system (liver is the organ that is in "charge" of the body tendon system). Symptoms can include weakness of tendons and muscle, and impotence. "the directions of energy flow will not be right" generally refers to symptoms of body temperature imbalance or circulation issues, such as cold hands and feet, hot flush, or even fever and flu caused by harmful heat.