Closing and storing

The three months of Winter are called the period of closing and storing.
Water freezes and the Earth cracks open.
One should not disturb one's Yang.
People should retire early at night and rise late in the morning and they should wait for the rising of the sun.
They should suppress and conceal their wishes, as though they had no internal purpose, as though they had been fulfilled.
People should try to escape the cold and they should seek warmth, they should not perspire upon the skin, they should let themselves be deprived of breath of the cold.
All this is in harmony with the atmosphere of Winter and all this is the method for the protection of one's storing.

From The Yellow Emperor’s Classic of Internal Medicine, translated by Ilza Veith (Berkeley, 1966).