"In winter, people and animals sleep more, stay indoors, and rely on their stores of food and fuel to get them through this season. There is a minimum of daylight and the natural cycle is to turn inward and hibernate. (In this age, of course, most people consider seasons irrelevant, so we're unlikely to see much hibernation going on.) One of the best ways to stay healthy is to be in tune with the dynamic of the season. This time of year that means going to bed earlier, being a bit less active, and rejuvenating yourself to be ready for spring.
Don't be discouraged if you have less energy in the winter -- there is less energy around you -- use what you have wisely. Finally, take this lesson beyond the current season. The energy of water is not only present from December to March -- there should be a 'winter' in every day and at the end of every project you take on -- the period of rest and stillness, of turning inward and taking inventory. This phase is a vital part of life and longevity, and yet it is probably the most neglected in our modern lifestyle."