Summarize this article:

Winters are hard on people: long nights, not much sunshine. It's not an easy task to look bright and fresh every day. Get a lot of sleep and when you're unable to do it,  take advantage of the weekend and get some rest.  Try to enjoy the sun when you can find some!- and fill the lack of it by taking vitamin D. Add vitamin C for energy! Cure your colds with adequate remedies and by staying warm. Healthy doesn't mean boring, protected and cloistered. Keep up with some exercise and go for walks, go downtown and hang out with your friends, try not giving up on your hobbies...  Maintain a social life. Winter is a tiring season, so make compromises. For instance, having a fun going out on Saturday and staying in on Sunday will keep you both rested and happy. Enjoy the winter pleasures––snowballs fights, winter sports, Christmas shopping, etc. Try to stay in an optimistic state of mind. Don't forget: a happy person shows her beauty on her face and will glow through the coldest winters!

Summary:
Maintain a healthy lifestyle. Have fun with the season.