I am reading a book I got at a used bookstore: Organic Body Care Recipes by Stephanie Tourles. She suggests walking every day for 45-60 minutes as part of your beauty routine. This will bring blood and oxygen to your skin, hair and nails. It acts as a natural anti-depressant. She says it’s important to walk in the fresh air and sunshine as much as possible and vigorously enough to work up a good sweat. Sweat cools skin and eliminates waste through your pores.
It's good to know that something that is good for your body is good for your nails as well. I know that I don't walk as much in the winter and see a real difference in my skin. Until now I never linked the two together.