For those of us who are training to race (versus year round fitness), we try to go through macro and micro cycles of intensification and recouperation. During the winter, we go into base miles mode, which means a lot of lower intensity, steady, long rides in a purely aerobic zone - that means no sprinting, no going so hard you feel like you're going to keel over, no challenging your friends to a dual on two wheels up a hill. Just steady, mellow, long miles.
It's a time of rest, both physically and mentally. There is something beautifully meditative about a steady aerobic effort. Or, on days when you're feeling a bit cabin feverish in the apartment (like me, today!), it can be mind numbingly monotonous. But, being social as I am, I always enjoy company on the bike. Even when that person isn't riding, and is taking unflattering iPhone photos of me looking sweaty on the trainer in the living room!
Here it is, me at my frumpiest, doing some base miles in the living room in the NYC apartment.