I make myself go for a walk outdoors, no matter how lousy I feel, at least four times a week. Whether it's just a walk to campus for a meeting or with the dog, getting out and moving around helps. It forces me realize that there's more to the world than my sad little bundle of miseries. And sometimes I get to see some birds, which makes me happier. It works especially well when the sun is shining, but that's relatively rare - we get 70 days of sunshine per year in my town.

What I really should do is extend that to exercise every day, going out with the dog on her early walk to prime the pump and get my brains and body moving before 7 AM. I know I do better with an early jolt of exercise, but especially when I'm down, it's really hard to drag myself out of bed, even though I'm sleeping 2 or 3 times as much as when I feel good.