Something I've started doing that's had a very marked impact on my sleep is going for a walk each morning. I've always been very active at night (with terrible

Something I've started doing that's had a very marked impact on my sleep is going for a walk each morning. I've always been very active at night (with terrible trouble falling asleep), and always been a zombie in the morning; but this seems to have shifted my wake cycle in such a way that I'm alert and productive during the day and tired at night instead. Hell of a thing.