Great post. I've noticed that a bit of exercise outside tends to reduce my stress levels quite a lot. A run, or even better if I can swing it, a bike ride. I'm not sure if it's the change of environment, the endorphins, or the vitamin D. Maybe they all work together.

For a while I was practicing daily meditation. The effects are more subtly noticed, but upon reflection, I think it also helped with stress (among other benefits.)