This might sound a bit naive, but I'll say it anyhow. Some times an event happens that causes me to get The Shakes. When I feel stressed out or anxious I do several minutes of deep breathing to relieve the tension. I know that this might sound silly in view of the extent of some of our PD advancement, but I think that it might be something that works to relieve anxiety in some of us. It works nicely for me:
Lie flat of your back with your hands placed on your stomach. Breath in deeply for seven seconds, hold and release the breath slowly. Do this for five minutes. Do you feel better? Good.