Why does reading, especially reading poetry, calm me down? it works better than exercise for me.

It probably: triggers certain centers in your brain that promote rest and relaxation

Roses are red: Violets are blue, thats a very good question, I am going to answer for you. WHen you concentrate on your reading everything else, all your worries are forgotten about. its your solitude.

To each his own.: Reading opens the imagination, and helps the reader to escape their life, even if only temporarily. For you, poetry obviously is your escape, your happy place, your source of solace. That's great. It's great to have something like that to escape to when you need it.