A long time ago, I remember someone, somewhere, tickling someone while hooked up to a Bio-Feedback system/machine and a pulse monitor as well as having their blood pressure monitored.
This was way back before the internet was even someones dream.
I think the article was in Readers Digest? (a guesstimate)
I forget the specific results, however all bodily systems increased significantly(no surprise there) and of a "positive" nature.
I would like to see(and take part in) further experinments that involve all of the above mentioned, including the EKG, respirations,brain function including the release of Endorphins therein as well as Psychological changes and alterations of the test subjects.
Tickling could end up as a complete Cardio/Psycho/Physciolgical theraputic work out.
TTD