Answer: Endorphins
Explanation: Endorphins are chemicals secreted by the brain also known as neurotransmitters that send electrical signals inside the nervous systems.
The factors that initiate the secretion of endorphins are stress and pain.
When endorphins are secreted they reduce feelings of pains, and in runners that cause a phenomenon called " Runners high" which allows runners to keep running without feeling pain or stress.
Uuuuhhhh....I'm gonna assume its clinical and nonclinical.
