Defined by mathmatician, Norbert Werner as a 'method of controlling a system by inserting into it the results of past performance', Biofeedback has been popular for decades. It is a process for mecahnically monitoring bodily functins in order to gain control over them. The process requires a period of training but the results are remarkable and are of vital importance to health. It might sound like magic, but the mind is capable of extraordinary feats. Think for a moment of the Tibetans who, on the coldest of days, could increase their body heat to significant levels. Heart rate, blood pressure, breathing, relaxation, brain rhythms, are just for starters. I have heard of excellent results for excema, migraine, gastritis and other very common ailments.
Some useful pages here for those who want to learn more: http://onlinelibrary.wiley.com/book/10.1002/9781118485309