Progressive muscle relaxation is an integral part of biofeedback training, but can be used by itself for the treatment of migraine and tension-type headaches.   A group of researchers at the Ohio State University published an article in the journal Pain which reports the effect of progressive muscle relaxation on experimental pain in healthy volunteers.   A single 25-minute tape-recorded session of progressive muscle relaxation resulted in a higher pain tolerance and reduced stress from pain.  It can be safely assumed that regular practice sessions will result in even better results and all pain patients, including those with headaches should be encouraged to learn this simple technique.