The wim hof method has worked well to reduce my tinnitus and headaches in the short term, and I'm guessing it has had good effects in the long term. I did it regularly while I was suffering badly in the months following my concussion, and do it sporadically now, when I have "background" tinnitus that I pretty much ignore. It has always seemed to reduce the "volume" of the tinnitus and/or headache.