First off all: I am sorry for not being here over a couple of years. Through my troubled life I simply missed out on it. I would like to post the results of two basic blood tests, that have been done a long time ago and that I stumbled over just recently: PH 7,38 / 7,37 (7,35 - 7,43) pCO2: 46,2 / 43,4 (37 - 50) pO2: 61 / 58 (36 - 44) Now, this is NOT an aterial blood gas analysis (like it is used to monitor emergency cases), but a venuous test. So it tells a different story. The first ones are meant to monitor vital functions. You probably have heard falling oxigen pressure as sign of emergency, featured in most medical drama series. Venuous gases may not tell so much in the classical context, but probably a lot more with regard to CFS. What does it mean, when your muscles are burning? It does not make any difference wether it is someone suffering from CFS or an athlete going beyond his aerobic threshold. The muscle is simply lacking oxigene. The "burning" is caused by lactate acid due to anaerobic burning of carbohydrates. So if muscles are burning from low level excercise, there must be something wrong with oxigene supply. If we assume, that this is not being caused by cardiopulmonary complication, there must be something wrong beyond. Even though there is enough oxigene, muscles seem to be unable to saturate their specific requirement. And that may even be true in an idle state. So what if your body tissue rejects much of the oxigen provided? Yes, it will be transported back to the loungs, and in the venuous blood, you will have highly elevated pO2 levels. At this point we are comming back to the above test result. If you have CFS, that should be visible in a venuous gas test.