Hello, I have an HHV-6 IGg of 1:1280 but the doctor said it was an inactive virus. But I convinced him to give me Valcyte because I have EXTREME, brain fog, fatigue and some anxiety. I was also wondering about one other thing that maybe someone could help me with. I am 39yo and use to be a competitive 5k&10K running usually running about 5:50 minute miles. Well when these other symptoms I mentioned reared their head about 5 years ago I also noticed I became out of breath A LOT quicker and could not run the same. I have had just about EVERY test known from all different doctors and the only thing that has every come up abnormal is the HHV-6 IGg levels. My doctor is very convinced the virus is inactive so I don't know what to say about that. Has it been shown that an active HHV-6 virus can compromise VO2 max levels? Thanks very much. Oh, btw I have had the Valcyte for 7 months now and have not taken it......scared of the side effects and potential permanent one but I think I am going to be forced to try it.