The spO2 business still sounce like baloney to me but WTF do I know. If someone can produce an actual study linking blood O2 saturation to training fatigue (or whatever it allegedly tells you) in a consistent way, I might buy it. Till then, I'll continue to assume it's pseudoscience.
Edit: the basic search I've just done is not reducing my skepticism.
Last edited by grolby; 12-14-15 at 09:06 PM.