You do realise that the article you have linked to is on the Cardiovascular Diabetology " is a peer-reviewed open access medical journal covering the intersection of cardiology and diabetology, meaning the connection between diabetes, metabolic syndrome and cardiovascular diseases."
They are talking about GV in diabetics (which is caused by timing of man made insulin against the natural digestion of food (and glycogen from the body)), if a none diabetic is having 400mg blood sugars, they are in serious trouble and will not be worried about sporting performance,
As a T1 (which I have said several times above) diabetic GV is of great importance to me, so please don’t talk down to me about this