I have read that 80 is a nice normal number for fasting blood sugar but my body doesn't like it at my old age. Obviously things work less efficiently in late age and I am not in prime condition anymore, if I ever was at any time. I was no athlete and thought breaking into a sweat on a Rachmanovich piano piece was great exercise for my body, at least for my fingers and forearms. And I would skip meals to stay at the sewing machine which I had to share with my mother and sister. So we can't compare with today's physical standards.
Those shakes make me think of Parkinson's which is common at our age. I keep studying. Dorisena