This may be of interest to you.
And some references on the effects of dehydration and CGM accuracy. I don’t rely on CGM during exercise. I sometimes bring it along for general illustration purposes, but I go with BG tests for my actual numbers now.
However, it might be that longer-duration exercise and the potential for dehydration could decrease the glucose supply within the interstitium, resulting in lower glucose levels compared to the capillary and venous systems. Furthermore, the lag time in interstitium could be influenced by the intensity of exercise and the amount of circulating insulin. Low insulin reductions combined with high exercise intensities could increase the lag time between the blood and the interstitium, resulting in severe impairments for continuous and flash glucose monitoring systems.