Non-interventional study design. Hydration measured by osmolality. I wonder if other factors like glucose level could affect both osmolality and cognition? Wo

Non-interventional study design. Hydration measured by osmolality. I wonder if other factors like glucose level could affect both osmolality and cognition? Would be much more interesting as a randomized trial (though I'm not sure what would make a good placebo intervention as a control).