...because the shape of the water bottle isn't uniform either. Part of my new year's resolution is to drink 4 liters of water per day, so I spend a lot of time looking at those lines. Edit: 4 liters is a lot, but appropriate for my size and activity level. Without conscious consideration I don't drink enough water. It looks blue because the bottle is blue.
Thanks for clarifying, I see what you mean. Could this not be considered a question of drug action then, how it impacts your body? Since all of them will go through your bloodstream, one impacts your hydration levels pre-bladder, one post-bladder - assuming you're correct about the bladder irritation. I'd be interested to find out more about this irritation.
I think caffeine impacts your bloodstream more than this discussion indicates, as it is absorbed into the blood before it can be filtered by the kidneys, transmitted to the bladder, then increasing urination. I assume that increased urination, regardless of pre- or post-bladder, will result in similar effects as alcohol, the difference being the magnitude of the impact (alcohol being the more potent drug, results in more dehydration). Any loss of water should result in higher concentration of solutes, no?
With the information we have, I think we disagree on how to apply the definition of diuretic and how caffeine works, but we're also getting into more complex levels of biology and drug action. I'm sure we could get into very complex chemistry if we wanted haha