Drink 24 ounces of water 1st thing in the morning and let us know if you feel better.
I measured my daily water consumption and reckon I consume just over 3 litres a day of liquid - that's tea & coffee (both black) wine and water. ( 3L = 101.5 US fl oz)
First thing I have about 200ml fruit juice, then three mugs black tea, roughly 500ml, total 700ml which equals 24 US Fl oz.
Water is water. Tea is flavoured water.
The body has a system for telling you when it needs liquid - thirst. Also you can check by looking at your pee (easier for a man I know) - if its other than pale yellow then you need water. When you fly directly to a very hot climate it is surprising how much liquid your body needs till it re-adjusts, which takes a couple of days. But when the body need liquid it preserves what it has and you suddenly realise you've not needed the bathroom all day. Checking pee colour is, IMO, important in these cases.
I do not believe a large number of Americans or Europeans are dehydrated where we have access to free water on tap. When I have beenin the US it seems almost everyone is sucking on something or carrying a huge paper container of drink. Junk it might be, but its also 99%+ water.
You said earlier
well-hydrated Marathon Runners suffer less complications afterwards. Yes, and some suffer the worst complication of all, death:
Almond et al. Hyponatremia among runners in the Boston Marathon. New England Journal of Medicine. 2005. PubMed #15829535. Comments: According to this report, over-hydrating (hyponatreamia) �has emerged as an important cause of race-related death and life-threatening illness� in marathoners. Race-related death and life-threatening illness! From drinking too much water! The researchers found that hyponatremia does occur in a �substantial fraction� of nonelite runners, and the factors most likely to be associated with it are �considerable weight gain while running, a long racing time, and body mass index extremes.�
I wonder too about the timing of this publicity about 'de-hydration' among well fed Americans with coffee shops on every corner and water glasses in restaurants appearing at the same time as increasing numbers of companies are promoting bottled water products.
Just saying that a blanket encouragement to drink more water no matter what the readers individual circumstances is questionable because it could cause a health hazard.
8 glasses a day is a myth Why is too much water dangerous? - A Cal...nking contest