I pretty much agree, generally with
Carbonfiberboy . As for the
Do not: drink more than 1 liter per hour, 1.2 liters is the limit, that's 40 fluid ounces.
if this is pure water with no added electrolytes either in the water or from tablets or food, then yes that is a point to start worrying. As for water consumption when augmented with electrolytes ...... I think that much less dangerous, but still maybe some risk.
I've ridden in 100°F plus temps and I don't think I came close to that much water in one hour. On my ride yesterday, I did consume 56 oz. in 1:53 hr:min on a 30 mile ride. It was only a tad over 95°F and being late afternoon the dew point and humidity tolerable.
Still not sure on the contention of urinating every three hours. I'd swear I've done five hour or more and never felt the need. But maybe I'm mistaken. It's been a while since I've ridden three of more hours so maybe I used the restroom or road side somewhere and don't remember. But as far as ever being dehydrated and having dark urine? I haven't had dark urine in years. Even when I wake up after six to eight hours of sleep I don't have dark urine. And I don't think I sleepwalk and pee in my sleep. <grin>