As the axiom goes, rehydrate or die!
Water is fundamental to sustained energy output, try downing that carbo powder by the spoonful at altitude

, cough, cough i hear you say.
Not long after i started hiking, it would have been about 1993, I decided I had had enough of small water bottles and jury rigged up a rehydration pack out of a plastic bottle and fish tank tubing. The bottle had "Kiddies Corner" emblazoned across it, for all to see however stupid it looked, it did the trick. I had two holes in the top, one for the tube, and the other for a second small tube, cable tied to the main tube to prevent a vacuum forming and preventing any fluid from being delivered. There was no bite valve, so you had to blow back on the fluid to prevent it from siphoning the contents over your leg.

Backwash yeech!
The point was that it worked, and i cld fill it with about 2l of water, and thus did not have to keep filling the small bottle, or stop walking to rehydrate, however with the tube near your mouth, you never had to go thirsty.
Eventually in the naughties, bite valves, and a plethora of hiking gear arrived in the country, and with a kayaking bladder and a v. small day pack strapped to my pack, I had a very cheap "Camelback", which were ridiculously expensive then, and still are today.
Other uses, include using the pipe as a tornique, or to garrote your snoring hiking partner, although throwing something at him works just as well, also perhaps as a miniature shower head. Using the tube without the bite valve to create a siphon from very small pools of water, when not much is available and you can barely even get a teaspoon submerged. On a trip along the Bell's Traverse, I used this method when the only water was a trickle into a small saucer sized depression in the ground, and was able to fill up our bags and bottles for the next days section.
So which is it, water bottle or rehydration pack