I have been drinking 1 gallon of water a day for a few years and definitely notice when I don't get as much water. lately I have increased the intensity of my workouts and diet, and have been getting cramps during workouts. My coach said I need to increase my water intake because cramps are a sign that my body is using salts to eliminate waste, and if I consume more water it will take less salt for my kidneys to eliminate waste, thus easing the burden on them.
So the past couple weeks I have been drinking 1.5 to 2 gallons per day and I am still finding I get thirsty sometimes! LOL. Kinda crazy, but definitely working for me because my cramps have subsided.
Unfortunately there isnt much "fact" on why we get EAMC (exercise associated muscle cramps). It used to be the general consensus that muscles would cramp during exercise due to dehydration and electrolyte loss. Obviously we DO know that when you sweat, you secrete water and electrolytes (sodium, potassium, magnesium etc) which are the same electrolytes that help control muscle nerve impulses that allow your muscles to contract, so that only makes sense as to why a muscle would cramp.
Unfortunately through many study findings we know that when your body loses water in the form of sweat your electrolyte levels in the blood generally rise not fall. They've also found that through controlled electrical induced muscle cramping tests that athletes who were dehydrated were no more likely to sustain cramping than someone who was fully hydrated. There have also been dozens of studies that show drinking electrolyte heavy sports drinks (gatorade/powerade) do nothing to prevent EAMC.
We do know that imbalanced and/or low electrolyte levels DO in fact cause muscle cramping, but someone with a true electrolyte deficiency will have full body systematic cramping, while most if not all of EAMC effect only the muscles that are fatigued. It is also a fact that someone who is severely dehydrated can experience muscle weakness and cramping due to the fact that water makes up most of your muscle cells, but with that said, it would effect much more than the muscle that was fatigued and or overused during intense exercise as that muscle/muscle group would pull water/electrolytes from its surrounding muscles causing a wide spread cramping episode.
The biggest study and most well known that contributed to the electrolyte imbalance theory was the pickle juice study where they found an athlete who was having EMAC's could almost instantly stop and prevent further cramping by drinking pickle juice. Years later through other research it was found that the cramping stopped before the speed in which the sodium and other electrolytes could actually be absorbed. They found it was just the salty taste tricking the brain to relax the muscle. The true reasoning behind this is still unknown, but it DOES work quite well and almost instantly. I know I personally keep salt packets in my competition bag to throw down if I begin cramping.
I am by no means saying that you shouldn't be hydrated or that you shouldn't drink more than a gallon of water a day. I am a big proprietor of drinking a lot of water throughout the day, especially for athletes and those who don't train naturally. I just wanted to geek out for a second and explain that the real cause of muscle cramps during exercise is still very much "theory". They are now starting to lean more towards just simply "fatigue" causing your muscles to experience EAMC's through neuromusclar misfires to a tired, overused and over fatigued muscle.
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