Originally Posted by
kidchill
There's just too much disinformation in this thread and it's gonna lead to fear mongering. Tanking up, or as I call it "cameling" isn't about taking in "extra" water. You're not stopping and drinking a gallon at a time. I hit a water source, slam a liter and keep moving. Why? Because water is heavy and I hate carrying it! This doesn't mean I'm consuming "extra" water, it just means I'm not sipping as I go...I replenish and move on. Hyponatremia by definition is too little sodium per unit of volume in the extracellular space. Ions are usually measured by mEq/L and the normal serum Na concentration is 135-145. Dip below this range and you're looking at lethargy, confusion, loss of consciousness, coma, seizures, and cardiovascular collapse. In short, it's not good. Low sodium is usually the result of dilutional factors. This is why you hear the term "water intoxication." There's two main fluid compartments within the body, intracellular and extracellular. Intracellular is within the cells, extra is outside of the cells. The extracellular volume is also comprised of compartments, interstitial (between the cells) and intravascular (within vessels...this is your blood). There's also potential spacing but that's not really important here. Ions are also divided up into intra and extracellular. Wherever the ion is most concentrated is where it's considered to be. Sodium is an extracellular ion( sorry but sodium is only mainly extracellular but we have sodium intracellular also which the balance is regulated by exchanging potassium with sodium, potassuim is more intracellular sodium more extracellular but we still have intracellular sodium and extracellular potassium) and correlates directly with chloride ions. NaCl is salt. What's happening with water intoxication related to hiking is people are out in the heat, working themselves, and sweating. Sweat isn't just water, it contains salts. You're essentially oozing salts and fluids out of your body, and then replenishing just the fluids. This dilutes the extracellular Na and leads to conduction abnormalities in the central nervous system...Hence all of the bad things happening with your brain. Unless you have dysfunctional kidneys, some kind of hypoaldosterone pathology, or you consume an insane amount of fluids rapidly, your kidneys aren't gonna spray out Na all willy-nilly. The excessive sodium loss is via sweating. If you and I are both using the same amount of water per unit time, and I camel a liter for the next hour, and you sip your liter for the next hour, it's essentially the same thing. It's still the same volume per unit time. I think you're assuming that "cameling" is drinking an insane amount of fluid in a short amount of time and your body just spills it out. That's not how it works.
"In a normal individual any extra water turns to urine in less than 30 minutes and does not make any real difference in hydration status of the individual." I have no idea where this came from( Forget about it that I have been a medical doctor for 20 years and passed the qualification exam in UK just six years ago this comes from the fact that when you drink excessive water you feel the urge to urinate in half an hour, Plain and simple ). If I slam a liter of saline in a patient in 15min, they don't pee out a liter within the next 30minutes. IV fluids are going directly to the intravascular compartment, filtered directly through the kidneys...I think you'd be hard pressed to find data that supports that statement.
I'm not down playing the risk of water intoxication...I just want to make it clear that slamming a liter ever so often, versus sipping a liter in the same time isn't going to lead to acute water intoxication. Is it probably "nicer" for the body to sip fluids over time, yah, probably( not probably, definitely), but are you placing yourself at extreme risk by doing so? Probably not. Most of the stories I've heard about water intoxication or extreme dehydration were totally avoidable. You really do have to work at it to jack up your electrolytes. Also, everyone focuses on how thirsty they feel, no one ever talks about their urine. Urine should be clear yellow...not yellow, not dark yellow, definitely NOT tea colored...clear yellow! If your pee is getting dark, drink more fluids.