Originally Posted by Dewbert
A knowledgable friend of mine tells me that you're properly hydrated when your urine runs clear (or nearly so).
Anybody else know if this is accurate or reasonable?
Not necessarily because it can also result from other physiological symptoms as well. The rates of deaths from hyponatremia has been on the rise. It's partly from inadequate intake of electrolytes and partly from excessive water consumption. These victims have had clear urine before their deaths; they're overly hydrated. A lot of people see nutrition in clear-cut, yes/no, black&white, all-or-nothing terms of extremes (no fats, no sugars, no salts, etc.). They also go to the other extremes with "drinking water is good, so A LOT of it's even better"
. So they sit around watching TV and drinking water. They'll bring bottles with them everywhere and sip on water constantly.
The problem with this is that not much excess water is stored, it's excreted out as urine. Due to the ion-gradients in the kidneys (salt-column), you cannot just pee pure-water, minerals and salts are always flushed out as well. Mineral-deficiencies are a very common ailment with those who drink only distilled water. So.. in the process of getting to the "pure" clear urine, you end up having to drink 2-3x as much water as necessary for completely re-hydration. You've dumped a whole bunch of salts and minerals out of your body as a result.
Combined with the mistaken "no-salt" nutrition, you become severely depleted in electrolytes. Many don't realize that electrolytes must be replenished based upon activity, just like water. An active athlete will actually require 200-600% more sodium and other electrolytes daily compared to sedentary couch-potatoes. Common symptoms of low electrolytes show up as muscle-cramps and light-headedness when standing up quickly. So.. there's no simple "always" answer. Water should be consumed on an as-needed basis to replace the amounts that have been sweated away.
Additinally, you also have to balance water vs. nutrient absorption in digestion as well. Pure water absorbs the fastest, however you also need to take in nutrients. Too high a concentration of solids or carb-complexes will slow down water-absorption. The RAAM folks sacrified water-intake for nutrient intake since they needed as many calories as possible per hour; the riders always ended the day slightly dehydrated as a result. Most people can usually settle on around a 200-cal/hr intake of nutrients with electrolytes. Then about 500-750 ml/hr of water depending upon activity intensity and ambient temperatures. A better way to judging adequate hydration level is to weigh yourself before the workout. Then weigh yourself afterwards and make sure take in enough water to weigh roughly the same (minus weight of recovery foods).
Last edited by DannoXYZ; 01-03-06 at 05:56 AM.