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First, some basics.
The human body is about 60% water. Most of that water (about 2/3) is contained inside the cells, yes, cells are about 70% H2o--necessary for cellular functioning.
That's why proper hydration is related to better skin, teeth/bones, joints, muscles, digestion, weight loss, mental functioning, and on and on.
It is generally agreed that a 2% decrease in body water composition can be detrimental. So, take someone 130lbs...that would be about a loss of 3lbs in water. How does one lose 3lbs in water?
1) Respiration: about 1lb a day, 2) Perspiration (just regular, daily sweating): about 1lb. a day, 3) Elimination: could be 2-3lbs a day (
from Bodybuilding.com).
It's easy to see how on those days when we don't hydrate properly we begin to immediately feel the effects. Imagine if this 130lb person does not have proper hydration
and exercises, he/she could easily be down 4%...can you say, "afternoon headache"?!
In any case, hydrating throughout the day and during exercise bouts is essential to maintain healthy cellular functioning. Common wisdom is to prevent dehydration by drinking enough before exercise, drink about 8 oz. for every 20 min. of exercise, and replace the water you lost (sweat) after exercise. Check this out
8 rules of hydration from Runner's World. Experiment and find amounts and kinds of hydration that work for you. This article also has some helpful
tips to proper hydration.
But wait, not so fast....
We know the adage, if you are thirsty, it's too late, you are already de-hydrated.
However, in 2006 the International Marathon Medical Directors Association suggested "thirst will actually protect athletes from the hazards of both over- and underdrinking," in other words,
drink when thirsty. Uh-oh...
"We live in a water-obsessed culture. Every soccer kid has a water bottle or two. Mothers haul around gallon jugs in their minivans. And every business exec clutches a 20-ouncer while dashing through airports with a laptop and overnighter...But where's the proof? Amazingly, there isn't any. Even in marathons, the available evidence indicates that overhydrating is a bigger health threat than underhydrating"...(
read here). Here, too, be ready to experiment with different amounts and different kinds of drink to find what works for you.
So, as usual in the health/fitness realm, the evidence on hydration is about as clear as Apricot Nectar....mmm, nectar, now that makes me thirsty. Post your suggestions to comments.
(Reminder, this is not presented as advice or expert in any fashion or form. Consult a physician if you have concerns about hydration and your health.)