With Arizona temperatures firmly settled into triple digits for the foreseeable future, it's natural for us to think about dehydration. Heck, it's critical. And - for me - today's trip to the bank really brought that home.
Naturally, since our bodies are about two-thirds water, we need to make sure that we replace fluids that are lost in a normal day. But does that truly mean guzzling 6 to 8 glasses of water a day? Truthfully, I would have to say that depends.
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I must admit, I loved the article from snopes.com. No one knows where the eight-glasses-a-day rule came from, and there are most certainly experts on both sides of the issue, pointing fingers and crying foul. But I was looking for information about how much fluid we lose on a daily basis. This quote, I think covers it:
To replace daily losses of water, an average-sized adult with healthy kidneys sitting in a temperate climate needs no more than one liter of fluid, according to Jurgen Schnermann, a kidney physiologist at the National Institutes of Health.
Food
Not all of the fluids that we take in during an average day come from beverages. Depending on our diet, we could be adding two or three of those 8 oz. glasses through fruits and vegetables, alone.
Foods with high fluid content include:
- 1 medium Apple - 4 oz.
- ½ medium Cucumber - 5 oz.
- ½ medium Grapefruit - 4 oz.
- 1 small Potato, baked 5 oz.
- 1 small Potato, boiled 6 ⅓ oz.
- ¾ cup Soup, average - 5 ⅓ oz.
- 1 small Tomato - 4 oz.
- ½ cup Watermelon - 2 ½ oz.
It's easy to see, with just these few items, how simple it is - especially right now when produce is at its best - to keep hydrated. All without guzzling copious amounts of water.
Bad Beverages
Not all fluids are created equal.
Caffeine
For years, we have been told that drinking coffee and tea leads to dehydration. This is apparently based on the fact that coffee and tea contain caffeine, and caffeine has a diuretic effect on the body. However, a 2003 review of medical and scientific literature for the period of January 1966–March 2002 found that, in simple terms, if you indulge in caffeine on a regular basis, you are likely to be immune to the mildly diuretic effects.
If you rarely drink tea or coffee, when you do indulge, you may spend more time in the bathroom than your neighbor - the caffeine junkie. But there is no evidence, according to this review, that simply having a cup or two of coffee will cause you to pee out more than you drank. You probably don't need to drink extra water to counteract the caffeine.
Alcohol
Like caffeine, alcohol has a diuretic effect on the body. However, it's just a little more aggressive. (If you've ever had two beers and peed out four, you know what I mean.)
To paraphrase this article on kidney function: to conserve water, the pituitary gland excretes vasopressin (also called anti-diuretic hormone or ADH) which, in turn, increases permeability of the nephrons in the kidneys. More water is kept in the bloodstream; less is released in urine. Alcohol causes dehydration by blocking release of ADH, removing fluid from the system and sending it to the bladder.
If you regularly consume large amounts of alcohol, you are regularly at risk for dehydration. You may very well need those 6 to 8 glasses of water per day, just to keep up. That glass of wine with dinner? Probably not an issue.
Fluid Loss
Perspiration
People who live in the desert or exercise regularly, know that excessive sweating leads to excessive fluid loss. By the time you're thirsty, according to common wisdom, you are already 2% dehydrated. So, for us desert dwellers and you exercisers, 6 to 8 glasses of some sort of fluid every day is already the norm.
If not, it probably should be.
Illness
Vomiting, diarrhea, and/or a sweaty fever are other ways we suffer fluid loss. In the midst of a nasty bout of the flu or a wicked virus, it's not always easy to get enough fluids. Your stomach may simply reject everything you try to swallow.
Even if it's only a few sips of water, followed by a few more, fluids are critical when you're sick.
Conclusion
What I have tried to do is look at fluid intake and common causes of dehydration - whether they hold water (pardon the pun) or not. I'm no medical expert, but it seems to me that, when clean drinking water is readily available, hydration is reasonably simple. And, despite the hue and cry from some quarters, I believe that few of us are at risk of imminent death from dehydration.
I don't suppose that taking in 48 to 64 ounces (6 to 8 8-oz glasses) of fluids over the course of the day is going to hurt anyone. I just don't see it as some do-it-or-you'll-die mandate. Especially when there's really no scientific basis for it.
What do you think? Good or bad? Sane or silly?