Mythbusting

[trixtah]

I've come across that old chestnut that averagely-active people "MUST drink 8 glasses of water a day" four times in the last week, in various formats. And I wish that people would stop spreading that idiocy around. Yes, we do need to consume about that much fluid in a day, but, surprise, surprise, we get at least half of it in our food. The component of that myth that I find particularly galling is that "when you're thirsty, you're already dehydrated". What crap. Thirst is how your body stops you from being dehydrated.

A well-publicised review was carried out a few years ago by Dr Heinz Valtin, who pretty much debunked all those myths after examining extant literature and studies. Here's the part about the "thirsty is too late" myth:

...a rise in plasma osmolality of less than 2% can elicit thirst, whereas most experts would define dehydration as beginning when a person has lost 3% or more of body weight, which translates into a rise in plasma osmolality of at least 5%.

Oh, and as for the rubbish that caffeinated drinks don't count for fluid intake because they act as diuretics? Well, they're not diuretic enough to totally purge you of all that liquid you just consumed, thus upping your total fluid intake. Alcohol, however, will dehydrate you. And if anyone has experienced a hangover, you know how different that feels compared to being a bit thirsty.

Snopes has a good rebuttal of that stupid "75% of Americans are chronically dehydrated" email that appears to be doing the rounds again. But the Valtin study is very readable as well, and good for more background.

Really, like anything else, it all comes down to listening to what your body is telling you. If you are thirsty, drink. Simple.

Comments

[filkferengi]

Thanks for posting this. Listening to our bodies *is* important. Last year at GaFilk I cut back on the drinking, so I wouldn't have to cut out during the concerts. I wound up with a fever of 101 Saturday night & had to blow off Sunday [to be rested up for busing visiting Brits all over the metro area for 4 very full days]. This year I drank more, avoided sitting under the air conditioner, & went home earlier Saturday night. I hated missing out on fun at the con, but was more rested, didn't get sick, & was able to hang around some of Sunday. [Busing the Brits only 2 1/2 days helped, as did getting home earlier at night & getting more rest. Entertaining company's one thing, but there's no need to kill myself doing it, especially now I've shown them where the attraction flyers & transit maps are. :)]

[trixtah.livejournal.com]

Oogh, that sounds nasty. I utterly refuse to sit directly under air-con - it's amazing how much moisture those things suck out of your body.

I'm with you on the wanting to escort visitors around - I want them to feel taken care of, and to give them the best view of my town as possible. However, we all have limits, mental and emotional as well as physical!