If you have ever endured one of those tiresome mini-sermons from a well-meaning friend in which you are exhorted to drink 8 glasses of water a day because some study (which, interestingly, he can never actually cite) has shown that this is essential to the human body, you will appreciate the fact that is not actually true.
And you may also enjoy the debunking of other "hydration" myths, such as that caffeinated drinks don't provide you with sufficient "hydration."
In fact, if your personal health advisor (who you never actually invited to serve in that role) uses the term "hydration" in his everyday speech, you should immediately flee his presence and avoid him in the future. This is a sure sign that he is familiar with the language of the Health Nazis, who, if you take their medical advice, will have you wearing one of those pretentious water bottle collars and overdosing on dietary supplements.
If this friend is important to you, just send him an occasional greeting card to maintain the relationship.
Note that I have placed the word "hydration" in quotation marks. I have a policy here at this blog that there are certain words that should always appear in double quotes to emphasize their ideological character and their propensity to hypnotize you into unconsciously assenting to any statement in which they are included. "Hydration" is one of these words.
There are even whole complex expressions that must be set off in this way, such as "scientific studies have shown..." In fact, even the post I have here linked to, which says that 8 glasses of water a day are not required to sustain adequate human life is itself subject to this caution. It too is based on some other, more recent study, equally questionable. Next year "scientific studies may show" that we need 25 glasses of water a day for our bodies to operate properly.
Just make sure your plumbing is sound and that you're not planning on taking any long car trips.
We've experienced this same phenomenon of shifting recommendations with admonitions about coffee, eggs, and which way to turn the baby when he sleeps. You wouldn't think it would be this way.
I mean, what with science being so certain and all.