I’m often struck these days by the sight of young people — primarily women — lugging around absurdly large containers filled with what I can only assume is some form of hydration assistance. At the coffee shop, their vessels aggressively vie for table space among books, laptops, phones, and empty cups of matcha chai latte. It makes me wonder whether they know something I don’t know about the reliability of public water fountains.
This strikes me as odd, I suppose, because I’ve been known to operate for hours during a typical workday without considering the need for a thirst-quenching beverage. It’s a behavioral trait I share with most geezers; we tend not to notice under normal circumstances when we need a drink. I’ll pack some water when I’m traipsing around the golf course on a sweltering August afternoon (there’s only so much beer a guy can drink before his pitching wedge betrays him), but aside from those occasions and particularly sweaty gardening sessions, I generally don’t worry too much about my hydration levels.
That’s why the results of a recent Penn State University study caught my attention. Researchers there reported a tenuous connection between cognitive function and hydration in older adults. Specifically, women who drank too little — or too much — scored poorly on tests measuring motor speed, focus, memory, and other brain functions. Oddly enough, the same results did not apply to men participating in the study.
“As we age, our water reserves decline due to reductions in muscle mass, our kidneys become less effective at retaining water, and hormonal signals that trigger thirst and motivate water intake become blunted,” lead study author Hilary Bethancourt, PhD, explains in a statement. “Therefore, we felt like it was particularly important to look at cognitive performance in relation to hydration status and water intake among older adults, who may be underhydrated on a regular basis.”
Or overhydrated. Senior study author Asher Rosinger, PhD, adds that drinking too much “may be just as detrimental to cognitive performance as dehydration for older adults.” There’s apparently a sweet spot between too much and too few fluids that will keep our aging brains operating at somewhere near capacity.
Bethancourt and her team recruited about 2,500 volunteers 60 years old or older and asked them to report their food and drink consumption from the previous day. Researchers calculated hydration levels based on the amount of sodium, potassium, glucose, and urea nitrogen in volunteers’ blood as well as the water content of their diets before subjecting them to cognitive tests measuring verbal recall, verbal fluency, memory, sustained attention span, and processing speed.
After accounting for education, sleep quality, exercise, and diabetes status, the study found that women were particularly prone to cognitive lapses when under- or overhydrated, while men were unaffected.
Researchers can’t really explain why old male brains seem immune to the effects of hydration, nor are they completely sure whether poor hydration causes cognitive impairment or whether those who are cognitively impaired tend to be poorly hydrated.
My own muddled brain suggests that it’s not just the female cerebellum that suffers from suboptimal fluid intake. And it doesn’t much matter to me whether it’s a cause or a correlation. It probably can’t hurt to pay a little more attention to whatever thirst signals my aging brain sends me. Still, that doesn’t mean I’m going to start lugging around a half-gallon of water everywhere I go. The water fountains are working just fine.
Last time I checked, anyway.