Holy ball sweat, it’s hot this year! And that sucks for many, many reasons: Heat doesn’t just make you sweaty and sticky, it doesn’t just make you cranky, it can also make you… dumb.
It’s true — a recent study by Harvard University’s C-CHANGE (Center for Climate, Health and the Global Environment) published in July says so.
The study examined two groups of students during and after a heat wave: One who lived in newer, air-conditioned dorms, and another who lived in older, brick, hot-as-hell-in-the-Boston-summer dorms. The ones who lived, studied, ate and slept in dorms without air conditioning scored 13 percent worse in cognition tests, with 13 percent slower reaction times, than the students who lived in an environment of climate-controlled bliss.
“Normally, heat studies are done on the elderly and the very young because that’s where you see the severe effects,” explains Jose Guillermo Cedeño Laurent, the study’s lead author and associate director of the Healthy Buildings Program at the Harvard T.H. Chan School of Public Health. His group at Harvard, however, is interested in work like this that affects everyone.
“We see in places like Boston that buildings designed to harness heat [in winter] could actually put buildings to the limit of performance — and we identified something we call indoor heat waves,” says Cedeño Laurent. Ever notice how many buildings keep getting hotter even after the sun goes down? This is what he’s talking about — and according to this study, it affects how much sleep you get, which affects your cognition the next day.
While this obviously affects potentially everybody, there are three groups — besides the college-age students in Ceneño-Laurent’s relatively small study — who are particularly at risk. The first of these is school kids from disadvantaged backgrounds (who attend schools without AC), for whom other studies have shown that for every degree of temperature increase, there’s a one percent drop in educational attainment. Then, of course, there are office workers, for whom cognition is generally important, and finally, people who operate machinery, who are obviously among the last people you want going foggy in the head. (It’s an especially disturbing thought every time you see road and construction workers in the summertime.)
It all connects to a growing body of studies that examine heat and human nature. While Ceneño-Laurent was careful to mention the inconclusiveness of his and other studies, he mentioned a recent study in Nature showing higher suicide rates in the U.S. and Mexico during hotter periods, plus other, more controversial bodies of research suggesting a possible correlation — among other factors — between hot weather and increased crime rates. (Although he didn’t mention it, I can’t help thinking that maybe all this helps explain Florida Man.)
In any case, can we assume that Cedeño-Laurent now spends all his time at what his study (which he points out is non-definitive) regards as the optimal temperature (72 to 73 degrees), feeling the gentle caress of air-conditioned breeze on a hot summer day?
Nope: He’s busy thinking of the bigger picture.
“Can’t we do a better job of cooling our environments given that we’ll need it?” he asks. “Eight hundred million AC units will be sold in India and the developing world in the next 10 years, and 1.3 billion units are expected to be sold from now till 2050. The question is, why would we want to put 100-year-old technology in our spaces while this is exacerbating the problem?” He’s right: There’s a positive feedback loop with air conditioners and climate change due to all the energy they burn, and also the refrigerant gasses they contain. “The hydrofluorocarbons produced by air conditioning are up to a thousand times more potent than CO2 as a greenhouse gas,” says Cedeño-Laurent.
Since most people can’t just move into a new home or a new office building on a whim, what are the heat-afflicted supposed to do with our clammy brains? Cedeño Laurent’s study suggests a simple, straightforward protection against cognitive impairment: “Participants that reported having more than six glasses of water per day did better on the test,” he says — whether or not they lived with air conditioning.
So drink up, dummy, and maybe you won’t be so, like, dumb anymore, and stuff.