THANK YOU FOR VISITING SWEATSCIENCE.COM!
As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.
- Alex Hutchinson (@sweatscience)
I can’t resist posting this follow-up to last month’s discussion of a paper proposing that one of the reasons we’re getting fatter is that we heat our houses too much. Where’s the evidence, you demanded? Ask and you shall receive…
Peter Janiszewski over at Obesity Panacea recently had an interesting post describing a prospective study that followed 1,597 people for six years, looking for “relatively unexplored” factors that might predict who becomes obese and who doesn’t. One of the factors they looked at was the temperature people kept their homes at:
[A] twofold increased risk for both incident obesity and hyperglycemia was estimated in subjects living at an indoor temperature >20 C.
While there are all sorts of cause-and-effect questions to worry about, I should point out that the 315 people who were obese at the start of study weren’t included in the analysis of what caused obesity; similarly, the 618 people who started with hyperglycemia were excluded from the analysis of what caused hyperglycemia. So it wasn’t just that people who are already obese prefer warmer temperatures (which would be the opposite of what I’d naively expect anyway).
Of course, I should include the disclaimer from the paper:
It might be hypothesized that metabolic processes are favorably affected by an ambient temperature within the thermal neutral zone, that is, not requiring energy expenditure to be allocated to maintaining a constant body temperature. However, no evidence exists to support this and socioeconomic factors might confound these associations.
As Peter noted (rather forcefully!) in his blog post, this idea is way out there on the fringe. And no one, including me, is suggesting that it’s a dominant factor in causing obesity. But perhaps it’s actually worth considering as one of the elements in an “obesogenic environment.”