Sitting Kills: For Your Heart, There Is No Faking Fitness

In March, my life tally included a wife, a three-year old, and a condo. In two months, we sold our condo, moved into a rental place, had another kid, bought a house and moved in. During this time, I spent nearly 8 hours a day sitting at work, another few hours sitting at home (or packing boxes and lifting furniture), and the rest lying my back (sleeping). My exercise, other than walks to the park and wrangling kids, was running 3 miles or so every other day. I've been thin since birth, and my weight hasn't changed since 7th grade, so I consider myself reasonably healthy, even if I don't have the time I'd like to get more regular exercise.

So the article "The Men Who Stare at Screens" on NYTimes.com was disheartening and a little scary. To your heart, it doesn't really matter how much exercise you get if you spend most of your time on your butt.

"Men who spent more than 23 hours a week watching TV and sitting in their cars (as passengers or as drivers) had a 64 percent greater chance of dying from heart disease than those who sat for 11 hours a week or less. What was unexpected was that many of the men who sat long hours and developed heart problems also exercised...Their workouts did not counteract the ill effects of sitting...Your muscles, unused for hours at a time, change in subtle fashion, and as a result, your risk for heart disease, diabetes and other diseases can rise."

If this seems alarming, you should read the rest of the article. Basically, the modern workplace forces the white-collared to sit all day. Modern home life allows us the free time to be entertained via screen. We've replaced the daily light-intensity activities of our grandparents with screen time. We've become "active couch potatoes."

The study in the article relies on a measure called metabolic equivalent of task (MET). One MET is the amount of energy you burn lying down for one minute; it ain't much. Two METs would be twice as much energy as you would spend lying on the couch. I've wondered before if METs might be useful as a way to compare apples to apples efforts in different endurance sports.

As is often the case with New York Times fitness coverage, the story merely criticizes, offering no remedy. It would be useful, for example, to suggest MET guidelines on an hourly basis, even if they are a "GuesstiMET" on behalf of one of the researchers. Surely there was some threshold of light exercise apparent in the survey results; people are not merely active or inactive and there must have been some correlation to their health.

Anyway, you can download a list of daily activities and their MET score to help you make your own GuesstiMET of how often to take the stairs.

The Compendium of Physical Activities Tracking Guide (pdf)

UPDATE 1/15/11: The New York Times reports that screen time kills. The Well blog describes mounting evidence that, regardless of your exercise time, too much sedentary "activity" is very bad for your health. This is scary stuff for the white-collar class of professional sitters.