Sitting is a lethal activity

DR. LEVINE’S MAGIC UNDERWEAR resembled bicycle shorts, black and skintight, but with sensors mounted on the thighs and wires running to a fanny pack. The look was part Euro tourist, part cyborg. Twice a second, 24 hours a day, the magic underwear’s accelerometers and inclinometers would assess every movement I made, however small, and whether I was lying, walking, standing or sitting.

James Levine, a researcher at the Mayo Clinic in Rochester, Minn., has an intense interest in how much people move and how much they don’t. He is a leader of an emerging field that some call inactivity studies, which has challenged long-held beliefs about human health and obesity. To help me understand some of the key findings, he suggested that I become a mock research trial participant. First my body fat was measured inside a white, futuristic capsule called a Bod Pod. Next, one of Dr. Levine’s colleagues, Shelly McCrady-Spitzer, placed a hooded mask over my head to measure the content of my exhalations and gauge my body’s calorie-burning rate. After that, I donned the magic underwear, then went down the hall to the laboratory’s research kitchen for a breakfast whose calories were measured precisely.

The participants in a series of studies that Dr. Levine did beginning in 2005 were assessed and wired up the way I was; they consumed all of their food in the lab for two months and were told not to exercise. With nary a snack nor workout left to chance, Dr. Levine was able to plumb the mysteries of a closed metabolic universe in which every calorie, consumed as food or expended for energy, could be accounted for.

His initial question which he first posed in a 1999 study was simple: Why do some people who consume the same amount of food as others gain more weight? After assessing how much food each of his subjects needed to maintain their current weight, Dr. Levine then began to ply them with an extra 1,000 calories per day. Sure enough, some of his subjects packed on the pounds, while others gained little to no weight.

“The people who didn’t gain weight were unconsciously moving around more,” Dr. Jensen, a Mayo Clinic researcher says. They hadn’t started exercising more that was prohibited by the study. Their bodies simply responded naturally by making more little movements than they had before the overfeeding began, like taking the stairs, trotting down the hall to the office water cooler, bustling about with chores at home or simply fidgeting. On average, the subjects who gained weight sat two hours more per day than those who hadn’t.

The posture of sitting itself probably isn’t worse than any other type of daytime physical inactivity but for most of us, when we’re awake and not moving, we’re sitting. Electrical activity in the muscles drops, the muscles go as silent as those of a dead horse, leading to a cascade of harmful metabolic effects. Your calorie-burning rate immediately plunges to about one per minute, a third of what it would be if you got up and walked. Insulin effectiveness drops within a single day, and the risk of developing Type 2 diabetes rises. So does the risk of being obese. The enzymes responsible for breaking down lipids and triglycerides for takingg fat out of the bloodstream plunge, which in turn causes the levels of good (HDL) cholesterol to fall.

Sitting, it would seem, is an independent pathology. Being sedentary for nine hours a day at the office is bad for your health whether you go home and watch television afterward or hit the gym. It is bad whether you are morbidly obese or marathon-runner thin.

The good news is that inactivity’s peril can be countered. Working late one night at 3 a.m., Dr. Levine coined a name for the concept of reaping major benefits through thousands of minor movements each day: NEAT, which stands for Non-Exercise Activity Thermogenesis. In the world of NEAT, even the littlest stuff matters.

In a motion-tracking study, Dr. Levine found that obese subjects averaged only 1,500 daily movements and nearly 600 minutes sitting. In my trial with the magic underwear, I came out looking somewhat better 2,234 individual movements and 367 minutes sitting. But I was still nowhere near the farm workers Dr. Levine has studied in Jamaica, who average 5,000 daily movements and only 300 minutes sitting.

Dr. Levine knows that we can’t all be farmers, so instead he is exploring ways for people to redesign their environments so that they encourage more movement.

For all of the hard science against sitting Dr. Levine admits that his campaign against what he calls “the chair-based lifestyle” is not limited to simply a quest for better physical health. His is a war against inertia itself, which he believes sickens more than just our body. “Go into cubeland in a tightly controlled corporate environment and you immediately sense that there is a malaise about being tied behind a computer screen seated all day,” he said. “The soul of the nation is sapped, and now it’s time for the soul of the nation to rise.”

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