美国上班族流行站着工作

Mark Ramirez, a senior executive at AOL, could work in the cushiest leather chair, if he wanted. No, thanks. He prefers to stand most of the day at a desk raised above stomach level.

"I've got my knees bent, I feel totally alive," he said. "It feels more natural to stand."

In the past few years, standing has become the new sitting for 10 percent of AOL employees at the firm's Virginia campus, part of a standing ovation among accountants, programmers, telemarketers and other office workers across the nation.

GeekDesk, a California firm that sells $800 desks raised by electric motors, says sales will triple this year.

Standers give various reasons for taking to their feet: It makes them feel more focused, prevents drowsiness, makes them feel like a general even if they just push paper. (Former defense secretary Donald Rumsfeld works standing up. So does novelist Philip Roth.)

But unknown to them, a debate is percolating among ergonomics experts and public-health researchers about whether all office workers should be encouraged to stand — to save lives.

Doctors point to surprising new research showing higher rates of diabetes, obesity, heart disease and even mortality among people who sit for long stretches. A study earlier this year in the American Journal of Epidemiology showed that among 123,000 adults followed over 14 years, those who sat more than six hours a day were at least 18 percent more likely to die during the time period studied than those who sat less than three hours a day.

"Every rock we turn over when it comes to sitting is stunning," said Marc Hamilton, a leading researcher on inactivity physiology at the Pennington Biomedical Research Center in Louisiana. "Sitting is hazardous. It's dangerous. We are on the cusp of a major revolution." He calls sitting "the new smoking."

Not so fast, other experts say. Standing too much at work will cause more long-term back injuries. Incidences of varicose veins among women will increase. The heart will have to pump more.

Hedge, the Cornell professor, isn't a fan of all this standing. "Making people stand all day is dumb," he said.

The sensible and most cost-effective strategy, he said, is to sit in a neutral posture, slightly reclined, with the keyboard on a tray above the lap. This position promotes positive blood flow. Workers should occasionally walk around, stretch and avoid prolonged periods at the desk. The key, he said, is movement, not standing.