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SALO employees, from left, Keasha Johns, Katie Kalkman, Nicole Christianson and Loralee Wick walked as they worked.

DAVID JOLES • djoles@startribune.com,

Sitting all day at work can be dangerous for your health

  • Article by: Richard A. Lovett
  • New Scientist
  • July 28, 2013 - 7:04 PM

Ruschy is the chief talent officer at the downtown Minneapolis office of Salo, a financial consulting and staffing agency. Ever since being recruited to take part in a Mayo Clinic project in “inactivity research” — which suggests that sitting at a desk all day can be bad for your health, even if you regularly exercise — Salo has embraced what the company calls “a culture of movement.”

The 55-person office has 11 treadmill desks that workers can sign up to use in four-hour blocks. They also can adjust their regular desks so they can stand for part — or all — of the day. The office is set up with large open areas to encourage the staff to move around, a task made easier by remote telephone headsets like the one Ruschy uses. And they encourage what they call “walking meetings.” Yes, there’s a conference room, but it’s also equipped with treadmills.

“People ask me all the time: How can you walk and type at the same time?” Ruschy said. “The treadmills only go 2 miles per hour,” which is about half the typical walking pace. “It’s not like we go home at the end of the day all sweaty.”

The Mayo study, which is what introduced the treadmills into the office, was focused entirely on health. And the Salo employees got healthier, with their cholesterol counts and weight both going down. (They averaged an 8.8-pound weight loss.) But the reason the firm decided to keep the treadmills was that several other things went up, including productivity and profits.

“Our bodies were not meant to sit as much as we sit,” Ruschy said. With movement incorporated into the workday, “we maintain our focus better, we have a higher energy level and we’re more productive.”

Dr. Michael Jensen, a researcher at the Mayo Clinic, was studying weight control when his team discovered that some people “spontaneously start moving around and don’t gain weight” when they have overeaten. These people don’t dash to the gym; they just walk more, hop up from the couch to run errands or find other excuses to get onto their feet.

“This really got us thinking about this urge to move,” Jensen said, “and how important that might be for maintaining good health.”

Saying that sitting all day can be bad for your health might sound like a statement of the obvious, but the killer point is this: Inactivity is bad for you even if you exercise. Heading to the gym is not a license to spend the rest of the day on your backside. A study by Alpa Patel of the American Cancer Society found that people who spent hours sitting had a higher mortality rate even if they worked out for 45 to 60 minutes a day. The researchers call these people “active couch potatoes.”

A ‘sobering reality’

David Dunstan, a researcher at the Baker IDI Heart and Diabetes Institute in Melbourne, argues that excessive sitting “should now be considered an important stand-alone component of the physical activity and health equation.

“The sobering reality is that across a 14- or 15-hour waking day, we’re getting 55 to 75 percent sedentary time,” he said. “Moderate to vigorous activity — what people call ‘exercise’ — occupies just 5 percent or less of people’s days.”

That’s not the lifestyle to which the human body is adapted. “From an evolutionary point of view, we are built to be active,” said Audrey Bergouignan, a human physiologist at the University of Colorado at Denver. “Your grandparents were not going to the fitness center. They were active all day.”

Bergouignan’s research has been concerned primarily with the effects of prolonged inactivity on astronauts, but the results also apply to earthbound subjects.

The studies revealed that inactivity produces a complex cascade of metabolic changes. Unused muscles not only atrophy but also shift from endurance-type muscle fibers that can burn fat to fast-twitch fibers that rely more on glucose. Inactive muscles lose mitochondria, the cells’ power packs, which also can burn fat. With the muscles relying more on carbohydrates, unburned lipids accumulate.

“Your blood is going to become very fatty,” Bergouignan said, which could be why sitting has been linked to heart disease.

Other changes involve insulin resistance, a diabetes-like condition in which glucose accumulates in the bloodstream. All of this happened very quickly in the astronaut studies. “In three days we have insulin resistance,” Bergouignan said.

Keep moving to keep healthy

So what can we do to avoid this, other than quitting our desk jobs and taking up nursing, hairdressing, waiting tables or other jobs that require us to be on our feet?

First, it’s important to note that exercise still has great merit. Because of its slow speed, a treadmill desk doesn’t provide any of the aerobic benefits of a workout. Patel’s “active couch potatoes” fared better than people who did not go to the gym.

That’s a message exercise advocates don’t want to get lost. “We know that if you exercise 40 to 60 minutes a day, you’re going to have a health benefit,” said Inigo San Millan, director of the Human Performance Laboratory at the University of Colorado Hospital’s Sports Medicine Clinic in Denver.

The researchers also have found that short activity breaks — as little as moving around the room a few minutes an hour — offsets much of the damage done by sitting. And whatever productivity is lost by being away from your desk is made up by increased efficiency once you return.

“People who get up and move around for five minutes every hour are every bit as productive as people who sit there for hours at a time,” Jensen said.

The same advice applies at home. If you’re surfing the net on the computer, Dunstan suggests, “take a break and do the dishes.” If you’re watching TV, get up and move around every 20 minutes.

Patel adds that this is good news for the millions of people who have not been able to get close to the recommended daily exercise levels. “The nice take-home message,” she said, “is that anything is better than nothing. Just getting up and moving at all is taking a big step in the right direction.”

 

Staff Writer Jeff Strickler contributed to this article.

 

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