If "Sitting is Literally Killing" Americans, What Can We Do?

Exercising at the office isn't as hard as you think

On any given day, we sit a lot: at breakfast, to put on our shoes, to ride the train, bus or drive to work, where we are sedentary for hours (sometimes even through lunch). Then we repeat the commute, only to get home to relax from our "exhausting" day by sitting again: at the dinner table, in front of the television, or at our computers.

We go to the gym and we're on our butts again: on a stationary bike, rowing machine or leg press.

But even for fitness enthusiasts, the exercise isn't enough to counter all that inactivity, according to Dr. James Levine, who treats obesity at the Mayo Clinic in Rochester, Minnesota, one of the country's premier research hospitals.

“What is critical and maybe even more important than going to the gym, is breaking up that sitting time," Levine told NBC. "Sitting all day long is literally killing us."

Sound dramatic? It's not entirely.

Research shows that sitting for more than six hours a day makes you 40 percent more likely to die within 15 years than someone who sits less than three—even if you exercise. And for those aged 45 and older, a study of more than 220,000 people found that mortality risks are 15 percent higher for those sitting between eight and 11 hours compared to those sitting fewer than four hours per day.

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According to Levine, when we sit, our muscles stop working, our heart slows and our calorie and fat burning rate plummet (by 50 percent if sitting a full day). Consequently, our body fat increases and our cholesterol levels rise.

That comes as no surprise to Bridget Smith, celebrity trainer and national spokesperson for the American Heart Association. She said people who "sit all day at the office without any activity" increase their risk of obesity, diabetes and heart disease. It can also cause lower back pain. "Those muscles that you use to sit, like your hamstrings and legs, shorten and your hip flexors tighten up," she explained.

The New York Times reported last year that the average adult spends 50 to 70 percent of his or her time sitting. Those with the “highest sedentary behavior” had a 112 percent increase in their relative risk of developing diabetes; a 147 percent increase in their risk for cardiovascular disease; and a 49 percent greater risk of dying prematurely—even if they regularly exercised.

As disheartening as that news is to hear, Smith said it shouldn't discourage us from hitting the gym.

"You can't necessarily revert those diseases, but you can help prevent them," she said.

Levine suggests getting up and moving for 10 minutes every hour, but an employee who can never be found at his or her desk sounds like a nightmare for a boss (and like grounds for firing).