Are you reading this sitting down? If yes, you are not alone. Women's Health reports that Americans spend 56 hours each week sitting, and that this sedentary lifestyle (even among those who consider themselves active) is slowly killing us. According to the article, excessive sitting can lead to obesity, heart disease, depression, and diabetes and has opened up a new field of research, inactivity physiology, a field that studies "a deadly new epidemic researchers have dubbed 'sitting disease.'"

According to researchers, modern technological advances have changed our environment so that we are living contrary to our evolution as a species. Instead of spending our days upright and active, we barely have to move to earn our living, nourish ourselves, shop, or communicate with peers. Even folks who spend time at the gym each day aren't doing enough to counteract the harm of 10 hours spent sitting. Author Selene Yeager says "the consequences of all that easy living are profound ... the longer you spend sitting each day, the more likely you are to die an early death — no matter how fit you are."

How can this be? Yeager cites biomedical scientist Marc Hamilton, who says the body shuts down at the metabolic level after being motionless for extended periods of times. Our major muscle groups are meant for movement and, when they don't get it, they lose circulation, burn fewer calories, and use up less blood sugar. As a result, our lifestyles give us greater chances of contracting disease. Yeager writes, "For every two hours spend on your backside per day, your chance of contracting diabetes goes up by 7 percent." As if all that weren't bad enough, sitting pretty can wreak havoc on posture and spinal health because muscles designed for standing become weak and stiff when we lounge — a potential explanation for increased incidence of chronic lower-back pain.

But hope is not lost. Dr. James Levine of the Mayo Clinic in Rochester, Minn., has found that "non-exercise activity thermogenesis," or NEAT, can make a huge difference in the number of calories burned and help fight the detrimental affects of "prolonged parking." Basically, Levine suggests doing more with your body, everything from fidgeting to wiggling your toes, folding laundry, or just standing up (which burns three times as many calories as sitting). Every movement counts, so don't discount that steering wheel drum solo or restless pacing. The article suggests standing up every half hour throughout the workday to do things like check e-mail or take phone calls. If you really want to make a difference, swap out your desk chair for a yoga ball to engage your stabilizer muscles and force good posture even while you are sitting around.

Even these small efforts to air out your hindquarters can make a difference. In the course of a year, you could keep your metabolism in check, lower your chances of heart disease and, more important, "stave off the one-to-two pound weight gain" we tend to accumulate each year.

Your body's big enemy? You're sitting on it
Most of us spend our days on our behinds -- and it's killing us.