by New York Times

We've all heard that sitting too long is bad for you. We're not evolved to do it, it can undermine our exercise gains, it causes dead butt syndrome. Sitting might not quite be "the new smoking," but too much of it can still shorten your life.

"Sitting is actually aging you faster," said Katy Bowman, a biomechanist and author of "My Perfect Movement Plan." Whether it's bone or joint health, muscle mass or energy level, she added, "a lot of what you perceive as aging is going to be heavily influenced by your sitting time."

And we spend a lot of time sitting. Numbers vary around how much average Americans sit per day, but it may be as long as nine and a half hours. Studies suggest women sit less than men do, but most agree we all sit more than previous generations did.

The consequences can be serious. A study published at the beginning of the year followed 480,000 people in Taiwan over 13 years and found those who sit most of the work day had a 34 percent higher risk of dying from cardiovascular disease than those with less sedentary jobs did --- and a 16 percent higher risk of mortality overall.

One way to lower the risk, the authors wrote, was to add 15 to 30 minutes of physical activity per day to your existing routine. Other studies go further, suggesting sedentary people need to double the standard weekly exercise recommendations.

"The bottom line is that too much sitting is a big new health risk," said Neville Owen, as senior scientist at the Baker Heart and Diabetes Institute in Melbourne, Australia.

Put simply, uninterrupted sitting is bad for your heart, joints, muscles metabolism and mental health.

The American Heart Association notes that prolonged sitting raises the risk of developing heart disease or stroke, even for those who exercise regularly. It can take as little as 30 minutes of uninterrupted sitting to affect how blood vessels function. And the longer you sit, the higher the cardiovascular risks, especially if you are sitting for more than 10 hours.

Sitting for extended periods has also been linked to lower back pain. Small studies suggest the height of your lumbar disc might be compressed after sitting more than four hours without interruption.

Furthermore, your large leg and gluteal muscles can stop activating after just 30 minutes of sitting, Dr. Owen said. Over time, they can weaken and cause back or knee pain.

Sitting also doesn't burn much energy. Over time, a sedentary lifestyle can affect your ability to regulate blood sugar and break down fat, potentially leading to weight gain and Type 2 diabetes. American workers today burn about 100 fewer calories per day than they did 50 years ago. That's roughly equal 30 minutes of walking,said Thom Rieck, and exercise specialist at the Mayo Healthy Living Program in Rochester, Minn.

Lastly, sitting affects mood and cognition, increasing the odds of depression and anxiety.