You Still Might Be Sitting Too Much

Can you move regularly — even a lot — and still be considered “sedentary?”

This fascinating question was raised by the New York Times (or, at least, a reader): Does Taking Fewer Than 5,000 Steps a Day Make You Sedentary?

As the piece notes, physical activity is fairly clear: It means movement, or even standing. Sedentary activity means sitting: Such as driving one’s car or working at one’s desk. And while that might seem to indicate that engaging in physical activity necessarily means that one is not sedentary, that’s actually not the case.

Dr. Russell Pate, a professor of exercise science at the Arnold School of Public Health at the University of South Carolina, told the New York Times that one can be regularly active, yet “still engage in a great deal of sedentary behavior. And I believe that such a pattern is quite common in our current society.”

The piece states:

“In other words, you can take 5,000 steps in a day or 10,000, meaning that you would cover either about 2.5 or 5 miles. But in both cases, if you concentrate those steps into a single session of exercise and then spend the rest of your waking hours slumped in a desk chair or in front of a television, you will be more sedentary than active.”

In other words: Even if you’re regularly active, too much sitting is still something to watch out for — and avoid.

One reason becomes clear in a recent study in the Journal of Applied Physiology, titled “Motor Unit Number and Transmission Stability in Octogenarian World Class Athletes: Can Age-Related Deficits Be Outrun?

In this study, authors “measured functioning motor units (MU) numbers and neuromuscular transmission stability in the tibialis anterior of world champion [masters athletes] (~80y), and compared the values to healthy age-matched controls (~80y).”

As expected, the masters athletes’ legs were strong. However, as the New York Times reports:

“More interesting to the researchers, the athletes also had almost 30 percent more motor units in their leg muscle tissue, and these units were functioning better than those of people in the sedentary group. In the control group, many of the electrical messages from the motor neuron to the muscle showed signs of “jitter and jiggle,” which are actual scientific terms for signals that stutter and degrade before reaching the muscle fiber. Such weak signaling often indicates a motor neuron that is approaching death.”