'Mentally active' sitting may reduce dementia risk

NBC News -   Sitting for hours on a regular basis can be bad for your body and brain. A new study suggests that keeping your brain engaged helps counteract some of the harms of sedentary behavior.

Engagement means activities such as knitting or solving a puzzle, instead of mindlessly scrolling or passively watching a screen.

Scientists at the Karolinska Institute in Stockholm surveyed 20,811 Swedish adults, mostly women between the ages of 35 and 64, about their weekly physical activity and how much daily time they spent in “mentally active” and “mentally passive” sedentary behavior. They first questioned the participants in 1997 and followed up 19 years later to assess dementia risk and status.

Sedentary behavior — long periods of sitting, lying down or reclining — is linked to “major risk factors for dementia,” like high blood pressure, heart disease, diabetes and obesity, said Mats Hallgren, a principal researcher at the Karolinska Institute and an author of the study.

However, brain activity is a crucial element in protecting against that damage.

The brain “works like a muscle,” he said. Not actively using it for extended periods of time can eventually negatively affect the parts linked to memory and learning.  In the questionnaire, being mentally active while sedentary included office work, sitting in a meeting, as well as knitting and sewing. Activities like using a computer to solve a puzzle were considered intellectually stimulating.

Watching TV or listening to music while sedentary counted as mentally passive.