You know that foggy, unfocused feeling you get after sitting too long at your desk? It may very well be your brain getting thinner, reducing its ability to process thoughts and memory, according to new research.

In a study by University of California, Los Angeles (UCLA), researchers associated long periods of sitting with the thickness of the brain’s medial temporal lobe (MTL), the region in which memory is processed. The UCLA researchers studied 35 women and men between 45 and 75 years old who sat on average 7.2 hours a day. Thinner MTLs were associated with study participants who sat for long periods. This part of the brain naturally thins with age, but this thinning is linked to memory loss.

While several studies have linked sedentary behavior with increased cardiovascular risk factors, including high blood pressure, diabetes and obesity, this is the first to look at sitting’s affect on brain health.

“Sedentary behaviors appear to have direct effects on neurobiological processes,” states the study published in the Public Library of Science journal One.

Today, Americans spend an average of 13 hours a day being sedentary.  Excessive sitting can contribute to more than 30 chronic diseases, according to James A. Levine, M.D., Ph.D., a physician and researcher who invented the treadmill desk. Getting up and moving more can help reverse these consequences, he says.

Ways to Prevent ‘Sitting Disease’

The term “sitting disease” has been coined by the scientific community and is commonly used to refer to metabolic syndrome and the ill-effects of an overly sedentary lifestyle. Taking breaks to move helps rev up metabolism, improve posture and increase blood flow.

“Incorporating just 15 minutes of movement into the day can relieve a lot of aches and pains that come from sitting too much,” said L.B. Irigoyen, an exercise physiologist and wellness coach with Baptist Health South Florida. “Pains you may have after a long period of sitting is your body’s way of expressing that its range of motion is being limited. This leads to a higher chance of injury which can decrease quality of life.”

A lot of lower back pain comes from putting too much load on the spine, according to Mr. Irigoyen. Sitting for prolonged periods compresses the vertebrae.

He says spending a minimum of 10 to 15 minutes a day in body maintenance is essential to maintaining strength, conditioning joints and muscles and keeping tendons and ligaments healthy.  Some of the things helping at the workplace include standing desks, gadgets to help you exercise at your desk and apps that remind you to get up and move.

If you don’t have access to a standing desk, stepping away and going for a brief walk will help, say experts. Another study published in Medicine & Science in Sports & Exercise suggests that the impaired blood flow in leg arteries can actually be reversed by breaking up your sitting regimen with five-minute walking breaks.

Mr. Irigoyen offers other tips for reducing what he refers to as “optional” sitting:

• For every 30 minutes of sitting, move for at least two minutes. Get up and take a walk around the office or outside. Dedicate part of your lunch break to walking. Incorporate more walking into your daily routine by parking further away from the building and taking the stairs.
• Choose to stand when you can. Stand while attending meetings or social gatherings, while eating breakfast or talking on the phone. Leaning against a table or stool is less detrimental than sitting in a chair, Mr. Irigoyen says.
• Prioritize body position when you can. Sit with shoulders back and a relaxed jaw. Stand with feet facing straight forward, chin tucked to create a long neck and squeeze glutes to neutralize any pelvic tilts. And remember to breathe. Taking a few deep breaths at your desk helps relax your shoulders and ease tension that causes muscles to tighten, causing aches and pains.
• Spend time stretching. After a period of sitting, stretching helps to decompress joints. Sit on the floor and spend time stretching while watching TV. Stand and push away from your desk to stretch hamstring and calf muscles. Stretch arms overhead to loosen shoulder and neck tension.

“These practices employ the basic principles of movement which are meant to protect joints and have minimal movement in the spine,” Mr. Irigoyen said. “The goal is to maintain a neutral spine and pelvis when sitting, standing or walking.”

The UCLA researchers say future studies that look at the type of activity taking place with sitting and classifying it as “mentally active” or “mentally inactive” sitting should be explored. Reducing sedentary behavior by 25 percent could potentially prevent more than one million cases of Alzheimer’s worldwide, they note.

In addition to making changes to your physical activity, changing your mindset about taking care of your body is also key, Mr. Irigoyen adds.

“With more awareness about your body and how it feels, you can take charge of yourself and do what’s necessary to stay healthy and feel good,” he said.