Lots of research has been done about the negative impacts that sitting for long periods of time can have on people’s health, both physical and mental. It’s generally accepted that sitting not only increases your chances of a variety of physical ailments, it also decreases your brain health over time. However, one study shows that this issue may not be as straightforward as previously thought.
Assistant Professor Aga Burzynska of the Colorado State University Department of Human Development and Family Studies led the study. She examined the association between physical activity and cognitive performance in 228 healthy adults aged 60 to 80. Each participant was asked to wear a special sensor on their hip for a week to capture their physical activity, and they were all given several tasks to measure their cognitive functions.
As expected, Burzynska found that older adults who engaged in moderate or vigorous activity on a regular basis had better cognitive speed, memory, and reasoning abilities. These are considered “fluid” memory tasks, and they tend to decline with age. It appears, therefore, that moderate to vigorous physical activity improves these types of cognition. However, the data also revealed a rather surprising juxtaposition.
Burzynska’s research showed that older adults who spent a lot of time being sedentary performed better than their more active counterparts on vocabulary and reasoning tasks, which are considered “crystalized” or knowledge-based abilities.
This could be a piece of good news for a population that has been spending more and more time sitting down over the years, both for work and for leisure.
The researchers believe this particular study stands out from others because it used scientifically validated sensors to measure physical activity rather than reported activity levels or an average activity-tracker meant for general public use.
“We already know that people like to overestimate their daily movement and underestimate the time they spend sitting,” Burzynska explains. “If you ask, ‘How long did you sit today?’ people will perhaps say 2 to 3 hours when the reality is more like 6 to 8 hours.”
This study also breaks cognitive measures down into 16 different tasks to help determine which parts of cognition are affected by physical activity and which are made healthier by using the brain more, which many people who sit a lot do, particularly those with sedentary computer jobs.
“There’s this big push within health and wellness that sitting is always bad for your body, that being a couch potato is not good,” Burzynska says, “and although our earlier studies indicated that the brains of those who spend more time sitting may age faster, it seems that on the cognitive level, sitting time may also be meaningful.”
The study showed no statistically significant correlation between lighter physical activities—such as laundry, cooking, or other household chores—and cognition. Replacing sedentary behaviors with light physical activity has always been advised for those who aren’t capable of doing more vigorous workouts, but this study seems to show that such forms of movement have little payoff in terms of brain health.
“We know that as we grow older, even if we do not have any cognitive impairments, people aged 60 and up already show some decreases in speed, executive functioning, and memory,” says Burzynska. “Those decreases are totally within a normal range, but this study was looking to understand how our behaviors and habits may correlate with cognitive outcomes in older age.”
Burzynska doesn’t suggest that anyone engage in a more sedentary lifestyle, but she believes that spending sedentary time focused and mentally stimulated could lead to a healthier brain, and it’s a way for people to help keep their brains healthy if they’re limited in the physical exercise they’re capable of doing. In the end, a good balance of physical activity and sedentary time spent stimulating the brain are what’s likely best for cognition as we get older.
Burzynska and her team controlled for socioeconomic and health factors, such as employment status, income level, aerobic fitness, blood pressure, and mobility issues. The study was published in Psychology and Aging.Whizzco