While we regularly hear how older adults have to stay active if they want to stay physically fit and mentally strong, new research shows that there is some benefit for those who lead a more sedentary lifestyle.
When it comes to brain health and cognition, a new study of older adults from Colorado State University suggests that some level of sedentariness can contribute to great mental acuity in some areas, as long as basic physical activity benchmarks are being met.
The research, which examined the physical activity and cognitive performance of 228 healthy older adults aged between 60 to 80, found that those who spent more time sitting performed better on vocabulary and reasoning tasks than those who were more physically active.
Researcher Dr Aga Burzynska said that while the association between physical activity and cardiovascular health was well documented, the link between different intensities of daily physical activity and brain health was less understood, especially in older adults.
“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,” Dr Burzynska said.
“Those decreases are totally within a normal range, but this study was looking to understand how our behaviours and habits may correlate with cognitive outcomes in older age.”
The researchers in this study measured daily physical activity using scientifically validated sensors that are more accurate than consumer-based activity trackers such as Fitbits.
These devices were used because of the propensity for people to overestimate their daily movement and underestimate the time they spent sitting in tests where the subjects were allowed to self-report.
“If you ask, ‘How long did you sit today?’ people will perhaps say two to three hours when the reality is more like six to eight hours,” she added.
Older adults who participated in the study wore the sensor on their hip for a span of seven days, during which the sensor captured the daily time they spent sitting or in light versus moderate-to-vigorous physical activity.
Participants were expected to complete 16 cognitive tasks, broken down into two sections – ‘fluid’ and ‘crystallised’.
‘Fluid’ abilities, such as speed and memory, problem solving, and reasoning skills, tend to decline through adulthood.
‘Crystallised’ activities were more knowledge-based activities such as reading comprehension or vocabulary tests, which tend to strengthen with age as adults acquire more knowledge and experience.
Participants who engaged in moderate to vigorous physical activities performed better on fluid tasks, suggesting that exercise might stave off some of the typical effects of brain ageing, but there was no such advantage when it came to ‘crystallised’ activities.
The researchers speculate that this may be because when people are sedentary, they are more likely to be engaging in mentally-stimulating activities such as reading or playing games and puzzles, which might serve to boost performance in crystallised cognition.
“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,” Dr Burzynska said.
“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.”
“I don’t think I would in any way suggest that we should engage in more sitting, but I think trying to be as physically active as possible and making sure that you get stimulated in your sedentary time – that it’s not just spent staring at the TV – that this combination might be the best way to take care of your brain.
“I hope it sends some positive message for those of us who have had limited opportunities to exercise during the pandemic.”
How much of your day do you spend sitting? How do you think you would rate on these cognition tests? Have you spent more time sitting this year than in previous years due to the pandemic?
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