Although studies have been done on exercise and physical health, “different intensities of daily physical activity and cognitive health is less understood, especially in older adults,” Burzynska said in a press release.
“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. 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 said.
The study tested 16 cognitive tasks instead of one or two measures of cognition. In addition, it measured and controlled for socioeconomic and health factors, such as employment status, income level, aerobic fitness, blood pressure and mobility issues.
“Our study has pretty high-quality measures that cannot be done ‘quick and dirty’,” Burzynska said.
Older participants wore a sensor on their hip for a span of seven days, during which the sensor captured the daily time each person spent sitting or in light versus moderate to vigorous physical activity.
The results of the cognitive tasks helped the research team determine if there were a correlation between physical activity and “fluid” vs. “crystallized” cognition.
Participants who engaged in moderate to vigorous physical activity performed better on fluid tasks — such as speed and memory, problem solving, and reasoning skills — suggesting that exercise might stave off some of the typical effects of brain aging.
Most participants, however, spent less than 2.7% of their time engaged in moderate to vigorous activities.
Those older adults who sat more hours each day performed better on crystallized, or knowledge-based, activities, like vocabulary tests or reading comprehension.
Unfortunately for less active people, light physical activities such as doing laundry, cooking or other household chores showed no link to 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,” Burzynska said, “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 researchers speculate that sedentary people likely are engaging in educational, stimulating activities, like reading, playing games or puzzles, or attending plays, which might serve to boost crystallized cognition.
Burzynska said the study reinforces the recommendation that regular exercise is good for general health, but engaging in more cognitively demanding activities may also be an option for older adults who can’t be physically active,
“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,” she said. “I hope it sends some positive message for those of us who have had limited opportunities to exercise during the pandemic.”