Climb down from your standing desk, take a comfortable seat in a cushy armchair and exercise your brain by reading these new findings on cognition in mid-aged people.
While studies on mid-life physical activity and cognition are a dime a dozen on google-scholar, it’s only through a study like Mitchell et al. have designed that we see the actual value of a favorite pastime of both kings and peasants alike: sitting.
University College London (UCL) researchers set out to see how our daily movement relates to our cognition and how differences in the specific types of physical activity could improve it.
If you account for 100% of daily activities, then it’s clear that the time spent on any one type of physical activity is time away from another. In this way, there is a “co-dependent nature of daily movements.”
Sports enthusiast and first author John J. Mitchell, and colleagues, used a “time displacement” approach to determine what type of physical behaviors, when replaced with others, have the most potential to increase cognition scores for the average mid-life individual (median 47).
An accelerometer categorized the participant’s physical activity into four types:
- MVPA: moderate and vigorous physical activity
- LIPA: Light-intensity physical activity
- SB: sedentary behavior
- Sleep
To assess cognition, the researchers measured verbal memory and executive function to form a composite score for each of the 4481 participants.
Dividing the cognition score into four quartiles, researchers found different combinations of actives for each cognitive grouping.
The higher two quartiles in cognition practiced more MVPA and SB and less sleep. The participants in the lowest cognition quartile spent the highest amount of time in LIPA and significantly less at MVPA.
MVPA was by far the most beneficial for mid-life cognition, strongly connected to executive function slightly more than memory. Increasing MVPA improved cognition while replacing it with any other behavior was associated with lower cognitive scores. For example, an average of 7 more minutes replacing LIPA with MVPA showed better cognition.
More surprising was the benefits “associated” but not necessarily “caused” by SB. Sedentary behavior was also positively associated with cognition and connected considerably to executive function.
This pro-sitting finding comes in stark contrast to prevalent anti-sitting health PSAs. The value of sitting might come from the cognitively challenging activities one can enjoy while sitting, not any sedentary benefits.
MPVA is precious time, taking up little of our days but requiring incredible exertion. In general, replacing any other activity with MVPA increased cognition scores. The benefits of pro-MVPA switches were especially true for those in sedentary jobs. And the opposite was also true; replacing MVPA with other behaviors was predictive of lower cognitive scores.
There are several possible explanations for the benefits of MPVA, as found in other research:
- increase nutrient flow to the brain
- the release of neurotrophic factors that increase synaptic connection
- growth of new hippocampal neurons
Or maybe physical exercise is more cognitively stimulating, requires more planning and commitment, perhaps more socially engaging.
In the end, as Monty Burns once exposed, "Oh, yes, sitting---the great leveler. From the mightiest pharaoh to the lowliest peasant, who doesn't enjoy a good sit?"
Sources: Journal of Epidemiology & Community Health, FOX Broadcasting Company via Youtube and The Simpson’s Archives
