Share of moderate and vigorous physical activity in middle age associated with brain power
summary: Moderate to vigorous exercise is associated with improved cognition and brain power during middle age. This intensity level has been associated with improved working memory and mental processes. Reducing intensity to lower intensity or sedentary behavior for 6-7 minutes per day has been associated with poorer cognitive performance.
Source: BMJ
The amount of time spent in moderate-to-vigorous physical activity each day is linked to brain power in midlife, suggests research published online in Journal of Epidemiology and Community Health.
This intensity level appears to be best for working memory and mental processes, such as planning and organizing, and replacing it with just 6-7 minutes of light intensity activity or sedentary behavior each day is associated with poorer cognitive performance, the findings suggest.
Previously published studies link moderate-to-vigorous daily physical activity, or MVPA for short, to health, researchers say, but few of them included time spent sleeping, which makes up the largest component of any 24-hour period.
So they adopted a combination approach to see if MVPA relative to all other daily movement behaviors might be better for cognitive performance in middle age.
They relied on participants in the 1970 British Cohort Study, which includes people born across England, Scotland and Wales in 1970 and whose health is tracked throughout childhood and adulthood.
In 2016-18, 8,581 participants reached the age of 46-47, at which time they were asked to fill out detailed health, background and lifestyle questionnaires, and to wear an activity tracker for up to 7 days and for at least 10 consecutive hours per day.
They underwent various cognitive tests of verbal memory (immediate and delayed word recall tasks) and executive function (verbal fluency and processing speed/accuracy).
Scores for each test were combined to produce an overall global score for memory and executive function.
Of those who agreed to wear the activity tracker, 2,959 participants were disqualified due to a device error, insufficient wearing time, or failure to fully complete the questionnaires.
The final analysis included 4481 participants, of whom just over half (52%) were women. Two-thirds (66%) were married and 43% were educated up to the age of 18. More than two-thirds (68%) were casual or non-hazardous drinkers and half had never smoked.
Analysis of activity tracker data showed that participants recorded an average of 51 minutes of MVPA, 5 hours and 42 minutes of light physical activity, 9 hours and 16 minutes of sedentary behaviors, and 8 hours and 11 minutes of sleep over a 24-hour period.
Time spent in the MVPA relative to other types of behavior was positively associated with cognitive performance after adjusting for educational attainment and workplace physical activity. But additional adjustment for health issues weakened these associations.
The researchers noted that inactive behavior in relation to sleep and light physical activity was positively associated with cognitive performance: a trend likely reflecting greater engagement in cognitively stimulating activities such as reading or working rather than any apparent benefit from watching television.
The associations were stronger for executive function than for memory.
Compared to the average across the sample, participants in the upper half of their cognitive performance scores spent more time on physical and psychological exercise and sedentary behaviors and less time sleeping, while the lowest 25% of scorers scored on light physical activity.
To better understand the co-correlations between movement and cognition, the researchers reallocated the time from one component to another, minute by minute, to estimate the effect this might have on global cognitive performance scores.
This revealed that increases in scores after the MVPA theoretically displaced other activities.
Individuals’ cognition showed a 1.31% improvement in the order of cognition compared to the sample mean after 9 minutes of sedentary activities with more vigorous activities – a positive trend that became more substantial with a much greater decrease in sedentary activities.
Similarly, there was a 1.27% improvement from replacing gentle activities or 1.2% from replacing 7 minutes of sleep. These improvements showed further improvement with greater time exchange.
The sedentary behavior was also beneficial for the cognition score, but only after it was replaced by 37 minutes of light physical activity or 56 minutes of sleep.
Participants theoretically began to decline in cognitive rankings within the study sample by 1-2% after only 8 minutes of more vigorous activity being replaced by sedentary activities. The ranking continued to fall with a larger decline in MVPA.
Similarly, replacing vigorous activities with 6 minutes of light physical activity or 7 minutes of sleep, was associated with similar decreases of 1–2% in the order of cognition, exacerbated again with greater loss of MVPA.
The researchers say that activity trackers can only record time spent in bed rather than the duration or quality of sleep, which could help explain the association with sleep.
The MVPA is usually the smallest percentage per day in real terms, and the hardest intensity to get. Perhaps partly for this reason, missing any MVPA time at all seems detrimental, even within this relatively active group,” they explain.
This is an observational study and, as such, cannot prove cause. The researchers highlight several caveats: Activity-tracking metrics cannot provide context for every component of a movement. Despite the large sample size, people of color were underrepresented, which limited the generalizability of the results.
However, they concluded: “This powerful method confirms the critical role of MVPA in supporting cognition, and efforts should be made to enhance this component of daily movement.”
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Source: BMJ
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“Exploring the associations of daily movement behaviors and cognition in midlife: a compositional analysis of a 1970 British cohort studyWritten by John G. Mitchell et al. Journal of Epidemiology and Community Health
Summary
Exploring the associations of daily movement behaviors and cognition in midlife: a compositional analysis of a 1970 British cohort study
background
Movement behaviors (eg, sedentary behavior (SB), moderate and vigorous physical activity (MVPA), light physical activity (LIPA), and sleep) are associated with cognition, however the relative importance of each component is unclear and has not yet been explored. installation methodologies.
objective
(1) assessing the associations of different components of daily movement and the participant’s overall cognition, memory, and executive function, and (2) understanding the relative importance of each individual component of cognition.
Methods
The British Cohort Study of 1970 (BCS70) is a prospective birth control cohort study of adults born in the United Kingdom. At age 46, participants agreed to wear an accelerometer and to complete tests of verbal memory and executive function. Synthetic linear regression was used to examine cross-sectional associations between 24-hour movement behaviors and standardized cognition scores. Isotemporal substitution was performed to model the effect of time reallocation between components of daily motion on cognition.
results
The sample included 4481 participants (52% female). Time in the MVPA for SB, LIPA, and sleep was positively associated with cognition after adjustments for education and occupational physical activity, but additionally attenuated associations for health status. SB relative to all other movements was positively associated with cognition. Reallocation of modeling time between components revealed an increase in the percentage of cognition after theoretically replacing MVPA with 9 minutes of SB (OR = 1.31; 95% CI 0.09 to 2.50), 7 minutes of LIPA (1.27; 0.07 to 2.46) or 7 minutes of SB. sleep (1.20); 0.01 to 2.39).
conclusions
Relative to time spent on other behaviors, greater MVPA and SB were associated with higher cognitive scores. MVPA’s time loss, due to its relatively small size, seems to be the most injurious. Efforts should be made to maintain MVPA time, or to reinforce it rather than other behaviors.