LONDON — Exercising in your forties could improve your brain’s ability to process and retain information, a new study explains. Researchers in London says that middle-aged people engaging in moderate-to-vigorous physical activity daily do better on tests measuring cognition. Conversely, those who sit around all day or only perform light exercise appear to have less brain power.
Past research studying the benefits of exercise during midlife has discovered a link to better cognitive health. However, these studies did not explore other alternative explanations that could explain the boost in brain power such as how much time a person spends asleep. The current study finds its mid to high-intensity workouts that improve cognition, especially in brain areas involved in working memory, planning, and organization.
The authors collected data from the 1970 British Cohort Study that tracked the health of 4,481 people born across the United Kingdom in 1970, from childhood onward. From 2016 to 2018, participants (now 46 to 47 years-old) had to provide a detailed update on their health, background, and lifestyle. They also wore an activity tracker for a week and at least 10 consecutive hours a day to record their daily movement. To study their cognition, participants completed a series of cognitive assessments that tested their verbal memory and executive function.
Sitting isn’t always bad for the brain
The activity tracker data revealed that people spent an average of 51 minutes doing moderate-to-vigorous physical activity and five hours and 42 minutes doing light physical activity. People in their mid-forties spent a good chunk of their time doing sedentary activities, clocking in an average of nine hours and 16 minutes. Participants did spend about eight hours and 11 minutes asleep every night, which many studies say is the recommended amount of sleep.
Interestingly, those who spent most of their time doing sedentary activities were more likely to show higher cognitive scores. The researchers suggest this may be because these people were engaging in cognitively stimulating activities like reading or working rather than spending hours watching TV. The associations were stronger for executive function like planning and processing information rather than for memory.
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People who scored the highest on the cognitive tests engaged in moderate-to-vigorous physical activity, sedentary behaviors, and spent less time asleep. The lowest performers spent the most time in light-intensity physical activity like taking a walk instead of other exercises.
Should you trade some sleep for sedentary activity?
Looking at moderate-to-vigorous physical activity by itself, the study authors found the variable to be the most important in improving a person’s cognition. Spending more time in high-intensity workouts and less than nine minutes doing sedentary activities improved a person’s cognition by 1.31 percent. People who replaced gentle activities for more active exercises showed a 1.27-percent cognitive improvement. The research team also observed a 1.2-percent boost in cognition when people sacrificed seven minutes of sleep for high-impact movements.
Sedentary activities like sitting continued to have a positive association with cognition, but only after substituting it for 37 minutes of light exercise or 56 minutes of sleep. However, people who sacrificed eight minutes of vigorous activity for sedentary behaviors showed a one to two-percent drop in their cognitive scores.
The findings suggest staying extremely active helps with cognition, but since this is an observational study, there are several limitations to consider when interpreting the results. First, the activity trackers only captured the time people spent in bed rather than when they were actually asleep or the quality of their sleep. It’s possible people were in bed for eight hours but could not fall asleep for hours. Sleep deprivation also leads to worse cognition. Additionally, the activity trackers only estimate the intensity of movement and it’s possible a workout such as running a half-marathon versus lifting weights could have different effects on the body.
It’s also not realistic that a person is engaging in vigorous exercises for the whole day and likely spends a short period of time doing intense workouts. Because of this small window for high-impact movements, the study authors note that any loss of time not doing vigorous activities would appear extremely detrimental to the results.
The study is published in the Journal of Epidemiology & Community Health.