An exercise regime will do more than strengthen your muscles: within weeks, it could also help your brain work more efficiently.
A study suggests that as people become fitter, their bodies react differently to a 15-minute burst of exercise, releasing more of a protein linked to mental sharpness. In turn, this was linked to the brain using less energy when performing cognitive tests.
Dr Flaminia Ronca, the study’s lead author, from University College London, said the changes were seen after six weeks and help explain why regular exercise boosts mental performance.
“We’ve known for a while that exercise is good for our brain, but the mechanisms through which this occurs are still being disentangled,” she said.
“Our results help explain why, if we increase our fitness levels, exercise can help us focus and concentrate on what we’re doing, control impulsive behaviours, regulate emotions and be better able to make decisions.”
The research focused on a protein known as brain-derived neurotrophic factor (BDNF). Sometimes called a naturally occurring “fertiliser for the brain”, it helps nerve cells grow, survive and form new connections. Scientists already know that it plays an important role in learning and memory and that there appear to be links to better mental health as well.
The study found that after exercise less brain activity was required for a given task
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However, the idea that it directly produces “neural efficiency”, where less brain activity is required for a given task, is much newer.
In the study, published in Brain Research, Ronca and her colleagues followed 23 adults aged between 18 and 55 who were largely sedentary and relatively unfit. They were split into two groups: one continued their usual routines, while the other followed a 12-week cycling programme that gradually increased in intensity.
Those in the exercise group completed three cycling sessions a week. They also did a weekly session of strength exercises such as press-ups and squats.
Researchers measured cardiovascular fitness and blood samples were taken to measure BDNF levels.
Participants also completed tasks designed to test attention, reaction times and memory. At the same time, researchers monitored activity in the prefrontal cortex, an area of the brain involved in focus, decision-making and impulse control.
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After three months, those in the exercise group were much fitter. However, their resting levels of BDNF had not changed.
The key difference appeared after exercise. Participants who had completed the training programme released much more BDNF after 15 minutes of exertion than earlier in the study; those who improved their fitness the most tended to show the biggest increases.
Participants also did a weekly session of strength exercises
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Higher levels of the protein were linked to changes in activity in the prefrontal cortex during tasks requiring attention and self-control. Greater BDNF was associated with lower activity in these regions. This suggests the brain was working more efficiently, performing the same tasks while using less energy.
Dr Felix Chan, an assistant professor in pharmacology at the University of Birmingham, who was not involved with the research, said: “This is an exciting study which shows that exercise has a positive effect on BDNF and the brain. However, this is a small sample size … so further verification is needed.
“Additionally, this only shows correlation between BDNF level and brain function; so whether BDNF is playing an active role in driving brain improvement … remains to be seen.”