Many people know that exercise is good for the body.
It can strengthen the heart, improve muscle health, and help control weight. However, scientists are also learning that physical activity may be very important for the brain.
A new study led by researchers at University College London (UCL) has found that improving physical fitness may help the brain release more of an important protein that supports brain health.
The research was published in the scientific journal Brain Research. It shows that when people become fitter, their brains may respond more strongly to exercise.
This stronger response may help improve brain activity and support important mental functions such as attention and decision-making.
Inside the brain there are many chemicals and proteins that help brain cells grow, connect, and survive.
One of the most important of these is called brain-derived neurotrophic factor, often shortened to BDNF. Scientists sometimes describe BDNF as a type of “brain fertilizer” because it helps brain cells grow stronger and form new connections with each other.
BDNF plays several important roles. It supports the creation of new neurons, which are the cells that send messages in the brain. It also helps build new synapses, which are the connections between neurons. These connections allow brain cells to communicate with each other. Healthy synapses are essential for learning, memory, and thinking.
Previous studies have already shown that exercise can increase BDNF levels in the brain. Even short periods of aerobic activity, such as running or cycling, can trigger the release of this protein. However, scientists did not fully understand whether becoming physically fitter over time would change how the brain responds to exercise.
To explore this question, the UCL research team designed a 12‑week exercise program for people who were not physically active. The study was led by Dr. Flaminia Ronca from UCL Surgery and Interventional Science and the Institute of Sport, Exercise and Health.
Thirty adults took part in the study. Most of them were men, with 23 male participants and seven female participants. All volunteers were described as inactive or unfit at the start of the study. This allowed the researchers to observe how their bodies and brains changed as their fitness improved.
Participants completed a structured training program that involved cycling three times each week for 12 weeks. The exercise sessions were designed to gradually improve aerobic fitness.
To measure how participants’ fitness levels changed, researchers used a test known as VO2max. This test measures how much oxygen the body can use during intense exercise. VO2max is widely used by scientists as a reliable indicator of aerobic fitness. Participants completed this test every six weeks during the study.
At the same time, the researchers measured levels of BDNF before and after exercise sessions. Participants also completed several cognitive tests designed to measure attention, thinking skills, and memory. In addition, the researchers monitored activity in a part of the brain called the prefrontal cortex.
The prefrontal cortex plays a key role in many important mental abilities. It helps people focus their attention, control impulses, make decisions, and manage emotions. Because of its role in higher-level thinking, scientists are very interested in how exercise affects this area of the brain.
The results of the study showed something very interesting. At the beginning of the study, participants released a certain amount of BDNF after exercising. However, after completing the 12‑week training program and becoming fitter, their brains released a much larger surge of BDNF following the same type of exercise.
In other words, the participants’ baseline BDNF levels did not change very much. Instead, what changed was the brain’s reaction to exercise. Once participants became fitter, their brains produced a stronger burst of BDNF after a workout.
This increased response was linked to improvements in aerobic fitness measured through VO2max. As participants’ fitness levels improved, the amount of BDNF released during exercise also increased.
The researchers also observed changes in brain activity. Participants who had stronger BDNF responses showed different patterns of activity in the prefrontal cortex during tasks that required attention and self-control. These tasks tested how well participants could focus or stop themselves from responding too quickly.
Interestingly, the changes were not as clear during memory tasks. This suggests that the short-term brain benefits of exercise may be stronger for attention and executive control than for memory, although more research is needed to fully understand these effects.
Overall, the findings suggest that improving physical fitness may help the brain become more responsive to exercise. When people are fitter, even a short workout of about 15 minutes of moderate to vigorous aerobic activity may produce a stronger boost in BDNF.
Dr. Ronca explained that scientists have known for some time that exercise benefits brain health, but the exact biological processes behind this effect are still being studied. One of the most exciting discoveries from this research is that the brain’s response to exercise can improve relatively quickly. In fact, noticeable changes were seen after only six weeks of training.
The study provides useful insight into how regular physical activity may support brain health. However, it is also important to consider some limitations. The study included a relatively small number of participants, and most were men. Larger studies with more diverse participants will be needed to confirm the results.
Even so, the findings add to growing scientific evidence that regular exercise supports both physical and mental health. Becoming more physically fit may help the brain produce greater amounts of beneficial proteins during exercise, which could strengthen brain connections and improve certain cognitive functions.
In simple terms, the study suggests that the fitter we become, the more our brains may benefit from exercise. This may help explain why regular physical activity is often linked to better mental performance, improved focus, and healthier aging.
If you care about brain health, please read studies about how the Mediterranean diet could protect your brain health, and Omega-3 fats and carotenoid supplements could improve memory.
For more information about brain health, please see recent studies about antioxidants that could help reduce dementia risk, and higher magnesium intake could help benefit brain health.
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