The Ever-Changing Brain
The living brain is continuously going through changes based on what we experience every day. Early in life, cells in our brain are extremely active making connections with each other as we make sense of our world, mentally organize our experiences, learn new skills, and socialize with others. Through this process, the brain volume changes, and connections become more efficient.
As we learn and experience new things, our brain cells reach out to other brain cells by growing extensions, called dendrites. These extensions (dendritic connections) make it easier to remember things and make sense of new information more efficiently (in a way, it makes us smarter). The addition of those dendrites gradually builds up the volume (size) of our brain.
As we figure out what information we need and don’t need, we begin to rely on certain dendritic connections, so a process called “pruning” happens. This is when the unused dendrites wither away, which maintains a bit of balance as newer connections continue to develop. Experts used to think that at a certain point our brain was done developing, and what you had was all you were going to get.
As science progresses we have come to know that we can keep that process going (to a smaller degree, but it continues) as long as we’re exposed to new experiences and information, and give our brain what it needs through what we eat, how active we are, and how we handle stress. We can slow down the normal aging process and can even improve how our brain operates once that aging has started.
Over time, the volume of our the brain can begin to decrease (in other words, it gets smaller), as more and more pruning becomes the norm while fewer new connections are made. This is considered “normal” aging, and in extreme cases, brain disorders can develop.
One structure in the brain that is vital for memory formation is the Hippocampus. This little part is also often found to shrink as we age, if we don’t take care of it.
Combined with destructive processes that can occur from chronic inflammation, exposure to substances, and unhealthy living, we can end up with anything from occasional forgetfulness to full-blown dementia.
Fewer connections and less bulk in the brain and its parts means more effort is needed in paying attention, making sense of and storing new information, decision making and calling up recent memories. In other words, it’s much harder to focus, understand, decide on a response, control impulses, make and retrieve memories.
What Does Exercise do for Your Brain?
Imaging technologies (MRI, CT Scans), are giving scientists a look into the brain and its structures and we can compare the brains of active an inactive people. They can also see what’s going on at the microscopic level between the two groups, as well as shortly after exercise. Multiple studies show that when you compare people who are fit vs. unfit there are differences:
- Overall brain volume is higher in those with better cardiorespiratory fitness.
- The hippocampus is larger in those who are active.
- There is more blood flowing through the brain during mental tasks.
- There is more of a substance called BDNF (Brain-derived neurotrophic factor) in those who are active. This substance is required or nerve growth.
- There are more dendritic connections (branches) forming between brain cells in active subjects.
These differences are easy to discern with regular exercisers, however some changes can be seen after only one bout of exercise and can last for a few days!
Much of the research on brain function in relation to activity is comparing groups of people (often the studies target older men) with high vs. low cardiorespiratory fitness. Some research follows subjects for periods up to four weeks to monitor the effects of activity on how the brain is working.
The main findings:
- Higher fitness participants show better attention and focus on quick mental processing tasks.
- Subjects with high fitness levels process information more quickly than those with low levels of fitness.
- Participants with high fitness levels have better non-verbal memory than those with low fitness levels.
- People with higher fitness respond more accurately in quick-response timed tasks.
One thing worth pointing out: the more mentally demanding a task is, the bigger the difference is between the groups.
How to Get Started
The most encouraging aspect of this research is that you can see changes after exercising, just one time. Of course, to get the fuller, longer-lasting benefits, you need to keep it up.
Many of these studies assigned subjects to a walking program as the exercise modality. No hard-core workouts necessary!
If you’re just getting started, whether you are in good health or have an ongoing diagnosis, it’s important to set the right goals for yourself. Talk to your doctor about what you should strive for, and work your way there safely based on his/her guidance.
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- Exercise-induced enhancement of synaptic function by the inverse BAR protein, MTSS1L (Chatzi, Zhang, et al, 2019).
- The Influence of Exercise on Cognitive Abilities (Gomez-Pinilla and Hillman, 2013).