Exercise for Improved Mental Functioning
As a doctor, I rely on research done in the scientific method to back-up my recommendations.This is called “evidence-based medicine.”
Some things, however, are just known beyond what can be proven in the vacuum of research.For instance, I know that when people exercise, their physical and mental functioning improves.I know this because when I exercise, I am more mentally fit.Further, just as exercise correlates with mental wellness, lack of exercise brings about the opposite in my life.
Recently, science has helped to shed light on this fact.
This blog will review the current understanding on exercise and its effects on mental functioning.
The Exercise Experiment
In the lab, rats were stimulated with an interesting environment and challenged mentally with activities, access to an exercise wheel and different permutations of these offerings. Afterwards they were tested for their mental performance and comparing the rats with their different access to environments and equipment, only that exercise wheel made a difference in their performance.
Intrigued by their results, these same rats were injected with a substance that actually allowed the scientists to measure the brain growth.Once again, exercise was the main difference.
But, wait a second. Brain GROWTH? Can that be right?!
While we are conditioned to believe that nerve tissue growth does not generally occur, brain cells do in fact turn over, grow and generate just like any other cell in our body! This process is called "neurogenesis".
In general, this is considered a losing battle in our adult years.Most of us actually LOSE brain volume year-to-year after reaching our late 20’s. Specifically, the hippocampus, an area of the brain important in memory, loses 1% of its volume annually in the adult years. That's the bad news.
The good news? Despite this decline, neuron tracking studies have shown that exercise in rat models stimulates neurogenesis in the hippocampus.
The Only Problem?
We're not sure how much this really changes things.
To illustrate the problem, Einstein, upon his death, gave his brain to science for study and ironically, it was actually smaller than average! Thus, we know that brain size does not necessarily reflect brain function.The issue here with the neurogenesis involves connecting the wires, but if this increase in brain tissue is there but is non-functioning, limited in functioning or is not connected with existing neurons, what's the use?
Exercise Improves Neural Connectivity In Rats
In experiments, those rats that were simply exposed to mazes showed neuron growth, but those neurons fired only when exposed to the same maze.
With exercise, however, neurogenesis DID achieve better connectivity, firing with several activities including cognitive exercises.
Brain-Derived Neurotropic Factor (BDNF)
But what about humans?
Admittedly, animals are quite a leap from humans when it comes to these revelations.We cannot remove our brains and map neural pathways.The link and the molecular explanation for these findings may exist in the substance called Brain-Derived Neurotropic Factor (BDNF).This substance, among other things, stimulates neurogenesis.
With exercise, rat BDNF increased as expected.Research in humans has also shown an increase in BDNF after exercise.
In a study done on a modest aged population, one group was assigned to vigorous walking and the other to stretching.In the walking group, BDNF and hippocampus size increased.In the stretching group, only normal age-related atrophy (loss) occurred. No studies have looked at which type(s) of exercise is optimal for cognitive function, but an educated guess points to the first.
It Needn't Be Exhausting!
If you're interested in pursuing an exercise regimen to support your physical and cognitive health, I'd like to point out that exercise needn’t be exhausting to be effective!
Start or continue where your abilities allow.Check out my past blog on what defines exercise http://www.hellolife.net/living-healthy/b/is-it-exercise/
As Einstein (that really smart fellow with the smaller than average brain) said, “Life is like riding a bicycle. To keep your balance you must keep moving.”
Gretchen Reynolds, NY Times