Exercise and Neuroplasticity
By Jamie Bussin, featuring Dr. Henry Mahncke, PhD
Dr. Henry Mahncke is a leading expert in the field of cognitive neuroscience. With more than two decades of experience in the field, Dr. Mahncke has dedicated his career to understanding and enhancing human brain function. I discussed how exercise can support brain health with him in Episode #453 of The Tonic Talk Show/Podcast. This article is a summary of our discussion.
Exercise appears to be associated with better brain health and a lower risk of dementia, but the science is more nuanced than simply saying that exercise prevents dementia. Dr. Mahncke explains what we know about the connection, why the evidence has limitations, which forms of exercise may be beneficial, and why the learning that takes place while we exercise could be an important part of the equation.
Can Exercise Reduce the Risk of Dementia?
Studies consistently find that people who exercise more are less likely to develop dementia, but researchers don’t necessarily know whether exercise lowers dementia risk or whether the earliest effects of dementia cause people to exercise less. The correlation between exercise and a lower risk of dementia exists, but there is no definitive proof of causation.
How Does Exercise Benefit the Brain?
It is clear, however, that exercise does support brain health. Dr. Mahncke identifies three clear mechanisms:
- Heart health: Exercise can reduce high blood pressure and cholesterol and lower stroke risk.
- Blood-sugar metabolism: Exercise helps the body metabolize blood sugar more efficiently, which matters because Dr. Mahncke says the brain consumes about 40% of the body’s energy and blood sugar.
- Brain plasticity: Exercise releases growth factors that promote positive brain plasticity and help rewire the brain.
What Type of Exercise Is Best for Brain Health?
The good news, according to Dr. Mahncke, is that aerobic exercise, such as running, swimming and intense walking, supports brain health, as does intense non-aerobic exercise such as weight training and resistance training. Both have been shown to benefit cognitive function and brain health.
There may not be one specific type of exercise that is best for brain health.
How Much Exercise Do You Need for Brain Health?
The not-so-good news is that the frequency and intensity of exercise do matter. You can’t just go through the motions. While he didn’t give specific advice, Dr. Mahncke recommends exercising several times a week, with an aggregate amount of at least two hours, if not more, at sufficient intensity to “break a sweat.”
Is All Exercise Good for the Brain?
Not all activity and movement are the same. It’s contextual. There’s an interesting distinction between leisure-time exercise and physical activity associated with employment.
A physically demanding job, such as being a delivery driver who carries packages up and down stairs, may also involve exposure to noise, air pollution and stress, whereas recreational exercise, such as playing regular soccer, might involve additional benefits from social interaction, enjoyment and continuous learning. Roughly equivalent levels of exertion, in those two different contexts, won’t impact brain health in the same way.
Does Exercise Train the Brain as Well as the Body?
I recently decided to change my workouts to include more strength training. One of the new exercises I do is the bench press. In order to get the best results, build muscle and avoid injury, I’ve hired a personal trainer to show me proper form.
In order to do a proper bench press, your body has to be specifically positioned. The core needs to be braced, the hands placed at the proper width on the bar, the shoulders pulled back, the elbows flared at the right angle from the body, with your feet firmly planted on the floor and your back arched. The motion path is specific. The pacing and breath work matter, too. And all of that has to be learned. This suggests that the bench press isn’t just training my body, but my brain as well.
Dr. Mahncke agrees that learning proper weightlifting technique requires the brain to organize resources and rewire itself. While there is no study he’s aware of that confirms this proposition, he agrees that while physical exercise provides benefits through cardiovascular health, blood sugar and growth factors, the learning involved in controlling the body may itself contribute to brain health.
What Is “Muscle Memory” Really?
If you do enough bench presses, the form and process of the exercise require less conscious effort. Eventually, you develop “muscle memory.” What we call muscle memory involves parts of the brain responsible for controlling and organizing movement becoming rewired to produce precise movements more accurately and efficiently. Dr. Mahncke connects this directly to neuroplasticity.
Muscle memory is in the brain.
Can Exercise Build Brain Resilience?
The short answer is yes. Dr. Mahncke describes brain reserve/resilience as the brain’s ability to resist the effects of ageing and the eventual onset of dementia. He argues that neuroplasticity and new learning contribute to brain health and resilience, whether that learning happens through brain exercises, playing soccer or perfecting a bench press.
Key Takeaways About Exercise and Brain Health
- Exercise is consistently associated with a lower risk of dementia, although observational studies cannot establish cause and effect.
- Aerobic exercise and resistance/weight training can both benefit brain health.
- Exercise may support the brain through cardiovascular health, better blood-sugar metabolism and brain plasticity.
- Dr. Mahncke suggests that the learning involved in mastering physical movements may provide an additional brain benefit.
- “Muscle memory” is actually a process involving the brain and neuroplasticity.
- The context of physical activity may matter; exercise during leisure time can occur in a very different environment from physically demanding work.
