In July, PMD Alliance presented a talk by Dr. Giselle Petzinger, titled “The Neuroplastic Effects of Exercise.” Dr. Petzinger focuses on the role exercise plays in promoting neuroplasticity, the brain’s ability to form new connections and pathways, and how this strengthens cognitive and automatic components of motor control. We at Stanford Parkinson’s Community Outreach listened to the webinar and are sharing our notes.
To watch the webinar recording on YouTube, follow this link.
Below are my notes from the online speaker event.
Stanford Parkinson’s Community Outreach
The Neuroplastic Effects of Exercise – Webinar Notes
Presented by the Parkinson and Movement Disorder (PMD) Alliance
July 17, 2020
Summary by Deven Shah, Stanford Parkinson’s Community Outreach
The speaker is Giselle Petzinger, MD, an associate professor of neurology at the Keck School of Medicine at USC. She is a movement disorder specialist who divides her time between clinical care of patients and laboratory research. Primarily, her laboratory work focuses on better understanding how to promote brain repair following incidents such as injury and how to translate these findings into therapeutic treatments.
This talk will mainly address exercise’s role in Parkinson’s disease. This includes our most recent findings and how exercise might help in Parkinson’s disease.
Parkinson’s is traditionally thought of as a problem with dopamine. If you analyze the brain circuit-by-circuit, you quickly realize that dopamine is involved with almost every neural function, from high-level thinking to movement.
Neuroplasticity is the idea that the brain can reorganize itself by forming new neural connections throughout life. These neural connections can come through neurogenesis, where new neurons are created (less likely), or synaptogenesis, where new synapses, or connections, are created (more likely). Part of this involves the brain’s attempt to reach homeostasis, or equilibrium, following external stress. This is the way we encode new experiences or learn new behaviors. Thus, when the brain is damaged, the brain will use the idea of neuroplasticity to relearn lost behavior in response to rehabilitation.
Since the late 80s, there has been a lot of interest in exercise and Parkinson’s. It has been shown to reduce the risk of getting Parkinson’s, and later was shown to elicit helpful effects in people who already have Parkinson’s disease. These effects were quickly shown to manifest in motor-related symptoms, such as gait or balance, and current research, especially in the aging field, is trying to determine whether those extend to cognition.
To look for reasons how/why exercise might improve outcomes, you have to look at the molecular mechanisms behind neuroplasticity. If we figure out how exercise stops Parkinson’s, we can target it with therapeutics. So you have to look at synapses, brain health, and overall effects on circuitry to figure out how to mimic its effects.
Researchers were also able to show that dopamine was being released more efficiently and there were a higher number of dopamine connections/synapses in mice who had regularly exercised on a treadmill.
The prefrontal cortex is involved in thinking, and the motor cortex/striatum is involved in movement. Resting blood flow, which supplies energy and nutrients to both of those areas, increases with exercise, supporting the idea that regular exercise elicits neuroplastic effects that change neuronal activity, in this case for the better. If the exercise is something that requires skilled, controlled movement, the neuroplastic effect increases further.
Astrocytes supply all of the nutrients and energy in the bloodstream to the neurons that need them.
As a result, exercise ameliorates some of the long-term effects of Parkinson’s. On the cellular level, it does this by increasing connections and blood flow, a marker of cell activity. It also releases certain molecules such as trophic factors, which help neurons grow, fuels, like glucose, or anti-inflammatory chemicals, released by the immune cells exercise stimulates.
Question and Answer Session
Q: What exercise is best?
A: Skilled motor practice allows patients to target the neural circuits affected most by Parkinson’s disease, such as the basal ganglia, which is responsible for learning and remembering complex motor movements. Skilled practice also improves the cognition / higher level thinking aspect of Parkinson’s disease. There is obviously still benefit from aerobic exercise, which increases total blood flow, but at the end of the day skilled exercise is the most important. The best routine is 20 minutes of aerobic exercise, where you should be sweating and going hard enough where you can’t keep up a conversation. For the second part of your workout, try to push yourself to master a new skill or workout movement. Alternatively, you can change up an old skill to increase your “cognitive load,” or how much you have to think about the motor movement you are doing. For example, you could try doing yoga with your eyes closed, or running on a hilly trail instead of on your treadmill again.
Q: Does exercise “use up” all of your dopamine reserves? Can you not use it for the rest of your day?
A: Dopamine is important for the growth and stabilization of neural connections, and, as a result, the creation of neural circuits. Without dopamine, nothing is facilitating that process, and subjects are unable to learn new motor tasks. As a result, dopamine is an intermediary that allows patients to achieve a desired motor skill, not an end-all behavioral output, so there is no concept of “using it up.” If you aren’t feeling good after your workout, you’re probably overdoing it. It doesn’t mean that your dopamine reserves are depleted.
Q: Does exercise improve mood? What about apathy, anxiety, or depression?
A: There is a lot of information that does prove this hypothesis. Dopamine improves mood, so in optimizing dopamine circuits exercise improves mood. Exercise also elicits the release of norepinephrine and serotonin, two other neurotransmitters that facilitate feelings of happiness and contentment.
Q: How can you get started with exercising?
A: Getting somebody with expertise with exercise and Parkinson’s disease is extremely helpful. After getting a referral from your PCP or neurologist, these physical therapists tend to be of great service because they can create custom workout plans, etc. Finding a social group, whether it is in a gym or just with friends, tends to help people get started and find the fun in exercising as well.
Q: How can you start exercising amid COVID-19?
A: It really depends on what machines you have in your house. A stationary bike, an old treadmill, really anything you can find helps. As long as you can think of ways to make it skillful, and it gets your heart rate up, then it will work. Things like dance or online classes allow you to still exercise even without equipment. You can always walk outside as long as it is safe to do so.
Q: If you are just walking, are you still getting the benefits of skilled and aerobic exercise?
A: Make sure walking is effortful. Leave your dog behind, and really walk at a brisk pace. This will allow you to get your heart rate up. Mix it up to be able to learn new motor skills and increase your “cognitive load,” or how hard you have to mentally work to skillfully exercise.
Q: Is there evidence that exercise slows down the progression of Parkinson’s disease?
A: Nobody knows. We are working to attain that data, but currently we don’t have that. To keep it simple, we know that exercise ameliorates the motor symptoms of Parkinson’s. Cognition, or how Parkinson’s affects thinking, is still being researched.
Q: Do you think people should visit a physical therapist as soon as they are diagnosed with Parkinson’s?
A: They definitely understand exercise better than we do. They can motivate people and prescribe the right exercises for people. They also know what exercises involve skill, such as tennis, dancing, or cycling.
Q: Does any data exist about inversions?
Q: What about other ways to train your motor learning circuits? Such as learning to play an instrument.
A: They are still helpful. But think about generalizability. Studies show that motor learning of exercises increases motor learning in all other areas. Same thing with playing an instrument, which is also extremely complex. But with things like luminosity, sudoku, or crossword puzzles, getting better at these games tends to not correlate with getting better at everything else.
Q: Why is all of this so important? How does it make a difference?
A: What lifestyle studies are about is proving that healthcare is about yourself – while you don’t have control over the medications that your doctor gives you and their efficacy you do have control of your lifestyle and how that helps or hurts your health. Everyone should go outside and make a difference in their own and others’ health.