This month’s research corner highlights the best evidence to date for why you need to exercise starting from diagnosis (even before) and not stop when you are diagnosed with Parkinson disease (PD)…. And, it explains what we mean when we say “Exercise is a physiological tool in your fight against Parkinson disease.” Since it is one of my favorites, I have taken the time to summarize it for everyone. See you at the PWR!Gym! Becky
Habitual exercisers versus sedentary subjects with Parkinson’s disease: Multimodal PET and fMRI study. Matthew A. Sacheli, MSc, Danielle K. Murray, MD, Nasim Vafai, MASc, Mariya V. Cherkasova, PhD, Katie Dinelle, MSc, Elham Shahinfard, PhD, Nicole Neilson, RN, Jessamyn McKenzie, LPN, Michael Schulzer, PhD, Silke Appel-Cresswell, MD, Martin J. McKeown, MD, BEng, Vensa Sossi, PhD, and A. Jon Stoessl, MD. Movement Disorders, 2018; Online DOI: 10.1002/mds.27498
Researchers at the University of British Columbia and Vancouver Coastal Health in Vancouver, CA examined the brains of people with Parkinson disease that were habitual versus sedentary exercisers. Habitual exercisers were defined as people that exercise > 3x/week for > 180 minutes. Sedentary exercisers were defined as people performing at lower frequency or duration. Participants were from 45 to 70 years old and presented with disease severity ranging from mild symptoms (on one side of the body) to moderate symptoms (on both sides of the body and required assist to catch their balance when pulled backwards).
Part 1. All participants underwent two Positron emission tomography (PET) brain scans, one at baseline and another post exercise. The exercise involved 30 minutes of stationary cycling at 60% of maximal intensity. PET imaging was performed OFF medications and required the injection of the drug (Raclopride) that was labelled with a radioisotope so that it could be visualized and quantified during imaging. Raclopride is a dopamine (DA) antagonist, which means it blocks the binding of DA to its’ receptors. The exercise was performed between PET scans to elicit the bodies own (endogenous) dopamine release. Authors hypothesized that the more DA released in response to exercise, the fewer DA receptors there would be to bind with the radioactive labeled Raclopride. A large change in the Raclopride binding potential from pre exercise (baseline) to post exercise, would indicate an increased amount of exercise-induced release of DA. This binding potential change was compared in habitual and sedentary exercisers.
Results. Habitual exercisers showed the largest change in the binding potential, suggestive of a more robust dopamine system with increased release of DA in response to exercise.
- Bottom Line. Several exercise-induced physiological factors may have contributed to stronger, more complex and efficient dopamine signaling (neuronal communication) in habitual exercisers, such as: increased release of the bodies own dopamine, increased number of DA receptors, improved neuronal survival, increased neurotrophic factors, reduced oxidative stress, and increased mitochondria function.
Part 2. All participants also underwent MRI/fMRI scans OFF medications to measure brain activity associated with blood flow in the ventral striatum, a part of the brain involved in DA release during anticipation of a reward. Participants performed a monetary reward task that required the random selection of one of four cards associated with different probabilities of winning a reward. At the start of each block of 20 trials (1 block per probability), participants were explicitly informed about the probability for selecting a winning card. The intensity of the blood flow signal was calculated for each block at baseline and during the anticipation phase of the task (after they selected a card and before they received notification if they obtained the money reward). The percent signal change for the anticipatory phase (as apposed to baseline) was measured across each of the different probabilities and compared between habitual and sedentary exercisers.
Results. Habitual exercisers, as opposed to sedentary, showed greater activation in anticipation of reward in the ventral striatum.
- Bottom Line. This type of enhanced response to reward, may contribute to greater feelings of well-being as a result of exercising! This may increase a person’s willingness to exert effort (for reward). So the more you exercise, the better you feel and the more you want to exercise!
Part 3. In addition to brain imaging, participants were tested on a variety of clinical assessments both on and off medications to measure motor symptoms related to dexterity, function (sit-stand-walk-turn-sit), cognition, depression, and apathy.
Results. Habitual exercisers showed less bradykinesia, better function, and less apathy.
- Bottom Line. This suggests that habitual exercisers may have an advantage from the start; with a more robust DA response to exercise, better mobility, less apathy and better mood, and therefore, be more likely to participate in exercise.
- For people that are sedentary at the time of diagnosis, these data suggest it is ESPECIALLY important that they are immediately referred to a PD-specialized physical therapist to establish baseline and personalize goals for increasing participation through self-efficacy and behavioral coaching.
- For all of you that exercise at the PWR!Gym 3x/week, you still need to do more! Maintain an active social life and do more of what you LIKE in structured activities outside of your class! Try walking outdoors or on a treadmill, cycling, playing pickle ball, doing yard work, playing with your grandkids at the park, hiking with poles..…you get it right? The more you do, the more you can do! AND, that is what may reduce the amount of mediations you need over time!
- Sacheli MA, Murray DK, Vafai N, et al. Habitual exercisers versus sedentary subjects with Parkinson’s Disease: Multimodal PET and fMRI study. Mov Disord. 2018:1-6. doi:10.1002/mds.27498