In healthy cells, there is a balance between the production of free radicals called reactive oxygen species (ROS) and the antioxidants that neutralize them. Oxidative stress occurs when there is an increase in the number of ROS compared to antioxidants. Psychological stress can contribute to these imbalances. Even acute bouts of high stress can negatively affect brain health, as the resulting increase in oxidative stress causes a host of inflammatory processes within neurons (1).
These changes are similar to some of the issues that already occur with Parkinson’s disease, where there is an increase in oxidative stress in neurons that produce dopamine in the substantia nigra. Additionally, damaged mitochondria within these neurons don’t get tagged correctly to be discarded, leading to further increases in oxidative stress, inflammation and damage. Compounding the effects of stress with the processes of Parkinson’s disease can lead to a toxic environment and degeneration within key parts of the brain (2).
This all sounds very bad, but the good news is we have evidence there is something you can do about it. Exercise is a treatment that reverses many of these negative side effects and can be protective in its own right. In animal models of PD, aerobic exercise increases antioxidant production within brain cells, decreases ROS, and increases cell turnover, which decreases inflammation and oxidative stress (3,4). Additionally, exercise encourages the release of brain-derived neurotrophic factor (BDNF). In animal models of PD, BDNF production due to aerobic exercise was shown to preserve dopamine-producing neurons in the basal ganglia and even induce neuroregeneration, which resulted in improved motor performance (3, 4).
So now that we know another reason why exercise is good for you, you might be wondering what type and duration of exercise will get you the benefits. An animal model of PD found that 30 minutes of treadmill exercise daily for two weeks was an effective treatment to reduce oxidative stress (4). Additionally in humans, researchers found that eight weeks of resistance training twice per week (3 sets of 5-8 repetitions on the leg press, seated leg curl and calf press) resulted in a ~15% decrease in blood biomarkers of oxidative stress in people with mild to moderate PD compared to a 14% increase seen in the control group (5). Another study found that eight weeks of 40 minutes of moderate-intensity interval cycling three times per week resulted in an increase in blood levels of BDNF in people with mild to moderate PD and improved scores in the Unified Parkinson’s Disease Rating Scale compared to pre-training (6). How can you act on this information? First and foremost, find an accessible form of exercise that you enjoy, and is sustainable for you. This could also be as simple as going for a walk when you feel stressed. Try to find a type of exercise you can perform for 30-40 minutes with a 5-10 minute warm up and cool down three times per week (7).
Now more than ever is a time to prioritize your self-care. Life is stressful, especially while also managing difficult disease. One of the best ways we can support our body in times of stress is engaging in regular movement. Happy exercising!
References
1. Gerecke KM, Kolobova A, Allen S, Fawer JL. Exercise protects against chronic restraint stress-induced oxidative stress in the cortex and hippocampus. Brain Res. 2013; 1509:66-78.
2. Dias V, Junn E, Mouradian MM. The role of oxidative stress in Parkinson’s disease. J Parkinsons Dis. 2013; 3(4):461-91.
3. Palasz E, Wysocka A, Gasiorowska A, Chalimoniuk M, Niewiadomski W, Niewiadomska G. BDNF as a promising therapeutic agent in Parkinson’s disease. Int J Mol Sci. 2020; 21(2):1170.
4. Oliveira da Costa R, Gadelja-Filho CVJ, Moura da Costa AE et al. The treadmill exercise protects against dopaminergic neuron loss and brain oxidative stress in Parkinsonian rats. Oxid Med Cell Longev. 2017; 2138169.
5. Bloomer RJ, Schilling BK, Karlage RE, Ledoux MS, Pfeiffer RF, Callegari J. Effect of resistance training on blood oxidative stress in Parkinson disease. Med. Sci. Sports Exerc. 2008; 40(8): 1385–1389.
6. Zoladz JA, Majerczak J, Zeligowska E, Mencel J, Jaskolski A, Jaskolska A, Marusiak J. Moderate-intesity interval training increases serum brain-derived neurotrophic factor level and decreases inflammation in Parkinson’s disease patients. J Physiol Pharmacol. 2014; 65(3):441-8.
7. Alberts JL, Rosenfeldt AB. The universal prescription for Parkinson’s disease: Exercise. J Parkinsons Dis. 2020; 10(s1):S21-S27.