This is your brain on exercise: how working out impacts your brain

We have all heard it: exercise is good for you.  It has been said to improve cardiovascular health, lower blood pressure, and decrease risk for cardiovascular disease[1].  Whether or not you enjoy cycling on a stationary bike, going for a jog outside, or balancing in a vinyasa yoga class, you cannot argue with the fact that physical activity has beneficial effects on your body.  But did you know it also has profound effects on your brain?

Not only does exercise improve physical health outcomes, but it also results in marked positive changes in brain health.  Currently a hot topic in the neuroscience research world, studies are showing that exercise increases neuroplasticity, or the ability of the nervous system to change by reorganizing its structure, function or connections, and is particularly helpful at improving memory via neurogenesis (birth of new neurons) in the brain regions involved in memory.  Exercise has also been shown to improve mood, blunt the stress response in the brain, and even slow the progression of neurodegenerative disease[2,3].  How does it do this?  According to research, the answer lies in various molecular mechanisms. 

For example, one way that exercise promotes neuroplasticity is through the induction of a neurotrophic factor called brain-derived neurotrophic factor (BDNF)[4].  BDNF is essential to neuronal growth and synaptic plasticity and is widely expressed throughout the brain, particularly in areas that are involved in cognition and memory including the hippocampus and cortex.  During exercise, BDNF circulation is upregulated, and this has also been found in mouse models of disease, for instance in models of Alzheimer’s Disease[5].  The mechanism underlying exactly how exercise upregulates this neurotrophic factor remains unclear, but a few metabolic pathways are currently being studied[6].   

Another example of a mechanism by which exercise benefits the brain, and particularly mood and affect, is via neurotransmitters.  Neurotransmitters are the chemical messengers of the brain, some of which are crucial chemicals for our brain regions involved in mood and affect.  For instance, serotonin is a key neurotransmitter for mood homeostasis.  Many anti-depressant medications act on serotonin pathways, for example SSRIs (selective serotonin reuptake inhibitors).  Animal studies have shown that exercise training increases cerebral serotonin levels in particular brain regions, including the hippocampus, striatum and frontal cortex[7].  This might help to explain how exercise impacts our mood, and simply makes us feel good. 

If you have more questions like, how does exercise exactly affect these mechanisms?  Or, what types of exercise are most beneficial?  I suggest you look to one of the experts in the field, Dr. Wendy Suzuki.  Dr Suzuki is a professor of Neuroscience at NYU and has published a few books on the topic, one being: Healthy Brain, Happy Life.  Check it out to learn more! 

References:

[1] M.A. Nystoriak, A. Bhatnagar, Cardiovascular Effects and Benefits of Exercise, Frontiers in Cardiovascular Medicine. 5 (2018). https://www.frontiersin.org/articles/10.3389/fcvm.2018.00135 (accessed October 26, 2022).

[2] J.C. Basso, W.A. Suzuki, The Effects of Acute Exercise on Mood, Cognition, Neurophysiology, and Neurochemical Pathways: A Review, BPL. 2 (2017) 127–152. https://doi.org/10.3233/BPL-160040.

[3] K.S. Frederiksen, L. Gjerum, G. Waldemar, S.G. Hasselbalch, Effects of Physical Exercise on Alzheimer’s Disease Biomarkers: A Systematic Review of Intervention Studies, J Alzheimers Dis. 61 (2018) 359–372. https://doi.org/10.3233/JAD-170567.

[4] M.W. Voss, C. Vivar, A.F. Kramer, H. van Praag, Bridging animal and human models of exercise-induced brain plasticity, Trends Cogn Sci. 17 (2013) 525–544. https://doi.org/10.1016/j.tics.2013.08.001.

[5] A. Dinoff, N. Herrmann, W. Swardfager, D. Gallagher, K.L. Lanctôt, The effect of exercise on resting concentrations of peripheral brain-derived neurotrophic factor (BDNF) in major depressive disorder: A meta-analysis, J Psychiatr Res. 105 (2018) 123–131. https://doi.org/10.1016/j.jpsychires.2018.08.021.

[6] C.D. Wrann, J.P. White, J. Salogiannnis, D. Laznik-Bogoslavski, J. Wu, D. Ma, J.D. Lin, M.E. Greenberg, B.M. Spiegelman, Exercise induces hippocampal BDNF through a PGC-1α/FNDC5 pathway, Cell Metab. 18 (2013) 649–659. https://doi.org/10.1016/j.cmet.2013.09.008.

[7] M. Chennaoui, C. Drogou, D. Gomez-Merino, B. Grimaldi, G. Fillion, C.Y. Guezennec, Endurance training effects on 5-HT(1B) receptors mRNA expression in cerebellum, striatum, frontal cortex and hippocampus of rats, Neurosci Lett. 307 (2001) 33–36. https://doi.org/10.1016/s0304-3940(01)01901-2.

Edited by Alexandra Fink