A new year begins, and you’ve decided to be healthy. You’ve convinced yourself this is the year you will define a workout routine and stick to it: you will reach your goals by the beginning of the summer! The summer has just started and if you are like the majority of us, you have already quit your ambitious plan some time ago. Would it be easier for you to carry on if you knew all the benefits your brain was also reaping?
Including physical activity in one’s daily routine and having a more active lifestyle have been on the top of new year's resolutions lists for the last few years. In France, for example, this goal comes before dieting and travelling (1). While many start strong and a few manage to continue, most people abandon their fitness-related goals in the first half of the year. The most striking benefits that sports can have on your body are well known, but what about the brain? Do you know your brain may also be positively impacted?
Sports have been an important part of my life for as long as I can remember, but as I focused more on my career, I started to neglect physical activity. However, during the COVID-19 lockdown something struck me, and I felt a sudden need to start exercising again to reduce my stress and better cope with my daily work challenges. I began to run and quickly noticed its remarkable effect on my mental and physical health.
Impact of exercise on physiology
Walking, running, and other endurance activities are known to induce a series of positive effects on our bodies. Even though weight control and muscle development are the most common motivations for those who venture into an exercise routine, there are other benefits to keep in mind. One of the best known physiological outcomes of exercise is the improvement in respiratory and cardiovascular function. Particularly, regular sports practice can help maintain a healthier heart, reduce blood sugar levels and regulate metabolic imbalances. Finally, physical activity can mitigate inflammation, boost immune responses and stimulate the production and release of growth factors and signalling molecules, which will directly impact our sleep, appetite, cognition, stress response and mood (2).
The hat trick: the effect of exercise on cognition, stress response and mood
Exercise is associated with the increased synthesis and release of hormones, neurotransmitters, and neuronal growth factors– molecules that are essential for proper brain function. In particular, aerobic exercise, such as running, swimming or cycling, has been shown to increase the levels of brain-derived neurotrophic factor (BDNF), a crucial player in many cellular pathways, that assists in the growth, differentiation and healthy function of nerve cells (3,4,5).
At the cognitive level, physical activity has been proven to enhance memory performance, motor learning, attention and information processing. A study performed on older adults demonstrated that one year of regular walking potentiates the activation of the hippocampus, the main brain region associated with memory formation and recall, and strengthens its connectivity to other brain areas (4). Apart from improving long-term memory, practising some physical activity - even if for a short time period - has a positive impact on the brain region responsible for motor control and makes the acquisition of motor skills easier (5).
Improvement in mood state, affective response and stress levels have also been linked to exercise of different intensities and durations. Behavioural and functional studies have revealed that, in response to a stress factor, people who underwent some physical training feel and perform better, and their blood pressure does not increase as much as in the sedentary group (6). Furthermore, their cortisol levels, the so-called stress hormone, remain lower and the release of endorphins, the body’s natural painkillers and mood lifters, is stimulated (5).
Sports involvement in neuroplasticity, neurogenesis and inflammation
Functional studies have also linked exercise to greater plasticity in the outer region of the brain, the cortex, which is in charge of cognitive tasks like the processing of sensory stimuli, learning and behavioural flexibility. Neuroplasticity implies that the brain modifies its structure and function through the creation and reinforcement of synapses, the points of communication between brain cells. This translates into more dynamic and flexible brain circuits that, for instance, enable us to identify a new language when we hear it for the first time, allow us to start learning it, and eventually lead us to quit because it seems too complicated and time-consuming. (4).
Another striking effect of exercise concerns neurogenesis, the generation of new neurons. Over the last decade, robust evidence has found that physical activity stimulates the production of new cells in the hippocampus, which correlates with better cognitive performance. Moreover, exercise can decrease neuroinflammation. Many studies have reported an amelioration of the inflammatory state in different models of ageing and neurodegenerative diseases, in which neuroinflammation is exacerbated. Together, these pro-neurogenic and anti-inflammatory properties of exercise exert neuroprotective effects on the brain (7).
Alternative medicine: can exercise be used as disease treatment?
As a matter of fact, exercise has been shown to have a beneficial effect on people suffering from different neurological and psychiatric disorders including major depressive disorder, Alzheimer’s disease, Parkinson’s disease, multiple sclerosis and schizophrenia (8).
Many studies point toward a positive correlation between regular physical exercise and an attenuation of depressive symptoms. This observation is particularly prominent in elderly individuals and in cases of major depressive disorder (8). According to a group of Brazilian researchers, integrating moderate-intensity aerobic exercise and high-intensity strength exercise appears to be the most promising workout plan to alleviate the burden of this disorder (6).
Studies carried out on animal models of Alzheimer’s disease revealed that physical activity can prevent the accumulation of beta-amyloid deposits and phosphorylated Tau protein, the two main hallmarks of this disease (6). Exercise also appears to facilitate the clearance of these pathological deposits, the production of growth factors and neurogenesis. Lastly, it boosts memory function and exerts an anti-inflammatory action in the brain, which may consequently promote neuronal resilience (3,9).
In the case of Parkinson’s disease, studies in animal models suggest that physical activity ameliorates some of the neuropathological, behavioural, and molecular deficits. Clinical research supports these findings and reports improved neuroplasticity, motor function, and cognitive performance in PD patients that exercise (3,6).
In diagnoses of dementia and other neurodegenerative disorders, improving flexibility, strength, and balance reduces the risk of falling and enhances motility, which positively impacts the patient’s quality of life. Apart from the direct positive consequences physical activity has on the nervous system, exercise may also be mediating protective effects through this "indirect" pathway; this contribution should not be overlooked (6).
Pharmacology is the standard treatment for neurologic diseases. However, there are many drawbacks to these treatment courses, such as side effects, high cost, poor patient compliance, and possibly addiction (8). Drug therapy alone is thus not ideal; therefore, carefully tailored exercise routines are now being put forward as alternative (or cooperative) non-invasive treatments. These could act at the level of prevention, symptom relief, or as a coadjuvant therapy, especially in age-associated brain diseases.
Some people start exercising because they seek to change something about their appearance, improve their overall physical health, or just to become more active. But as we continue to realise, the effects that physical activity may have on our brains, alongside the known health benefits we obtain, are just as appealing and, personally, way more interesting.
The great news is that you do not have to wait for a new year to start fresh!
Though exercising is not for everyone, and the intensity level should be adjusted to each individual’s abilities, I think there is nothing wrong with starting small and developing smoothly. The scientific literature referring to the drawbacks of sports mostly concerns elite athletes and possible psychological disturbances stemming from extreme pressure, limited recovery from intense training loads, and untreated concussions.
For the common man or woman, it is all about taking care of one's body and mind, and not drifting towards overexercise. Whether you decide to step outside for a walk in nice weather, dive into your local swimming pool to refresh your thoughts, or put on your sports gear and follow a home workout video, there are plenty of options for all tastes and levels.
So stretch your body, warm up your muscles, and let your body naturally produce memory enhancers, antidepressants and stress relievers to give your brain that extra boost!
1. Gabriel, J. (2021, January 5). En 2021, le sport reste la bonne résolution n°1. Doctissimo. https://www.doctissimo.fr/forme/news/sport-bonne-resolution-numero-un
2. Malm, C., et al. (2019). Physical Activity and Sports—Real Health Benefits: A Review with Insight into the Public Health of Sweden. Sports, 7(5), 127. https://doi.org/10.3390/sports7050127
3. Baek, S. S. (2016). Role of exercise on the brain. Journal of Exercise Rehabilitation, 12(5), 380–385. https://doi.org/10.12965/jer.1632808.404
4. Voss, M. W., et al. (2013). Neurobiological markers of exercise-related brain plasticity in older adults. Brain, Behavior, and Immunity, 28, 90–99. https://doi.org/10.1016/j.bbi.2012.10.021
5. Basso, J. C., & Suzuki, W. A. (2017). The Effects of Acute Exercise on Mood, Cognition, Neurophysiology, and Neurochemical Pathways: A Review. Brain Plasticity, 2(2), 127–152. https://doi.org/10.3233/bpl-160040
6. Matta Mello Portugal, E., et al. (2013). Neuroscience of Exercise: From Neurobiology Mechanisms to Mental Health. Neuropsychobiology, 68(1), 1–14. https://doi.org/10.1159/000350946
7. Ryan, S. M., & Nolan, Y. M. (2016). Neuroinflammation negatively affects adult hippocampal neurogenesis and cognition: can exercise compensate? Neuroscience & Biobehavioral Reviews, 61, 121–131. https://doi.org/10.1016/j.neubiorev.2015.12.004
8. Zhao, J., et al. (2020). Exercise, brain plasticity, and depression. CNS Neuroscience & Therapeutics, 26(9), 885–895. https://doi.org/10.1111/cns.13385
9. Valenzuela, P. L., et al. (2020). Exercise benefits on Alzheimer’s disease: State-of-the-science. Ageing Research Reviews, 62, 101108. https://doi.org/10.1016/j.arr.2020.101108