The Best Kind of Exercise for Brain Health

Since ancient times doctors have spoken about the benefits of exercise for both body and mind. Hippocrates, a renowned Greek physician of ancient times, has been quoted saying, “Walking is a man’s best medicine” and “If you are in a bad mood, go for a walk. If you are still in a bad mood, go for another walk.” While the doctors of these times were undoubtedly correct in prescribing exercise as medicine, their rationale was primarily based upon prior clinical experience and observations. If enough patients with a case of the blues reported feeling better after exercising, it would not take long for a caring and curious physician to notice the relationship between body and mind. 

Rapid advances in science and technology have allowed scientists to explore the human body in ways that were simply not possible before. While many questions remain unanswered, we now know that the mind and body are connected in various ways, and exercise improves the health of both. Even better, because we have a better picture of how and why movement bolsters our mental wellbeing, we can better identify the kinds of activities that can benefit us the most.

This article will cover the ways exercise benefits the mind, contrast the effects of aerobic versus strength training, and conclude by sharing the best exercises for brain health based on the most current science available.

How does exercise improve brain health?

One of the ways that exercise improves brain health is by adjusting the levels of numerous neurotransmitters, chemicals that regulate our thoughts and emotions. Exercise increases the levels of several neurotransmitters, such as serotonin, dopamine, and norepinephrine. This effect is even more potent if the kind of activity is challenging. Running up a hill will likely result in a greater change in the brain’s chemistry than a literal walk in the park (1).

Exercise can also have a powerful effect at the genetic level, thus affecting the very cells that make up our brain. Scientists have recently discovered that activating one’s muscles with exercise increases the levels of brain-protecting molecules called neurotrophins. One such molecule is brain-derived neurotrophic factor (BDNF), which acts as a fertilizer for the brain’s cells, helping their connections grow and flourish and protecting them from damaging waste products and toxins (2).

Exercise appears to shield the brain in another way as well. Many are aware of the antioxidants in colorful fruits and vegetables, such as blueberries and spinach. But did you know that our own body has a mighty crew of enzymes that also act as antioxidants? They have complex names, such as superoxide dismutase and catalase, and they act as the cell’s fire department, quenching any free radicals that may accidentally leak during the cell’s operation. If those free radicals are not contained, the excess can cause damage to cells, a state known as oxidative stress. Debilitating conditions such as chronic anxiety and major depression are characterized by chronic oxidative stress in the brain. Numerous studies have shown that aerobic activity, especially high-intensity interval training, can significantly increase the activity of those enzymes (3). You can think of it as your inner fire department getting a powerful upgrade to protect you from oxidative stress and inflammation of the body and mind.

Aerobic exercise and brain health

Aerobic exercise has a powerful effect on the brain, and it provides many of the benefits illustrated above. In one study, a single 35-minute run on a treadmill at 60-70% of the participant’s maximum heart rate (HRmax) improved cognitive performance (4). In another study, individuals that jogged for thirty minutes two to three times a week were better able to sustain attention, plan, and self-regulate (5). These benefits may be partly attributed to changes in the brain’s chemistry following aerobic exercise. A scientific review article from 2017 collected the findings of more than two hundred studies and reported that aerobic activity changes levels of neurotransmitters (e.g., serotonin, GABA, norepinephrine) and neurotrophins (e.g., BDNF, VEGF, IGF-1) (6).

Those pressed for time may be relieved to learn that they might be able to gain some of the brain-boosting benefits of aerobic exercise by performing high-intensity interval training (HIIT) for half the time! One group of researchers reported that even one 15-minute session of HIIT significantly improved memory retention and skill development (7). In another experiment, researchers compared the effects of moderate (70-75% HRmax) and HIIT (90-95% HRmax) on cognition. They found that while both types of exercise resulted in improved cognition, the HIIT group had better information processing speed while the moderate-intensity group had better reaction time (8). While the specific differential effects of moderate and HIIT remain unclear, performing either appears to boost the brain-protecting BDNF significantly. Male study participants who exercised for 20 or 40 minutes at a high or medium intensity saw an increase in BDNF, the only difference being in the magnitude of the spike (9).

Strength training and brain health

Strength training, also referred to as resistance training, includes any exercise that causes the muscles to contract against an external resistance. The goal of this kind of training is usually to increase power and endurance through hypertrophy, the growth of muscle. While most associate this kind of training with weights, this external resistance can be created in various ways, such as using resistance bands or even one’s body weight.

While the effects of strength training on the body have been explored thoroughly, we know little about its impact on brain health. Still, some preliminary findings are promising. It appears that resistance training offers many of the benefits of aerobic activity. For instance, a weightlifting session raises levels of neurotrophins, such as BDNF and IGF-1. These observations may explain why a few studies have found that strength training protects the brain from age-related atrophy and may even help some regions grow. Therefore, when we pump the weights, our brains appear to grow with our muscles! But do these changes in our tissue translate into real-life benefits? Yes, weightlifting individuals seem to perform significantly better in several cognitive tests (working memory capacity, visual processing, problem-solving, etc.) than those who don’t (10).

Strength training, therefore, may be a powerful way to delay the effects of aging on our minds and bodies. After middle age, the average person loses approximately 0.5-1.0% of their muscle mass each year (11). Researchers have also observed that after age 40, the brain loses an average of 5% of its weight per decade, averaging at 0.5% per year. Notice how strikingly similar those numbers are for the loss of muscle and brain tissue. One group of researchers investigated this relationship by following over 300 over ten years and found that greater strength, measured as power in the legs, was strongly associated with an increased brain volume and decreased brain aging at the end of the study. While this does not prove that having strong legs slows aging, it still points to the powerful link between the two. Perhaps this finding may be partly explained if one considers that leg-strengthening compound exercises, such as squats and deadlifts, greatly elevate BDNF, IGF-1, improve immune function, and reduce oxidative stress (10)(12).

Furthermore, resistance training may also have an indirect yet profound impact on our wellbeing. Strength training has been shown to dramatically reduce the risk of injuries, such as sprains, tears, bruises, and fractures. One research article pooled the results of 25 studies and concluded that properly executed resistance training reduced the risk of sports injury to less than a third and the risk of overuse injury by nearly half. This is thought to be because strength training improves joint stability, bone density, and muscle endurance (13). Injuries are common in aerobic activities, especially those with repeated movements, such as jogging and swimming. Therefore, strength training may allow individuals to reap the brain-boosting benefits of aerobic exercise safely and sustainably by dramatically reducing the risk of injury.

The good news is that you don’t need to live in the gym to enjoy the benefits of resistance training. While the frequency and duration of training varied in the studies, most had participants train for an average of 40 minutes (5 minutes warmup, 30 minutes training, 5 minutes cool down) 2-3 times per week. The relatively low frequency is vital to prevent overuse injuries and allow the body to recover between sessions.

The Best Kind of Exercise for Brain Health

While any kind of exercise is better than no exercise, science has revealed that not all activities are made equal in improving brain health. For example, one study pitted martial arts training against walking on a treadmill, comparing their effects on cognitive performance. While both kinds of exercise improved performance, those who practiced martial arts improved their test scores the most (14). In another study, scientists compared the effects of dancing, walking, and nutrition counseling over six months. Those who participated in dancing lessons had an increase in brain tissue, whereas the walking group saw a decline in tissue (15).

But how can some activities have such a different effect on the brain than others? The key to this question may lie in the complexity of the movements performed while exercising. Activities that challenge both the mind and body appear to have a more powerful effect on health and wellness compared to simpler forms of exercise. For example, walking on a treadmill is less challenging to the brain than balancing on a beam because staying on the beam requires many small corrective movements and adjustments to prevent a fall. In contrast, walking on a treadmill consists of a repeating cycle of movements. Complex exercises, such as performing a martial arts routine, appear to challenge a particular part of the brain, the cerebellum.

The cerebellum is a part of the brain that coordinates physical movements and balance. An individual with a damaged cerebellum has difficulty performing complex movements, such as picking up a glass of water (16). It is located at the back of the head, and while it takes up only 1/10th of the brain’s volume, it contains nearly 70% of the brain’s neurons, the cells of the nervous system (17)(18). In the past 20 years, advances in technologies such as neuroimaging have revealed that the cerebellum is intricately connected with brain regions that control higher cognitive functions, such as the prefrontal cortex. Thus, the cerebellum may also be involved in processes such as memory, attention, and emotional regulation. Researchers have suggested that the execution of complex movements challenges the cerebellum, which stimulates other areas of the brain to sharpen focus, regulate mood, and improve memory (19).

Therefore, the best kind of exercise for brain health is any activity that will challenge both the brain and body. For example, 30 minutes of heart-pumping dancing or martial arts practice will have a more powerful effect on activating the brain than intense indoor cycling. But you don’t necessarily have to completely change your exercise routine to gain some of these added benefits. Opting to run on a mountain trail versus a treadmill may elicit a greater cognitive effect. The brain needs to help you avoid puddles and rocks and adjust the muscles activated depending on the shifting incline. 

The same approach of adding complexity to one’s training also applies to resistance training. Calisthenics training, which consists of exercises that rely primarily on a person’s body weight to complete various movements (e.g., pushups, pullups), will challenge one’s balance and coordination much more powerfully than pushing a heavy load on a chest press machine at the gym. By mixing various types of activity, such as bodyweight training, weight training, jogging, and HIIT, you can enjoy the unique benefits of each while keeping your exercise routine fresh and exciting.

In the end, the best kind of exercise is the one you can and want to do. There is no use in picking up an activity that will get you injured in two weeks or that you will dread doing each time. If you are new to exercising, you can start with a simple walk around the block, perhaps with a friend or a favorite audiobook, to make it more fun. If your training regimen is already solid, you can find ways to add complexity to your movements or explore the breadth of activities available, such as rock climbing, martial arts, or interpretive dancing. Both your mind and body will thank you for it!

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References

1. Mandolesi, L., et al. (2018). https://doi.org/10.3389/fpsyg.2018.00509
2. Yang, T., et al. (2020). https://doi.org/10.3389/fncel.2020.00082
3. Azizbeigi, K., et al. (2014). https://doi.org/10.1016/j.jesf.2013.12.001
4. Netz, Y., et al. (2007). https://doi.org/10.1055/s-2006-924027
5. Harada, T., et al. (2004). https://doi.org/10.1016/j.neures.2004.03.011
6. Basso, J. C., & Suzuki, W. A. (2017). https://doi.org/10.3233/BPL-160040
7. Dal Maso, F., et al. (2018).
8. Coetsee, C., & Terblanche, E. (2017). https://doi.org/10.1186/s11556-017-0183-5
9. Schmolesky, M. T., et al. (2013).
10. Herold, F., et al. (2019). https://doi.org/10.1186/s11556-019-0217-2
11. Volpi, E., et al. (2004). https://doi.org/10.1097/01.mco.0000134362.76653.b2
12. Azizbeigi, K., et al. (2014). https://doi.org/10.1016/j.jesf.2013.12.001
13. Lauersen, J. B., et al. (2014). https://doi.org/10.1136/bjsports-2013-092538
14. Douris, P., et al. (2015). https://doi.org/10.1515/hukin-2015-0083
15. Burzynska, A. Z.,et al. (2017). https://doi.org/10.3389/fnagi.2017.00059
16. Bastian A. J. (2011). https://doi.org/10.1016/j.conb.2011.06.007
17. Herculano-Houzel S. (2009). https://doi.org/10.3389/neuro.09.031.2009
18. Wagner, et al (2017). https://doi.org/10.1038/nature21726
19. Schmahmann J. D. (2019). https://doi.org/10.1016/j.neulet.2018.07.005