Giving your gray matter a workout is a great idea, but the brain can also benefit hugely from mere physical activity. In her conversation with Sylwia Niemczyk, Dr. Joanna Podgórska, a neurobiologist and science popularizer, explains how physical exercise impacts our memory and thinking.
Dr. Podgórska talks about biology and chemistry in such an engaging and lucid way that thousands of people follow her on Instagram. She promotes a healthy lifestyle, referring not only to her own experience but also to research findings from all over the world. Podgórska gave up her academic career (although that’s not final!) to popularize science. In her recent book Tak działa mózg (How the Brain Works), she argues that we’re not helpless when aging. We can reverse the effects of aging or, even better, prevent them from happening. We simply need to make some effort.
Sylwia Niemczyk: Is it true that juggling is better for the human brain than doing crosswords or sudoku?
Joanna Podgórska: Juggling is wonderful, and I recommend it to everyone. Joking aside, activities that engage both sides of the body are highly recommended from the perspective of neurogenesis and neuroplasticity. Juggling balls is only one example; one can also try writing alternately with the right and left hand or go cycling. It’s true that at some point in my book,
I recommend juggling balls, but I also discuss the importance of intellectual effort. I mean, however, a real effort: what matters is an adequate, relatively high level of difficulty.
Do you mean that, while Przekrój crosswords will work in this context, simple crosswords that take five minutes to complete won’t?
The only beneficial aspect of the latter is killing time. But there is another, very good exercise for the brain: turn the newspaper or a book upside down and try reading it for a few minutes. Activities that require some effort and make us leave our comfort zone of how we usually perceive or understand things have a positive impact on the brain.
The brain defends itself from them, however.
Naturally, we choose comfort, coziness, and familiar things. It has nothing to do with laziness; that’s how our biology and chemistry work. The brain strives to preserve and store energy, which is why our life, to a large extent, is governed by automatisms and habits; doing something that we already know takes less energy than trying something new. Thankfully, we can overcome this, and I encourage everyone to do so, especially if it’s physical activity that constitutes “something new” in our lives. I think it becomes easier for us to try if we know how it will specifically benefit our brains. We should approach physical practice as something rudimental and ingrained in our DNA. Let’s find an enjoyable activity and engage in it regularly. I strongly believe that we should discuss this issue as often as possible, especially in light of our current knowledge about the interdependence of the lack of physical exercise and digestive or neurodegenerative diseases, which include Alzheimer’s.
Let’s further discuss the benefits of physical exercise, then.
Simply setting foot on the ground already initiates cascading benefits. The more dynamic the step, the better. It stimulates blood circulation, sending more oxygen and glucose to the brain. It also improves lymphatic circulation, which allows for the removal of toxins, which, in turn, also impacts brain function. Better oxidation and nutrition then increase the number and efficiency of neurons. During research conducted on mice some time ago, they were unable to use their back feet for twenty-eight days. As a result, the subcortical part of their brains changed significantly—the part responsible for the production of new neural cells. Besides, we can feel that a fast walk clears the head and boosts energy and creative thinking. And if these are the effects of a single walk, imagine what happens if we go for walks more regularly. I guess there is a reason why Aristotle was a peripatetic, and contemporary scholar Daniel Kahneman, professor of psychology and author of Thinking Traps, said, “The best ideas came to me during my dumb walks.”
Other benefits are related to pure chemistry. It turns out that, when the pulse rises during physical exercise, the level of serotonin in the brain increases. And the level of serotonin is correlated with emotional states. Also, endorphins, known as “happy hormones,” are released. For years, the term “runner’s euphoria” was used colloquially. Researchers decided to investigate what was at stake there, and it turned out that people who do intense aerobic exercise—for instance, running or cycling—indeed have an increased level of beta-endorphin, which is extremely important for our mood.
So a person can find happiness by walking or running?
Not everything can be reduced to biology and chemistry. There are also other components, like our personality, experiences, the reality in which we live, and so on. In a nutshell, it can be argued that regular physical activity helps us feel better. When we exercise—and now I will focus on strength training rather than cardio—the level of BDNF neurotrophin rises. It’s a magic protein that enhances communication between neurons and their development, and, in turn, improves logical thinking and memory. It’s not necessary to spend long hours at the gym. It’s better to exercise for a shorter time, but often and regularly. Six- or seven-minute tabata intervals—a series of high-intensity physical training of varied tempo—contribute to the production of a larger amount of BDNF than a 1.5-hour long practice.
It has been determined that the level of BDNF in people with Alzheimer’s disease is lowered, so it can be argued that physical activity can indirectly lower the risk of neurodegenerative diseases. It’s also been confirmed that there is a correlation between a low level of BDNF and depression.
People who have depression sometimes hear such “pearls of wisdom” as “Go for a run or a swim and you’ll get better.”
I would like to be able to say that walking is the best cure for depression, cycling for anxiety, and something else for Alzheimer’s, but it’s simply not true. If a psychiatrist tells a person to take antidepressants, they shouldn’t argue, but start the treatment. The chemical imbalance in the brain needs to be managed first for the person to even have the energy to consider walking. But when a person regains that energy, taking up physical exercise is worth it.
By investigating molecular mechanisms, it can be observed that, when people with depression exercise, new neurons develop, synaptic plasticity and neurotransmitter synthesis improve, and the amount of serotonin and endorphins grows. Physical activity won’t cure serious depression or anxiety disorders, but it can help us go through difficult times. This is an unquestionable fact. In 2022, in the journal JAMA Psychiatry, a comprehensive overview of clinical tests showed that physical activity alleviates the symptoms of depression, anxiety, and distress, which is a destructive kind of stress.
And how can physical activity prevent age-related changes, except by keeping the level of BDNF high?
It’s been established that preventing age-related changes in the brain requires prevention of muscle tissue loss. One reason is that, even in the case of slim people, it tends to be replaced with body fat, which is a reservoir of inflammation. Another reason is that muscle cells contain mitochondria—micro-producers of energy essential for the body and the brain. To grossly oversimplify, muscle mass affects our cognitive abilities. Of course, there is no direct correlation here, but in the body, most things affect each other indirectly. In addition, if one has more muscle tissue and less body fat, they’re more sensitive to insulin, which reduces the risk of type 2 diabetes and insulin resistance. And it’s known today that digestive diseases increase the risk of Alzheimer’s. I need to add, however, that, as in the case of BDNF, it’s not enough to do cardio training like walking or cycling; strength training is also needed.
We said before that it’s beneficial for the brain to initiate changes and try new things. Does this also apply to sports? I’ve been running for half a year, and I’ve turned it into a habit. Should I now switch to cycling?
It’s a good idea to teach the body new movement patterns throughout our entire life: try new postures and realize that we have muscles where we didn’t expect them to be at all. If, however, someone likes only one type of physical activity and doesn’t want to try something else, they don’t need to. By trying new things, I meant traveling, learning languages, getting to know new people, reading books we haven’t read before, or taking a different route from work to home. Let’s always search for something new and exciting since it postpones the brain’s aging, but don’t force anything. I just mentioned the beneficial effects of strength training, and I encourage you to try dumbbell and resistance band exercises. However, if they frustrate you, give them up without feeling guilty. It doesn’t matter if you do sports for ten years, or five years, or two months—pro-brain processes are still taking place in your body: new neural connections are forming, neurons are renewing themselves, and the amount of BDNF is growing.
But perhaps there is some form of exercise that is most beneficial for our brains.
It’s the one that we find the most enjoyable. To keep the brain healthy, any kind of activity is beneficial as long as it doesn’t trigger any strong stress reactions and doesn’t overwhelm us. I like strength training, but I also practice fascia yoga, which doesn’t push the body to its limits. Seemingly, the movements are easy, but after the practice, you can feel your entire body. It’s also like that when I do qigong—a form of gentle exercise originating in ancient China. I can’t explain what happens with my body during the practice per the standards of contemporary science, but I can strongly feel how the energy flows through my body, and I work with it. After practice, my body is a little sore, but pleasantly so, and thoughts are no longer rushing through my brain. I fall asleep easily. Strength training can also be more or less intense. I won’t say which form of activity is superior because, apart from what biology tells us, it’s also important how we feel. It’s important to be good to yourself; physical exercise is a gift we give to ourselves.
You have already emphasized a few times that it’s all supposed to be a pleasure.
That’s precisely when physical exercise makes sense. It’s stress that disrupts our neurochemical balance: it kills us both physically and mentally. Let’s not increase its level by getting exhausted, overworking ourselves, or torturing ourselves with exercise we don’t enjoy only because we “have to lose weight” or “have to build muscles.” In this case, we should talk to a therapist because biochemistry can’t explain everything. According to research published in the scientific journal Cortex in 2021, if we don’t like our body, we lose connection to it; we can’t tell whether it’s hungry or full, whether it’s in pain or pleasure. We can’t tell if we find physical exercise enjoyable and beneficial or stressful and overwhelming. Moreover, if we find a given activity pleasurable, it’s more likely to become a habit. To use the language of biochemistry, a long-term synaptic enhancement will occur. It’s easier for us to learn nice things. So if you don’t like going to the gym, consider dancing. After all, it’s a fantastic exercise, especially for the elderly.
Why?
Because it includes physical, sensory, and social components: a physical one since a person moves using both sides of their body (which is of great importance, as explained before); a sensory component since a person listens to music, adjusts their moves to a varied tempo, and develops a sense of space (which helps to synchronize both hemispheres); and a social one since interactions and conversations with other people to a considerable extent prevent brain degeneration. It’s a perfect combination.
Can dancing actually prevent memory problems?
I’m oversimplifying things, naturally. I like my role as a science popularizer. I consider it important, which is why I didn’t give up laboratory research, but it entails some oversimplifications that I find difficult to accept. My preferred answer to most questions would be “It depends,” because that’s true. I can’t say, “Dance and you won’t get Alzheimer’s.” What I can say is the following: “When you dance and exercise, you do a lot to prevent dementia.” Similarly, it’s not that eating cucumber or kimchi prevents depression. A healthy diet indeed stimulates serotonin production in the intestines, but it’s a slightly different kind of serotonin than the one in the brain. Diet has a colossal impact on health, but it’s not true that “emotions live in the intestines.” They live in the brain, which is, to some extent, affected by the intestines. Physical practice also affects the brain, but nothing is black-and-white here. And it’s great because there is still so much to discover!
To return to science popularization, I’m very glad that, thanks to the Veritas Foundation, I will be able to share with you a film about the impact of physical activity, focusing on its biochemical and psychosomatic aspects and on how it cures the mind. We’re all working on the film pro bono, including the producers from Mojo Movies, whom I befriended on the set. I invited renowned guests to appear in it: psychologist Marta Niedźwiecka explains what physical activity is not about, Tomek Eichelberger discusses qigong and mediation, and Dr. Andrzej Silczuk talks about how sports can help fight addiction on the one hand and become addictive on the other. Such famous people as actors Cezary Pazura or Maciej Stuhr share their experiences connected to physical activity and our mental state, and, most importantly, we talk with many people who regained mental health thanks to exercise. I’m also delighted that Jerzy Górski, a triathlete and protagonist of the movie Najlepszy (Breaking the Limits), who overcame the horrible demons of addiction thanks to sports, also agreed to take part in it. Currently, he is teaching “animal flow”—a physical exercise during which one imitates the movements of animals. Yet another activity that might suit us.
Is it sometimes the case that, when you encourage your readers to be active, they say that they are too active in their daily lives?
I also strongly encourage them to relax. Physical exercise always needs to go in tandem with recovery. Unfortunately, it seems to me that we approach this issue in a very irresponsible way. As neuroimaging shows, during sleep and relaxation, the hippocampus rebuilds itself, the number of neurons and neural connections increases, and the amount of white matter, axons, and myelin increases, which is of fundamental significance for the effective transmission of neural signals in the brain. The number of neurotransmitters—such as acetylcholine and dopamine—also grows, and they’re of key importance for the workings of memory. Physical activity and rest have a lot in common. And it’s not only that they both prevent the brain from aging or are both pleasurable and beneficial. They are both within our reach, and we can all make use of their positive effects.
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