How Exercise Shapes Brain Health: Q&A with Kirk Erickson
When we talk about exercise, most people think of weight loss, heart health, or building muscle, but what if one of its most powerful effects happens in your brain?
Dr. Kirk Erickson has spent the last two decades answering that question. A leading researcher in the field of brain health and physical activity, Dr. Erickson is the Director of Translational Neuroscience and Mardian J. Blair Endowed Chair of Neuroscience at AdventHealth. He’s published more than 250 papers, chaired the Brain Health subcommittee for the U.S. Physical Activity Guidelines, and helped design major clinical trials on the impact of movement on cognition and aging.
In this interview, we discuss misconceptions, minimum effective doses, and why it’s never too late to start moving for your mind. Whether you’re an athlete, therapist, parent, or just trying to stay sharp as you age, there’s gold in this one.
Let’s dive in.
5 Questions with Kirk Erickson
1. What common misconceptions do people have about the relationship between physical movement and brain health?
The first misconception is the idea that someone needs to engage in vigorous intensity activity and become nearly an athlete to show effects on brain/cognition. In contrast, we often see some of the greatest benefits from moderate intensity exercise in people who are really deconditioned at the start. Another common misconception is that this is simply driven by cardiovascular effects (e.g., increased blood flow to the brain). In contrast, exercise affects many different pathways, so it’s likely that a combination of physiological changes drive the effects. For example, if exercise decreases inflammation, affects glucose regulation, up-regulates gene transcription of neurotransmitters or neurotrophins, etc. then it might be these pathways independently of any changes in cardiovascular health that could be the drivers of brain health improvements.
2. Can you elaborate on the link between physical health, cognitive function, and mental well-being? How are these systems interconnected?
Great question. These are very interconnected concepts. Cognitive function and mental health are emergent properties of brain function and the brain itself is affected by many different peripheral physiological states. Of course the brain reads signals from the periphery and then feeds back information to the body to tell it what to do – e.g., run from a predator. If the body’s signals to the brain are being affected by other physiological challenges – e.g., diseases, obesity, muscle loss, then these factors will influence the brain like any other physiological signal. In turn, any physical or physiological state (e.g., obesity) that affects the brain has the potential of disrupting the emergent properties of brain function including mood and cognition. But, we also have to remember that the brain is not just a passive receptacle of things happening to or in the body. Our brain helps to control peripheral physiology and function and decisions of the brain (e.g., eat the donut instead of the apple) will affect peripheral physiology. It is these interconnecting systems that make the evaluation and analysis so complex and so important.
3. For someone seeking the minimum effective dose of exercise to boost cognitive and mental well-being, what would you recommend in terms of frequency, duration, and intensity? Is there a particular type of exercise that’s especially effective?
Both resistance and aerobic activities have been shown to positively affect brain, cognition, and mental health. Usually targeting the current physical activity guidelines is a good model – e.g., at least 150 minutes per week of moderate-intensity exercise. We know less about frequency, bouts, etc. so I would for now encourage people to achieve the 150 minutes per week as the target and if that comes over 2 days or all 7 days, there will likely still be benefits (although there is much more work to do in this space).
4. For someone who has been sedentary for much of their life, is there still potential for significant improvements in brain health through exercise, or is it too late to start? What would you recommend for someone just beginning to incorporate movement into their routine?
We’ve learned that it is never too late to start exercising! We enroll people into our studies that are highly inactive and report being inactive most of their lives and we still see benefits from engaging in the exercise intervention (in fact these people might show a greater magnitude of benefits). That being said, there does seem to be better long-term risk reduction if the person has been exercising for a longer period of time and we know that habit formation takes some time and is better to be implemented and started earlier in life. If someone is looking to become more active they should (a) do things that they enjoy and don’t force themselves to do things that are not enjoyable, and (b) progress exercise in small steps. That is, don’t expect that you’ll become really fit over night. It takes time and patience. Be aware of your body and work on pushing yourself.
5. How does exercise compare to other lifestyle factors, like nutrition or sleep, in its impact on brain health? Is there a synergy between these factors that people should be aware of?
There is certainly synergy and we are still trying to learn how this works and the combined impact of these behaviors on brain health. Poor sleep is a risk for dementia, but we know that physical activity tends to improve some aspects of sleep. Sleep deficits on cognition might also be offset by participating in exercise. Similarly, nutrition is critically important and might also interact with exercise behaviors. It’s likely that benefits of a healthy diet on brain health is augmented in people who are also physically active. But, we still have a lot to learn about the effects of these combinations on various brain health metrics.
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