The effects of mild to moderate aerobic exercise on the human mind differ from those of high-intensity exercises over a complete calendar year, according to a recent study from Dartmouth College. This groundbreaking study reveals that regularly engaging in cardio (such as walking, jogging, or swimming) at either an easy or difficult speed has an impact on the mind in several ways. These findings were released on August 15 in the peer-reviewed journal Scientific Reports (Manning et al., 2022).
Fitbits were utilized by the first author, Jeremy Manning, and colleagues to gather data on actual activity intensity from 113 participants over a year. The purpose of the study was to evaluate the researchers’ claim that “differing physical exercise intensities had differing quantitative impacts on cognitive performance and mental wellness.”
Exercise Intensity on the Mind of an Ultramarathoner: Road-Tested Effects
I’m going to offer some anecdotal insights and tried-and-true methods that I intentionally vary the intensity of my cardio exercises to improve how my mind functions depending on each day’s cognitive demands before digging into these evidence-based research findings.
As an ultra-endurance runner who set a Guinness World Record in 2004 by completing six back-to-back marathons on a treadmill, I’ve devoted a lot of time to analyze how different exercise intensities impact my mental clarity and well-being. Based on the dose-response of mild, moderate, or strong aerobic exercise, I’ve learned how to adapt my daily exercises to help me think better and feel less worried or unhappy.
I’ve been interested in how exercise impacts the mind for a long time. My father, a neuroscientist, studied the effects of physical activity on sheep’s brains in the 1970s by placing the animals on a treadmill and tracking the results. Dad took a six-month leave of absence from his position as a neurosurgeon at Harvard Medical School to study living sheep housed at the Florey Institute in Melbourne, Australia, to undertake in vivo research on how exercise affects the mammalian brain.
Dad conducted brain research on exercise at a time when jogging was popular across the country and people began to link the so-called “runner’s high” to the production of endorphins, which were identified and given names in the mid-1970s (Pert & Solomon, 1973).
At the time, runners were fervent in Boston, where my family was based, and no amount of snow, sleet, or rain could deter them from obtaining their daily “exercise fix.” My father was interested in researching the biology behind runners finding “joy” in vigorous exercise, which is normally seen as “painful,” based on Thorndike’s Law of Effect (“all creatures seek pleasure and avoid pain”).
Sadly, my father’s animal studies on the potential impact of exercise on the electrical environment of the mammalian brain ultimately produced no significant findings. His unsolved research issues nevertheless motivated me to continue seeking empirical data that adds to our understanding of how aerobic exercise can affect how the mind functions and to draw lessons from my own experience.
I turned myself into a human test subject when I began jogging frequently as a teenager in the summer of 1983. I would mentally note how a strenuous workout changed the way my mind functioned before and after every run, and I would share these anecdotal discoveries with my father. He was working on the manuscript for his 1986 book The Fabric of Mind at the time.
Beyond the “runner’s high” and feeling better after a hard workout, it became clear that running practically every day throughout my final year of high school had improved my ability to think when I entered college in the fall of 1984.
I avoided strenuous activity throughout most of the high school, and it felt that my brain had difficulties remembering things. Academically, I had difficulty. Before the summer of 1983, when I started including jogging in my daily routine, I was a straight C- student with subpar SAT scores.
But after a year of jogging most days of the week at a moderate-to-vigorous pace, my brain changed; my memory was sharper, and I found learning to be simpler. It was evident from my personal experience that a year of consistent aerobic exercise at a moderate to high intensity had improved my cognitive function.
Three Ways Changing Aerobic Intensity May Change How the Mind Functions
1-Easy “Yellow” Zone, Light Intensity: encourages daydreaming and wandering thoughts; this stress-relieving tempo is calming and reduces tension.
2-Moderate Intensity (“Orange” Flow Channel): This is the optimal intensity for experiencing flow states and having “Eureka, I’ve discovered it!” moments during a cardio workout. It facilitates problem-solving and connecting the dots between concepts that appear to be unrelated.
3-High Intensity (Vigorous “Red” Zone): One to three hours after a “red zone” HIIT activity is over, cognitive benefits including verbal fluency and quicker recall are felt. Workouts at a high level are beneficial 60 to 90 minutes before an exam or interview.
My observations (mentioned above) that exercising cardio at varying color-coded aerobic intensities—easy (yellow), moderate (orange), and hard (red)—affects how the mind functions in predictable dose-responsive ways were not well supported by evidence-based studies until recently.
To the best of my knowledge, the most recent (2022) study from Dartmouth College is the first of its kind to shed light on how particular exercise intensities might be recommended to assist students who are having trouble in the classroom or who are dealing with mental health issues based on the dose-response of light-, moderate-, or high-intensity cardio sessions.
Be patient because it takes time for exercise to improve our cognitive abilities.
Most research on the relationship between exercise and cognitive processes hasn’t examined the long-term effects of different aerobic intensities on cognition over a full year.
According to the authors, “most primary research approach physical activity as a binary variable that is either present or absent for each participant.” “The majority of earlier studies likewise monitor or alter activity over very brief periods (typically on the order of days or weeks). “The true relationship” between physical exercise, cognitive function, and mental health, according to the researchers, “unfolds over significantly longer durations than have previously been documented.”
Overall, Manning et al. discovered during this 12-month trial that maintaining physical activity (of any intensity) enhanced cognitive function and benefited mental health. But different levels of exercise appear to have distinct effects on memory. For instance, the researchers discovered that those who regularly engaged in low-to-moderate intensity exercise tended to score better on tasks requiring episodic memory. On the other hand, those who exercised vigorously performed better on tests of spatial memory.
“We discovered that there are numerous connections between fitness-related activities, memory function, and mental wellness. Participants who frequently engaged in a certain level of physical activity, for instance, also frequently performed better on specific memory tasks than others “the authors pen words. This implies that not all areas of cognitive or mental health will necessarily be impacted equally (or in the same direction) by engaging in a certain type or level of physical activity.
People who didn’t consistently engage in high-intensity exercise tended to be less stressed out and experience lower rates of anxiety. The researchers stress that these findings are correlated nevertheless. It is impossible to determine whether exercising at a slow to moderate pace made study participants feel less stressed or if individuals who typically experienced lower levels of stress in their daily lives, regardless of their exercise habits, tended to exercise more slowly.
Manning stated in a September 2022 news release that “there is a pretty sophisticated dynamic at play when it comes to physical exercise, memory, and mental health that cannot be summed in single statements like “Walking improves your memory” or “Stress harms your memory.” Instead, certain types of exercise and certain mental health conditions appear to have a varied impact on each facet of memory.
This Dartmouth team will continue to investigate the best methods for adjusting exercise intervention intensity to suit each person’s particular demands. As Manning notes, particular exercise-intensity programs may be created to aid students in studying for tests, enhance mental health in general, and boost various sorts of cognitive functions.