We talk a lot about the developing brain on this podcast. The importance of early childhood, what kids need, how environment shapes them, etc. But there’s another brain in the room that we don’t talk about nearly as much, and it belongs to the parent who’s running on four hours of sleep, eating standing over the kitchen counter, and stress-managing everything from homework meltdowns to the family calendar.
This week, I talked with Dr. Majid Fotuhi, neurologist, neuroscientist, and bestselling author of The Invincible Brain about what’s actually happening to the adult brain, and what we can do about it. He’s spent 40 years studying neuroplasticity: the brain’s capacity to change, rewire, and yes, actually grow at any age.
Our brain is not a fixed structure like your ears. It is a dynamic structure that is constantly changing. - Dr. Majid Fotuhi
Dr. Fotuhi explains that the brain changes every day at a microscopic level. And depending on what you do, it either grows slightly or shrinks slightly. Do the same things consistently over years, and those changes become measurable. This means the narrative that so many of us have quietly absorbed — that at some point in adulthood the brain just starts to go — isn’t quite right. It’s more that our daily choices accumulate, in either direction.
The five things that matter most
Dr. Fotuhi talks about five pillars of brain health: exercise, sleep, nutrition, stress reduction, and brain training. The brain needs daily maintenance, and most of us aren’t giving it that.
Exercise. Walking 5,000 steps a day is enough. You don’t need a gym or a structured workout to make a meaningful impact on your brain. Most parents are already fairly active just from the physical demands of daily life, but the goal is consistency more than intensity. Studies have shown that regular aerobic exercise measurably increases hippocampal volume.
Sleep. During deep sleep, the brain runs its own cleaning process. The glymphatic system clears out waste and metabolic byproducts. When you sleep fewer than six hours consistently, that system doesn’t run properly, and those waste products accumulate. Over time, this shrinks the brain. Twenty to thirty years of poor sleep can reduce hippocampal volume by close to half, with measurable effects on memory. The good news is that the brain can recover. Studies of patients who treated sleep apnea showed hippocampal regrowth after treatment. The brain, as Dr. Fotuhi put it, has a repair kit that’s always on standby. The goal is to stop overriding it. He recommends a dark, quiet bedroom used for sleeping, reading, and nothing else; no caffeine in the afternoon; and, if you’re transitioning from years of poor sleep, magnesium gluconate can help.
Nutrition. The research here is most clearly about what to avoid. Junk food (i.e. fast food, sugary drinks, refined snacks) has a direct, dose-dependent relationship with brain shrinkage. The bigger the belly, the smaller the hippocampus. Dr. Fotuhi compared regular junk food consumption to smoking: the harm is real and cumulative, even if it doesn’t feel that way in the moment. His recommendation isn’t a restrictive diet, but something sustainable where an occasional indulgence is fine.
Stress. Cortisol, the stress hormone, has a direct relationship with hippocampal shrinkage, shown clearly in a Japanese study that tracked people’s cortisol levels and brain size over seven years with no other intervention. Those who sustained higher cortisol levels over that period had smaller hippocampi by the end. Dr. Fotuhi explains that chronic stress over small things like traffic, imperfection, or minor inconveniences, tax the brain the same way that significant stressors do. Reserving your stress response for things that actually warrant it is, it turns out, a concrete brain health strategy. Healthy relationships, joy, and a sense of meaning fall under this pillar too. These aren’t soft additions. They’re part of what keeps the brain in a state where it can maintain and repair itself.
Brain training. Anything that’s a little difficult for you counts. Mahjong (my personal obsession), a new language, photography, sudoku, crossword puzzles, reading with real attention. If something is so familiar and easy that you’re not really engaged, it’s not doing much. If you’re frustrated, focused, or thinking hard, you’re training your brain. The discomfort is the point.
The story you repeat to yourself about your own brain shapes what your brain actually does. “I’m not good with names” is a perfect example: you say it, so when you meet someone new, you don’t really try, and then you don’t remember them, and then you say it again. A self-fulfilling prophecy, literally reinforced in the brain. The reverse works the same way. Telling yourself you’re good at remembering names brings effort to look someone in the eye, use their name in conversation, form some association, and produce the opposite result. The narrative determines the effort, and the effort determines the outcome. If your internal story is that aging means cognitive decline, decline becomes more likely. If it’s that some things slow down but you’re still fully capable of learning, engaging, and contributing, that’s also what tends to happen. There’s actual data on this. Your view of your own aging predicts brain outcomes.
What this means for your kids
What you model matters more than what you instruct. A calm home, consistent sleep, real food, ways to be challenged and frustrated, and time to figure things out on your own. These things are literally shaping your children’s brains. And the same things that protect your brain protect theirs. Start small and let the changes become habits. Consistency over time is what matters, not an intense short burst.
And start telling yourself a better story about your own brain. Because the brain is more forgiving, more responsive, and more capable of change than most of us give it credit for. Check out the latest episode of Raising Good Humans Podcast for more.
This episode is sponsored by Ooma. Fun for kids, peace of mind for parents. MyPhone by Ooma gives kids safe calling with parental controls—no apps, no scrolling, just connection.
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