This is the third in a series of five articles, each one expanding on a principle from Five Practices for a Life Aligned with Nature, where I laid out the five roots of my Purely Rooted philosophy. This article goes deeper on the third: Move Your Body Every Day.
Humans are the greatest endurance animals on the planet. Before we invented spears, we ran prey to exhaustion over hours and miles, a hunting strategy called persistence hunting that relied on our ability to sweat, breathe, and cool ourselves while running in the midday heat. Our Achilles tendons, our arched feet, our massive gluteal muscles, our ability to stabilize our heads while running: all of these are evolutionary adaptations for sustained movement. We didn’t evolve to sit in chairs for eight hours a day. We evolved to move, and our biology still expects it.
In that original article, I mentioned that exercise is 1.5 times more effective than medication for depression and anxiety. But this piece isn’t about exercise in the gym-membership, fitness-tracker sense. It’s about something more basic: what happens to the human body and brain when movement stops.
Movement Grows New Brain Cells
Your brain produces a protein called brain-derived neurotrophic factor (BDNF) that acts like fertilizer for neurons. BDNF supports the survival of existing neurons, promotes the growth of new ones (a process called neurogenesis), and strengthens the connections between them (synaptogenesis). Low BDNF levels are consistently found in patients with depression, anxiety disorders, Alzheimer’s, and Parkinson’s.
Physical movement is the most reliable way to increase BDNF. Aerobic exercise increases BDNF levels in the hippocampus, the brain region most responsible for memory, learning, and emotional regulation. A 2025 review in a neuroscience journal confirmed that exercise-induced BDNF release improves emotional regulation, alleviates symptoms of depression and anxiety, and supports cognitive functions including memory and attention. The effect is dose-dependent: moderate-intensity aerobic exercise (60-70% of max heart rate) performed for 30-40 minutes, three to four times per week, produces the strongest BDNF response.
Put plainly: movement literally grows new brain cells. Sitting does not. And no pill on the market replicates this effect.
The Cost of Sitting Still
The average American adult sits for 6.5 to 8 hours per day. Office workers often exceed 10. And the health consequences scale with every additional hour.
A meta-analysis published in PLOS ONE, drawing on data from 595,086 adults and 29,162 deaths, found that sitting for 10 hours per day was associated with a 34% higher risk of all-cause mortality compared to sitting for one hour per day. A 2024 JAMA Network Open study confirmed the dose-response: each additional hour of daily sitting increased mortality risk by roughly 3%, even after accounting for leisure-time physical activity.
There is good news buried in the data, though. A Lancet meta-analysis of over one million people found that 60 to 75 minutes of moderate-intensity physical activity per day effectively eliminated the increased mortality risk associated with prolonged sitting. You can’t undo sitting with a weekend jog, but consistent daily movement does appear to neutralize its worst effects.
Movement, Not Exercise
Here’s where I think most health advice gets it wrong. The conversation always centers on “exercise,” which implies a scheduled, structured activity you do for a set period and then stop. But our ancestors didn’t exercise. They moved. All day. Walking, carrying, squatting, climbing, bending, lifting. Movement wasn’t separate from life; it was life.
The modern concept of exercise was invented to compensate for a modern problem: the sudden, radical elimination of movement from daily life. We sit to commute, sit to work, sit to eat, sit to relax. Then we schedule 45 minutes of movement and call it a workout, as if that brief window can offset the other 15 waking hours of stillness.
A better frame is to think of movement like breathing: continuous, varied, and woven into everything you do. Walk to the store instead of driving. Stand while you take phone calls. Squat to pick things up instead of bending at the waist. Carry your bags. Take the stairs. Stretch while you wait for the kettle. Park at the far end of the lot. These small choices add up to hours of accumulated movement each week, and they don’t require a gym membership, a sports bra, or a recovery shake.
Start With What You Have
If you’ve been sedentary for years, the idea of 60-75 minutes of daily activity can feel overwhelming. So don’t start there. Start with a 10-minute walk after dinner. Do that for a week. Then add a morning stretch. Then walk a little faster, a little longer. The research on BDNF and neurogenesis says your brain begins changing within the first few weeks. You’ll feel it before you see it: better sleep, clearer thinking, a mood that lifts for no obvious reason.
Your body was built for this. Every joint, every muscle, every tendon in your frame was shaped by millions of years of constant motion. Sitting for most of the day and then wondering why you feel stiff, foggy, and anxious is like keeping a border collie in a studio apartment and wondering why it chews the furniture. The design demands the use. Honor it.
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