What if getting smarter had less to do with puzzles and brain games — and more to do with how you sleep, move, and eat? According to neuroscientist Dr. Tommy Wood, that's exactly the case.
In a conversation on Reason & Wellbeing, Dr. Wood — a researcher at the University of Washington — laid out the evidence for what actually improves brain function. And most of it has nothing to do with what the "brain optimization" industry is selling.
Your brain is not a muscle (but it responds like one)
The brain-as-muscle metaphor is everywhere. "Train your brain." "Mental gains." But Dr. Wood explains that the brain doesn't improve from isolated cognitive exercises the way a bicep grows from curls. Brain games make you better at brain games. That's about it.
What actually changes your brain's structure and function? The same things that change the rest of your body: physical exercise, quality sleep, proper nutrition, and managing stress. The brain is an organ, and it responds to whole-body signals.
Exercise is the most powerful cognitive enhancer we have
If you could bottle the cognitive effects of exercise, it would be the most prescribed drug in the world. Dr. Wood is emphatic on this point: regular physical activity is the single most effective intervention for brain health.
Here's what happens when you exercise consistently:
- BDNF production increases — brain-derived neurotrophic factor, often called "miracle-gro for neurons," supports the growth of new brain cells and strengthens connections between existing ones
- Cerebral blood flow improves — more oxygen and nutrients reach brain tissue
- Inflammation decreases — chronic low-grade inflammation is one of the biggest threats to long-term brain function
- Insulin sensitivity improves — the brain is highly sensitive to insulin signaling, and insulin resistance is increasingly linked to cognitive decline
The type of exercise matters less than consistency. But combining resistance training with cardiovascular work appears to provide the broadest cognitive benefits. You don't need to train like an athlete. You need to train regularly.
Sleep is when your brain cleans house
During sleep, your brain activates the glymphatic system — a waste-clearance pathway that flushes out metabolic debris, including amyloid beta, a protein linked to Alzheimer's disease. This system is most active during deep sleep.
When you cut sleep short or fragment it, this cleanup process is interrupted. Waste accumulates. Over months and years, this may accelerate cognitive decline.
Dr. Wood stresses that sleep quality matters more than sleep quantity for brain health. Seven hours of deep, unbroken sleep serves your brain better than nine hours of restless tossing.
What you eat feeds your brain — literally
Your brain accounts for roughly 2% of your body weight but consumes about 20% of your daily energy. It's metabolically expensive, and it's picky about fuel.
The nutrients that matter most for brain function, according to Dr. Wood:
- Omega-3 fatty acids (DHA) — structural components of brain cell membranes. Low levels correlate with accelerated brain aging
- Creatine — not just for muscles. The brain uses creatine as an energy buffer, especially under stress. Supplementation supports cognitive function during sleep deprivation and high mental demand
- B vitamins and choline — essential for neurotransmitter production and methylation
- Antioxidants that actually reach the brain — compounds like ergothioneine (which has a dedicated transporter) and lutein (which accumulates in brain tissue) are more relevant than generic antioxidant supplements
"The brain is an incredibly demanding organ. It needs the right raw materials, consistent energy, and regular maintenance through sleep. There are no shortcuts — but the fundamentals are remarkably powerful."
— Dr. Tommy Wood, neuroscientist, University of Washington
Stress is the silent brain killer
Chronic stress physically shrinks the hippocampus — the brain region responsible for memory and learning. Cortisol, the primary stress hormone, is toxic to neurons at sustained high levels.
Dr. Wood notes that occasional acute stress is normal and even beneficial. The problem is chronic, unresolved stress — the kind that comes from poor sleep, overwork, and never fully recovering.
The most effective stress management interventions are also the simplest: regular exercise, adequate sleep, time in nature, and meaningful social connection. These aren't soft recommendations. They're neurobiological necessities.
The compound effect
What makes Dr. Wood's perspective so compelling is how all of these factors reinforce each other. Exercise improves sleep. Better sleep reduces stress. Lower stress improves food choices. Better nutrition supports exercise recovery. It's a virtuous cycle.
Conversely, neglect one and the others start to degrade. Skip sleep, and your stress hormones rise. Stress increases inflammation. Inflammation impairs exercise recovery. You eat worse. The cycle reverses.
Getting smarter isn't about finding one hack. It's about maintaining the system.
Frequently asked questions
Do brain training apps actually work?
They make you better at the specific tasks in the app, but evidence for broad cognitive transfer is weak. Physical exercise has far stronger evidence for general cognitive improvement than any brain game.
What's the single best thing I can do for my brain?
Exercise consistently. The combination of cardiovascular and resistance training provides the broadest cognitive benefits, from increased BDNF production to improved cerebral blood flow and reduced inflammation.
Does creatine really help brain function?
Yes — particularly under stress. The brain uses creatine as an energy buffer. Research shows supplementation supports cognitive function during sleep deprivation, hypoxia, and high mental demand. It's especially beneficial for older adults and those who eat less meat.
At what age does cognitive decline start?
Some cognitive functions begin declining as early as your late 20s, but the rate of decline is heavily influenced by lifestyle factors. The interventions discussed here — exercise, sleep, nutrition, stress management — can substantially slow age-related cognitive changes.
This article draws on research discussed by Dr. Tommy Wood on Reason & Wellbeing, Greg Potter's science-focused interview series. Dr. Wood is a neuroscientist and researcher at the University of Washington.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
