BDNF (Brain-Derived Neurotrophic Factor)
BDNF is a protein that supports neuron health, survival, and plasticity. Huberman calls it “brain fertilizer”—it’s one of the key molecules explaining why exercise is so good for the brain.
What BDNF Does
| Function | Effect |
|---|---|
| Neuronal survival | Keeps neurons healthy |
| Neuroplasticity | Enables learning and memory |
| Neurogenesis | Supports new neuron formation |
| Synaptic function | Strengthens connections |
| Neuroprotection | Guards against damage |
BDNF is essential for brain health across the lifespan.
BDNF and Exercise
Exercise is the most potent natural BDNF booster:
Acute Effects
- BDNF levels rise during and after exercise
- Peaks shortly after exercise
- Returns to baseline over hours
- Available for plasticity
Chronic Effects
- Baseline BDNF levels increase with regular exercise
- Brain becomes more adaptable
- Cognitive reserve builds
- Protects against age-related decline
What Increases BDNF
| Factor | Effect |
|---|---|
| Cardiovascular exercise | Strongest effect |
| Intermittent fasting | Moderate increase |
| Sunlight | Some evidence |
| Sleep | Required for optimal function |
| Learning new things | Activity-dependent release |
| Social connection | Emerging evidence |
What Decreases BDNF
| Factor | Effect |
|---|---|
| Sedentary lifestyle | Major reduction |
| Chronic stress | Suppresses BDNF |
| Sleep deprivation | Impairs function |
| Depression | Lower baseline levels |
| High sugar diet | May reduce BDNF |
| Chronic inflammation | Negative effect |
BDNF and Memory
The hippocampus (memory center) is rich in BDNF:
- BDNF supports hippocampal function
- Exercise → more BDNF → better memory
- Age-related memory decline linked to BDNF decline
- Exercise may be neuroprotective partly through BDNF
BDNF and Depression
Low BDNF is associated with depression:
- Antidepressants increase BDNF
- Exercise increases BDNF (explains antidepressant effects)
- May explain mood benefits of physical activity
- Supporting BDNF is part of depression treatment
Practical Implications
For Brain Health
Regular cardiovascular exercise:
- Zone 2: 180+ minutes per week
- Higher intensity: additional BDNF boost
- Consistency over intensity for baseline
For Learning
Exercise before or after learning:
- BDNF enhances plasticity window
- May accelerate skill acquisition
- Timing not precisely established but both help
For Mood
Exercise prescription for depression:
- Significant evidence for benefit
- BDNF is part of the mechanism
- At least 150 min/week moderate intensity
Can You Supplement BDNF?
BDNF cannot be supplemented directly:
- Doesn’t cross blood-brain barrier
- Must be produced in the brain
- No pill replaces exercise for BDNF
Focus on behaviors that increase it naturally.
Related Pages
“BDNF is like fertilizer for your brain. Exercise is the most potent way to increase it. This is one of the main reasons exercise is so good for cognition and mood.” — Andrew Huberman