Movement
BDNF — your brain's growth factor — increases significantly during exercise. One of the most well-supported interventions for cognitive health.
If you only do one thing from this chapter:
Walk 20 minutes after your largest meal
That's it. Post-meal walking blunts the glucose spike that causes afternoon fog. No gym membership, no equipment, no willpower required.
Too foggy to read this section? Start here:
- • Walk 20 minutes after your largest meal — this alone improves post-meal fog
- • Do 30 min moderate cardio 3×/week for the BDNF surge (brain growth factor)
- • Exercise outdoors when possible — 2× neurotrophin response vs. indoors
Dual-Tasking: Combine Walking with Cognitive Challenge
While walking, try naming animals alphabetically, counting backward from 100 by 7s, or listing months in reverse. This forces your brain to allocate resources to both motor and cognitive networks simultaneously — a form of training that targets executive function more effectively than either walking or brain games alone.
Why Movement Works
BDNF Release
Brain-derived neurotrophic factor increases by 200-300% after aerobic exercise. BDNF = brain fertilizer.
Blood Flow
Cerebral perfusion increases immediately. More oxygen, more glucose, less fog.
Inflammation ↓
Regular exercise reduces systemic inflammation markers within 2-4 weeks.
Sleep Quality ↑
Exercise improves deep sleep architecture. Just don't do it within 3 hours of bed.
Post-Exertional Malaise Warning
If you have ME/CFS, Long COVID, or POTS, exercise can make you worse. The standard advice "just exercise more" is dangerous for these conditions.
Start with heart-rate-limited pacing (stay below your anaerobic threshold, typically 60-70% max HR). If you crash after exercise, reduce intensity dramatically and consult a specialist.
→ See Long COVID pacing protocolsExercise by Condition
Standard Brain Fog
Zone 2 cardio (can hold conversation) 30-45 min, 3-5x/week
ME/CFS / Long COVID
Heart-rate limited (HR <110 or your personal threshold). Start with 5 min walks.
POTS / Dysautonomia
Recumbent exercises first (rowing, swimming, recumbent bike). Upright tolerance improves over time.
Movement Strategies (6)
Zone 2 Cardio
1 year of aerobic exercise increased hippocampal volume by 2%, reversing 1-2 years of age-related loss. The hippocampus — your memory center — physically grows with aerobic exercise.
PROTOCOL
150 min/week at conversational pace (can talk, can't sing). Walk, bike, swim, dance. 30 min × 5 days or 50 min × 3 days.
Resistance Training
2025 network meta-analysis: strength training improves cognition independently of cardio. Releases myokines (muscle-derived growth factors) that cross the blood-brain barrier.
PROTOCOL
2-3 sessions/week. Full body compound movements: squat, hinge, push, pull. Progressive overload. Can be bodyweight, bands, or weights.
Cognitive Pacing (ME/CFS)
For post-viral fatigue: stop BEFORE exhaustion hits. Activity envelopes prevent crashes. Post-exertional malaise (PEM) can delay symptoms 24-72 hours.
PROTOCOL
Heart rate monitor: stay below aerobic threshold (often 60-70% max HR). Activity diary. Plan rest before activity. 3-day delay effect.
⚠️ Essential for ME/CFS and Long COVID. Graded Exercise Therapy (GET) is contraindicated.
Water-Based Activity
Buoyancy reduces mechanical load. Hydrostatic pressure improves venous return. Ideal for POTS, chronic pain, and exercise intolerance.
PROTOCOL
Swimming, water aerobics, or pool walking. 20-30 min, 2-3×/week. Water temperature 82-86°F for chronic fatigue.
Movement Snacks
Prolonged sitting impairs cerebral blood flow. Brief movement breaks restore perfusion. 2-3 minutes every 30-60 minutes of sitting.
PROTOCOL
Set timer every 30-60 min. Options: stairs, squats, jumping jacks, walk to water fountain. Minimum: stand and stretch.
Nature Exposure
20 minutes in a natural environment reduces cortisol by 20%. Forest bathing (shinrin-yoku) reduces inflammatory markers and improves mood.
PROTOCOL
20+ min in green space (park, forest, garden). Phone off. Walk slowly. Engage senses: birdsong, leaves, fresh air.
200–300%
BDNF surge during moderate aerobic exercise
Brain-Derived Neurotrophic Factor — your brain's growth hormone — surges during moderate aerobic exercise. This is the most potent neurogenesis trigger known.
PART III
Supplements
Creatine, Lion's Mane, and evidence-tiered nootropics
PART V
Autonomic Balance
HRV training and vagal tone protocols
This information is for educational purposes only. Always consult with a qualified healthcare professional.