The Trigger — Amygdala Activation
A real or misread bodily sensation is flagged as dangerous by the brain.
- <100 ms: Amygdala response time (faster than conscious thought)
- ~11%: Lifetime panic attack rate (of adults, at least once)
- Real or false: Trigger type (alarm both feel identical)
- Adrenaline: Stress hormone released (from adrenal medulla)
Amygdala fires the alarm
Sensory input reaches the amygdala before the cortex can reason about it.
False alarms feel identical
A racing heart from coffee can be misread as mortal danger.
Placeholder: the alarm itself does not distinguish real from misread threat.
Fight-or-Flight Cascade
Adrenaline spikes heart rate, breathing rate, and muscle blood flow rapidly.
- +30–50 bpm: Heart rate rise (within seconds)
- 2–3×: Breathing rate rise (normal resting rate)
- Muscles: Blood flow shift (away from digestion)
- Seconds: Onset speed (to full activation)
Adrenaline floods the body
Heart and lungs both accelerate to prepare for action.
Breathing overshoots need
Rate rises faster than the body actually requires oxygen.
Placeholder: this overshoot is what starts hyperventilation.
Hyperventilation Causes Hypocapnia
Fast breathing exhales CO2 faster than the body produces it.
- ~40 mmHg: Normal blood CO2 (arterial partial pressure)
- <35 mmHg: Hypocapnia threshold (onset of symptoms)
- ~15–20 mmHg: Severe hyperventilation CO2 (during panic episode)
- ~1–2 min: CO2 drop time (of fast breathing)
CO2 falls, pH rises
Excess exhalation drops CO2 and shifts blood pH upward.
Oxygen was never the problem
Blood oxygen stays normal — CO2 is the driver here.
Placeholder: hypocapnia, not low oxygen, drives panic symptoms.
Cerebral Vasoconstriction & Sensation
Low CO2 narrows brain blood vessels, producing dizziness and tingling.
- ~2%/mmHg CO2: Cerebral blood flow drop (per mmHg below normal)
- Dizzy, tingling: Common symptoms (lightheaded, breathless feeling)
- Feels like suffocating: Paradox (despite normal oxygen)
- ~1–3 min: Symptom onset (into hyperventilation)
Vessels narrow, brain protests
Reduced blood flow to the brain triggers dizziness signals.
Breathlessness despite oxygen
The choking sensation is a CO2 effect, not oxygen lack.
Placeholder: this paradox is the physiological core of panic.
Vicious Cycle — and Breaking It
Frightening sensations are misread as danger, amplifying the fight-or-flight loop.
- 5: Feedback loop nodes (trigger to amplified fear)
- ~10 min: Typical attack duration (peak intensity)
- ~6 br/min: Retraining target rate (slow diaphragmatic breathing)
- ~2–3 min: CO2 recovery time (with slow breathing)
Symptoms are misread as danger
Dizziness confirms the alarm, which drives faster breathing still.
Slow breathing breaks the loop
Diaphragmatic breathing restores CO2 and quiets the alarm.
Placeholder: breathing retraining interrupts the loop at its weakest link.