Carbon Dioxide is the metabolic stress messenger of the human body. Your body is constantly predicting how much energy you need to deal with stress and how much more stress you can take! Get ahead of the curve with this powerful metric for stress and resilience.
The CO2 Tolerance Test is a gateway to understanding how you respond to stress. Originally used by freedivers and developed through extensive trials and applications, including in conjunction with Stanford University’s Huberman Lab this test has been proven to be a powerful indicator of stress response, autonomic control, and breath mechanics.
Carbon Dioxide (CO2) tolerance is important because:
- CO2 is the signal to your brain to breathe (not oxygen)
- This signal is fired in response to your metabolic needs of each moment, exercise, and stress in general; including your perception of stress!
- The interpretation of this signal can go haywire from poor health, trauma, and dysfunctional breathing habits. This can make the system more sensitive and less tolerant of rising CO2 levels.
- Connecting the increase of tolerance and decrease of sensitivity over time can give great insight into how your body deals with stress and can lead to a better resolution of behavior that causes maladaptation.
- Follow the directions below to find your current CO2 Tolerance. Then you can use your time to calculate personalized Apnea and Cadence Breathing Protocols. Retest every 2-3 weeks to measure your progress and calibrate your personal protocol to what works for you and how you're feeling.
Directions for Test:
Get a stopwatch
All breaths are through your nose only
Take 3 normal nasal breaths
Take 1 more full nasal inhale and fill your lungs all the way
Start to nasal exhale, start your timer
Exhale through your nose as slowly as you possibly can, for as long as you can
DON'T hold your breath or swallow. If that happens, stop your timer
When you have no air left to exhale, stop your timer
Record your time and input it below in the Apnea and Cadence Calculators to obtain personalized breathing protocols
What does your test result mean?
>80 seconds --> Elite. Reflects an advanced pulmonary adaptation, excellent motor control, and low arousal.
60-80 seconds --> Advanced. Reflects a healthy pulmonary system, good motor control, and relatively low arousal.
40-60 seconds --> Intermediate. This range generally improves quickly with a focus on CO2 tolerance training.
20-40 seconds --> Average. Moderate to high arousal state. Breathing mechanics need improvement.
<20 seconds --> Poor. Very high arousal and stress sensitivity.
For more information on how and when to use these breathing patterns check out our SH//FT Breathe Programs or sign up for an Art of Breath Seminar.