Posted on September 17, 2021 by Emily Forbes

In last week’s blog I gave you some ins and outs of breath work. Today, we’re going deeper into the role of carbon dioxide in breathing and our tolerance to it. Carbon dioxide (CO2) is often seen as a waste product of breathing but I’m here to tell you how you can use CO2 to improve your health!

Carbon dioxide is actually the main controller of breathing, not oxygen! When our CO2 levels increase, signals are sent to our breathing muscles to activate an inhale. And like I mentioned last week, CO2 is needed for oxygen to be released into the tissues and cells. It also dilates blood vessels which allows for better oxygenation.

Most people in modern day are over-breathers, meaning they’ll have low CO2 levels (chronic hyperventilation). As CO2 is required for a healthy respiratory system and overall health, these low levels mean we have a low tolerance to CO2 – which is associated with anxiety states and our ability to manage stress.

By improving your CO2 tolerance you can reduce anxiety, be more stress-adaptive, have lower cortisol levels, improved mental and physical performance. So whether you’re an athlete or a desk worker, everyone can improve their CO2 tolerance, and its easy to do.

Test your tolerance:

You’ll need a stopwatch/timer for this test.

  • Sit somewhere comfortable, where you can sit straight and and be relaxed.
  • Take 3 breaths normally through your nose.
  • On your 4th breath, inhale through the nose, filling your lungs completely.
  • Start your timer and slowly exhale through your nose. You want to exhale for as long as you can so don’t rush it. Try to stay as relaxed as possible. Doing this first thing in the morning is a truer result of your CO2 tolerance.
  • Stop the timer when you run out of air, or you stop or swallow.
  • Record your time.

Interpreting the results:

  • >80 seconds = Elite. Advanced pulmonary adaptation, excellent breathing and stress control.
  • 60-80 seconds = Advanced. Healthy pulmonary system. Good breathing and stress control.
  • 40-60 seconds = Intermediate. Can improve quickly with a focus on CO2 tolerance training.
  • 20-40 seconds = Average. Moderate to high stress/anxiety state. Breathing mechanics need improvement.
  • <20 seconds = Poor. Very high anxiety and stress sensitivity. With low pulmonary capacity.

Improve your CO2 tolerance:

  • Try to nasal breathe when training whenever possible.
  • Incorporate breathing exercises which work with nasal breathing and breath holds.
  • Exercise 1: Easy: Inhale 10 sec: exhale 10 sec; Intermediate: Inhale 10 sec: hold 10 sec: exhale 10 sec; Hard: Inhale 10 sec: hold 10 sec: exhale 10 sec: hold 10 sec. [Box breathing]. If 10 sec is too hard on the exercises, start with as many seconds as you can do and build up. Do exercises for 1 min. Breathe normally for 1 min. Repeat 3-6 times
  • Exercise 2: Easiest: Inhale 3 sec: hold 6 sec: exhale 3 sec; Easy: Inhale 6 sec: hold 12 sec: exhale 6 sec; Intermediate: Inhale 6 sec: hold 18 sec: exhale 12 sec; Hard: Inhale 6 sec: hold 24 sec: exhale 12 sec.

Retest your tolerance test after a couple of weeks breath training. Watch your stress levels drop and your gym performance improve!

Emily x