Since studying breathwork, I’ve learned that CO2 is not simply a by-product of breathing. It’s essential to have a level of CO2 in our lungs to signal the brain the need to breathe, dilates the body’s arteries for better blood flow, regulates oxygen absorption into the bloodstream, and to regulate the body’s pH. Too low CO2 is linked with anxiety, asthma, hypertension and blood pressure, and more.

This simple(?) test determines your tolerance to CO2, through timing how long you can hold your breath before your body shows the first signs of air hunger. It’s sometimes called the Baseline Score, or the BOLT score, and is based on Buteyko’s work.

Many of us who have never learned to breathe properly (and have health/stress issues) will probably start with a score lower than 20. When breathing changes and the score is above 25, many symptoms starts to normalise. A score of 30 or more is considered healthy, while above 40 is excellent.

Mouth breathing, shallow and fast breathing reduce the CO2 levels in the body. If your score is low, then a good starting point is consciously beginning to breathe through your nose, and start to breathe more slowly (try coherent breathing) to begin to have your body learn to tolerate the higher levels of CO2 in lungs for good health. With time, some breath holds can be incorporated to help further build CO2 tolerance.

I find that doing this in the morning is best, soon after waking, before life gets started.

Sit upright in a comfortable chair, with your phone or other device open to stopwatch.

Take a few gentle breaths in and out (through the nose, of course) and begin to relax.

Take a normal breath in through the nose.

Then a normal breath out through the nose – to where the exhale lands, then pinch your nose and start the timer.

Count the seconds until you have the first distinct desire to breathe – not when you’re gasping for air. Once let go of your nose, breathing should be easy and natural – if needing to take a deep breath after, then you’ve gone too far.

It might take about a week of daily practice to get a good feeling of where you’re at.