How Fit Are You? Meet the Body Oxygen Level Test (BOLT)
We first heard of the Body Oxygen Level Test while reading The Oxygen Advantage By Patrick McKeown. As far back as 1975, researchers noted that the length of comfortable breath hold time served as a simple test to determine relative breathing volume during rest and breathlessness during physical exercise. The Body Oxygen Level Test (BOLT) is a very useful and accurate tool for determining relative breathing volume during both rest and physical activity. The test is simple, safe, involves no sophisticated equipment and can be applied at any time…you can even do it while reading this post!
How the BOLT works:
When you hold your breath, you prevent oxygen from entering your lungs AND prevent excess carbon dioxide from exiting. As the breath hold continues, carbon dioxide accumulates in the lungs and blood, while oxygen levels slightly decrease. Since carbon dioxide is the primary trigger for breathing, the length of your breath hold time is influenced by how much carbon dioxide you are able to tolerate.
A low tolerance to carbon dioxide means that your threshold will be reached sooner, resulting in a lower breath hold time. Conversely, a good tolerance to carbon dioxide results in a higher breath hold time.
When your BOLT is lower, your breathing receptors are especially sensitive to carbon dioxide and your breathing volume will be heavier as the lungs work to remove any carbon dioxide in excess of programmed levels. However, when you have a normal tolerance to carbon dioxide and a higher BOLT, you will be able to maintain calm breathing during rest and lighter breathing during physical exercise. Win, win!
How to conduct the BOLT:
Take a normal breath in through your nose and allow a normal breath out through your nose.
Hold your nose with your fingers to prevent air from entering your lungs.
Time the number of seconds until you feel the first definite desire to breathe, or the first stresses of your body urging you to breathe. These sensations may include the need to swallow or a constriction of the airways. You may also feel the first involuntary contractions of your breathing muscles in your abdomen or throat as the body gives the message to resume breathing. (Note that BOLT is not a measurement of how long you can hold your breath but simply the time it takes for your body to react to a lack of air.)
Release your nose and breathe in through it. Your inhalation at the end of the breath hold should be calm.
Resume normal breathing.
Please be aware of the following important points when measuring your BOLT score:
To obtain an accurate measurement, it’s best to rest for ten minutes before measuring your BOLT score.
The breath is taken after a gentle exhalation.
The breath is held until the breathing muscles first begin to move. You are not measuring the maximum time that you can hold your breath.
If you do not feel the first involuntary movements of your breathing muscles, then release your nose when you feel the first definite urge or first distinct stress to resume breathing.
If you need to take a big breath at the end of the breath hold, then you have held your breath for too long.
Your BOLT is not an exercise to correct your breathing.
A few notes on the BOLT
You may find that the first time you measure your BOLT, you are surprised that your score is lower than expected (we know we were). Remember that even elite athletes can score a low BOLT! The good news is that your BOLT can easily be increased with a series of simple breathing exercises incorporated into your existing exercise program. A common starting BOLT score for an individual who exercises regularly at a moderate intensity will be approximately 20 seconds. If your bolt score is below 20 seconds you will probably find you experience breathlessness during exercise and symptoms of over-breathing during rest. The goal for our athletes is to increase their BOLT to 40 seconds, and this can be realistically achieved.
Improving your bolt score is an important key to attaining greater physical endurance. Improved tolerance to carbon dioxide means you are able to achieve a higher vo2 max and improved performance. Every time you improve your BOLT by just five seconds you will find that symptoms such as coughing, wheezing, chest tightness and breathlessness reduce drastically and performance improves!
Want to learn more? Book a session with one of our Breath Performance Coaches to learn how to implement more breathing into your current program.