Kumbhaka & The Power of CO2
Humans can survive weeks without food, days without water, yet mere minutes without oxygen. In elementary science classes, we learn that humans interact in symbiosis with the plant kingdom. We breathe in that vital oxygen produced by plants, and they breathe in the “waste product” of our respiration: carbon dioxide. This has led to the conception of carbon dioxide as an unimportant by-product compared to the life-giving O2 molecule. But what if I told you that it is actually CO2, that “waste” gas, that calms the body and enables oxygen to reach our cells?
The Vedic texts (passed down from the 15th to the 5th century BCE) explained that pranayama is not pranayama unless it includes Kumbhaka, otherwise known as breath holds. It seems counterintuitive. How could holding your breath be a necessity of a breathing practice? Shouldn’t we breathe more to get more oxygen into the body? We now have the tools of modern science to validate what pranayama practitioners have felt for so long: That breathing less will oxygenate us more. With more oxygen reaching our cells, our bodies can move, think, and rest more efficiently.
But how is this possible?
It all comes down to a fundamental biochemical process called the Bohr Effect. First described in 1904 by Danish psychologist, Christian Bohr, this phenomenon explains why you might see doctors giving panicked patients paper bags to breathe into.
The Bohr Effect works like this:
With lighter, slower, or paused breathing, carbon dioxide levels rise in the blood and lungs, blood pH drops, creating a slightly more acidic environment. As a result, the oxygen molecules in the blood lose their affinity for hemoglobin, which is the protein component of red blood cells that carries 98% of oxygen in the blood. When oxygen molecules become unbound from hemoglobin, they are taken up by other cells and tissues of the body to create energy for our bodies to use.
Moral of this scientific story? If you want more oxygen to reach the cells in your body, you are better off breathing less, not more. It’s all because carbon dioxide triggers the release of oxygen from the blood into the rest of the body.
The Bohr Effect
↑ CO2 in the blood → ↓ Blood pH → O2 and hemoglobin dissociate → ↑ O2 in the tissues
Increasing levels of CO2 in the blood sounds straightforward, but can indeed be quite challenging. Carbon dioxide is our body’s primary stimulus to breathe. With increased CO2 in the blood, feelings of breathlessness or air hunger signal discomfort to the brain. The greater the discomfort someone feels, the lower the CO2 tolerance they most likely have. When we have a low tolerance to CO2, the body is more likely to engage in oral, fast, shallow, upper-chest breathing to compensate (AKA hyperventilation). It’s important to remember that “hyperventilation” is simply breathing in excess of the body’s metabolic requirements. In other words, we could be overbreathing even if we aren’t engaging in dramatic, panicked breathing. Indeed, most people are breathing too much. A completely functional breather may be breathing anywhere from 6-10 breaths per minute. The more breaths per minute, the more oxygen in the blood.
Oxygen has an excitatory effect on the nervous system, whereas carbon dioxide has a calming effect. The more comfortable we can get with greater levels of CO2 by slowing respiratory rate and decreasing respiratory volume, the more of its benefits we will receive. These include dilation of airways and blood vessels, and greater uptake of oxygen throughout the body. Hence the success of that nifty paper bag– rebreathing CO2 can help elicit a tranquilizing effect. Ultimately, a person’s baseline breath ought to be light, slow, and deep– the opposite of hyperventilation. When a person’s breath pattern is like this, they most likely have a higher tolerance to CO2.
In addition to the benefits of increasing CO2 for the nervous system and mental health, it also is a fantastic way to improve your overall fitness. Think of how much easier it would be to take a run if you felt less breathless. Not to mention, a greater CO2 tolerance enables quicker recovery due to the adaptations the body makes to higher levels of acidity which reduces fatigue.
The good news is that we can train our tolerance to carbon dioxide, just as we would train the strength of any muscle. Overtime, we can develop a resistance to stress, enabling our physiology to impact our psychology. One such way to improve your CO2 tolerance is through the ancient art of Kumbhaka. By practicing holding the breath, we can quickly and acutely raise levels of CO2 in the blood, releasing more oxygen to our tissues, and thus conditioning the body to be less reactive to physiological and psychological stress.
There are four steps in the process of respiration: inhale, pause, exhale, pause. The two natural pauses, or retentions, are the opportunities to practice Kumbhaka. The two types of Kumbhaka refer to the two steps of the breath cycle when you engage in a breath hold. Antara Kumbhaka refers to the breath hold after the inhalation, whereas Bahir Kumbhaka refers to the breath hold after the exhale. For the purposes of balancing the nervous system and accessing effects of carbon dioxide more quickly, it is most helpful to practice the latter, Bahir Kumbhaka. This is because the lungs are emptied and CO2 levels rise more rapidly in the blood.
It is also important to take into consideration the duration of the breath hold, as eliciting small, medium, and large sensations of air hunger will have different effects on the body. Longer and stronger breath holds can be too up-regulating if not done carefully, and thus it is helpful to understand your initial tolerance to carbon dioxide before practicing Kumbhaka.
Thankfully, the Oxygen Advantage®, a breath training methodology developed by Patrick McKeown over the last 20 years, has a simple and accurate way to diagnose your tolerance. It’s called the “BOLT Score”, which stands for Body Oxygen Level Test. You can perform it like this:
Take a normal, silent inhale through the nose.
Take a normal, silent exhale through the nose.
Hold your nose with your fingers to prevent air from entering your lungs.
Use a timer to count the number of seconds until you feel the first distinct desire to breathe in.
The number of seconds recorded is your BOLT score.
The inability to hold the breath for more than 20 seconds suggests a disturbance to the breathing pattern or dysfunctional breathing. Don’t worry, improving your CO2 tolerance through Kumbhaka can help within a matter of weeks.
Below I’ve outlined a simple Kumbhaka practice based on your BOLT score that you can do while walking. This will make it easier to integrate into your daily activity if carving out time for a seated breathing practice is not available to you. Always take caution when practicing breath holds, listen to your body, and breathe normally if it becomes too intense or you begin to feel lightheaded. Note: Breath holds are not suitable for people who are pregnant or who have severe health conditions.
10 seconds or less
-Take a regular inhale through your nose.
-Take a regular exhale through your nose.
-Pinch your nose and hold your breath for 5 paces.
-Pause and inhale gently, then return to normal breathing.
-Rest for one minute and repeat up to 10 times.
20 seconds or less
-Take a regular inhale through your nose.
-Take a regular exhale through your nose.
-Pinch your nose and hold your breath for 10-15 paces.
-Pause and inhale gently, then return to normal breathing.
-Rest for 30-60 seconds and repeat up to 10 times.
20-30 seconds
-Begin walking and take a regular inhale through your nose.
-Take a regular exhale through your nose.
-Pinch your nose and hold your breath for 20-25 paces.
-Continue walking, inhale gently, then return to normal breathing.
-Begin again after you feel you’ve recovered and can breathe easily through the nose.
-Repeat up to 10 times.
Remember, these practices are not about being competitive with yourself, but rather developing the body’s adaptivity and resilience. We don’t practice breathing just to be good at breathing. We improve our breathing to be better at life. When our bodies and minds have a lower arousal threshold for stress, we can weather heavier storms and experience greater joy. It’s called a yoga “practice” for a reason.
If you would like to learn more about breath holding practices, you can check out my FREE Breathing Class, every Wednesday at 7:30am ET on BetterYoga.Net.