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The science behind High Ventilation Breathwork

   The science behind High Ventilation Breathworkfeatured image


Breathwork involves consciously changing our breathing patterns and comes in many shapes and forms, each with its own set of rules and benefits. It's like a buffet of breathing styles, from slow, calming breaths to quick, energizing ones. Let's dive into this world of breathwork, shall we?

Let's start by understanding the contrast between slow and fast breathing. Picture yourself taking deep, slow breaths, fewer than 10 per minute, versus engaging in rapid breathing, where you're inhaling and exhaling at a much quicker pace. In this article, we'll zoom in on High Ventilation Breathwork (HVB)—the type that gets your lungs working overtime.

Slowing down your breathing is widely recognized for its ability to calm your heartbeat and reduce stress, shining in the spotlight of numerous health studies. But what's the deal with speeding up your breathing? While it hasn't been as thoroughly studied, HVB shows promising signs of benefiting our health too.

Prolonged hyperventilation, a critical aspect of HVB, involves breathing beyond the body's normal oxygen needs and carbon dioxide release. This activity disrupts our internal balance, leading our bodies to adapt through a process known as allostasis. Allostasis is how our body manages stress, striving to return to stability but by adjusting its typical functioning parameters.

In the following sections, we’ll give a brief overview of the function of breathing and what makes breathing so unique, before we dive into the nitty-gritty of the neurophysiological mechanisms that help explain what we experience when we perform HVB.


This article is about High Ventilation Breathwork, which can be defined as breathwork that has an increase in minute ventilation (the volume of gas you breathe per minute) higher-than-normal rate/depth of ventilation. We want to emphasize that minute ventilation is only one factor of these holistic practices and rituals, that risks oversimplifying some of these ancient practices. But it’s an important one, and it makes it a bit easier to illustrate the science and some of the mechanisms in which those types of breathwork affect our physiological selves.

Another side note here is that some of the scientific explanation given here is based on research of hyperventilation. Compared to slow-paced breathing, HVB doesn't have the same amount of research just yet. So even though hyperventilation and HVB are not the same, we can learn about some of the physiological mechanisms present in HVB by looking at research on hyperventilation.

The purpose and physiology of breathing

Ventilation, or breathing, has two main jobs:

  1. Getting oxygen (O2): We breathe in oxygen because our bodies need it to create energy in a process called aerobic metabolism.
  2. Getting rid of carbon dioxide (CO2): We breathe out carbon dioxide, which helps keep the body's pH level—its acid-base balance—just right, between 7.35 and 7.45. This balance is super important for our cells to work properly.

1. Acquiring Oxygen (O2) for Energy

Our cells use oxygen to make energy from food. This process is called aerobic metabolism. It's very efficient and turns food (like glucose) into ATP (energy), water, and carbon dioxide (CO2).

When we breathe, we bring oxygen into our lungs. From there, it goes into our blood and gets carried all around our body to where it's needed. This carrying function is performed by a protein in red blood cells called hemoglobin. Oxygen sticks to this molecule, gets transported, and then detaches again where oxygen is needed. It's important to note here that how well it sticks, can change based on how acidic or basic our blood is. Which - as you'll see in a minute - is influenced by CO2 levels.

2. Getting Rid of Carbon Dioxide (CO2) to Keep Balance

So turning oxygen into energy generates CO2 as a byproduct. This CO2 doesn't just accumulate inside the cells where it's produced; rather it diffuses from areas of higher concentration within the cells to areas of lower concentration in the surrounding blood. The blood then picks up this CO2, transporting it to the lungs where it can be expelled from our body.

Now if you paid attention in biology classes you might say ‘CO2 is removed from the body since it’s a waste gas’. Right, BUT there’s more to it. The amount of CO2 plays a critical role in how acidic or basic our blood is. The higher CO2 levels, the lower the pH levels (more acid); and vice versa the lower the CO2 levels, the higher the pH levels (more basic/alkaline). The pH of our body is critical because it is essential for many life-sustaining processes, including oxygen delivery to tissues. This implies we need enough CO2 to get oxygen delivered where we need it.

The CO2-rich blood gets transported from the tissues that generated the CO2 towards the lungs. Once there, it diffuses from the blood into the alveoli of the lungs and we expel it by breathing out.

So breathing out, or exhaling, is how we reduce the CO2 in our system and maintain a critical pH balance. In fact, our brains have special sensors that notice when CO2 levels change. These sensors are part of our brain's oldest areas, showing just how fundamental this is for our survival. Exhaling to remove CO2 from our bodies is deeply rooted in our survival instincts and is closely linked to our urge to breathe.

What makes breathing so unique: volitional control

Our body has several 'homeostatic reflexes' that are essential to keeping us alive like thermoregulation and maintaining appropriate blood sugar levels. Breathing is involved in two of such homeostatic reflexes critical to our survival:

  • Managing oxygen levels
  • Managing our blood's acid-base balance through managing carbon dioxide levels

By default, the autonomic nervous system (ANS) seamlessly regulates our breathing to maintain these vital balances, even during sleep, adjusting automatically without conscious effort. However, what makes breathing so incredibly unique is that we can take conscious control and override the autonomic control of our breathing. That isn't possible for any other of our body's reflexes crucial to our survival! This ability to assume control over our breathing is called volitional control, and is connected to how humans have evolved over time, including being able to talk.

By thus by controlling our breath, we can either ensure the buildup of CO2. We simply need to hold our breath or breath faster and/or deeper which increases our minute ventilation. Minute ventilation refers to the total volume of air inhaled and exhaled per minute, directly influencing our body's CO2 levels.

Building up CO2 in our body is limited, because we can only hold our breath for so long. In fact, when we hold our breath and feel the urge to breathe again, it’s not to take in air, but it’s the need for our bodies to expel these excessive amounts of CO2 that built up in the body! Our bodies can tolerate longer deprivation of oxygen, than it can tolerate high levels of CO2!

The best part of this? We can train our CO2 tolerance and thus get better at breath holding by training, like what divers do. But beyond a certain point, our body's reflexes take over to make us breathe again. On the other hand, we can drastically reduce our CO2 levels for prolonged time because we can breathe fast for a long time. Anyone can do it, without needing special training. This is exactly what happens when someone hyperventilates. And it lowers our CO2 levels more than usual, with very (if done intentionally) interesting experiences as a result.

The most fascinating aspect is that while we can manipulate CO2 levels in both directions, we truly excel in one: reducing CO2 by ramping up our minute ventilation. Because even though we can enhance our CO2 tolerance and get better at breath holding through training - there's a limit to this. Eventually our body's reflexes compel us to breathe. Conversely, we can greatly lower our CO2 levels for an extended period by increasing our minute ventilation—breathing faster and/or deeper. This doesn't require any special training but reduces our CO2 levels substantially. If done intentionally, this can lead to interesting experiences.

Now that we've covered how breathing impacts CO2 levels and keeps our body's pH levels in check, we can dive deeper into how High Ventilation Breathwork (HVB) actually impacts our minds and bodies. We’ll first cover the effects it has on our brain's activities, the automatic controls of our body, and the hormones swirling through our bloodstream. And then we’ll try to bring all of that together to make an educated guess on how HVB can produce the altered states of consciousness that you’ll hear practitioners rave on about.

The neurophysiological mechanisms behind HVB

The neurophysiological effects of HVB can be explained by three key mechanisms:

  1. Neurometabolic: relating to the biochemical processes and activities within the brain and nervous system including conversion of food to energy, eliminating waste products etc.
  2. Autonomic: involving the involuntary nervous system that controls our heart rate, digestion, and relaxation responses;
  3. Endocrine: involving glands that secrete hormones directly into the bloodstream to regulate various body functions.

Through these mechanisms, HVB can have a profound effect on our mental and physical state. Let's explain them one by one.

Neurometabolic effects of HVB

We now know that HVB leads to lower-than-normal levels of CO2 in your blood. We breathe out too much CO2. Hypocapnia, in fancy terms.

As we've also seen, CO2 isn't just waste gas; it plays a pivotal role in maintaining a stable blood pH between 7.25-7.45. When CO2 levels drop, the pH goes up so we enter a state called respiratory alkalosis. Your blood becomes less acidic.

One of the first things that happens as a result is your hemoglobin - those red blood cell proteins that ferry oxygen around your body - gets even stickier to oxygen thanks to the Bohr effect. Essentially, hemoglobin holds onto oxygen tighter than a toddler with their favorite toy. This means less oxygen is released to your tissues, despite you breathing more of it in.

As we’ll explain in a second, this has an effect on your brain’s excitability. You can think of excitability of your neurons like their readiness to fire or send a message. Consider neurons to be light switches in your brain that turn on with a specific signal. If the switch is too sensitive, it might flick on too easily; if it's not sensitive enough, it might not turn on when needed. This balance is crucial for your brain to function smoothly, affecting how you think, move, and feel.

So even though excitability sounds like something you’d want for your brain in order to perform, you don’t want it to get too high. Because if you want to focus, for example, it requires that certain circuits in your brain are more active than everything else. The signal-to-noise ratio needs to be high. However, if your brain has a high level of excitability, more and more neurons start to fire making the noise part of that equation much higher. And so things like focusing become much harder.

Scientists will tell you that’s because the gamma waves in our brain get disrupted. Gamma waves are patterns of activity in our brain that occur at a frequency range typically between 30 to 100 Hz. These are thought to be crucial for brain functions like attention, memory, and perception because they help integrate information across different regions of the brain. Normally, the neurotransmitter GABA helps regulate neuronal excitability, ensuring neurons do not become overly active. But respiratory alkalosis can weaken this inhibiting effect of GABA, which leads to heightened neuronal excitability. This, in turn, disrupts the functioning of these gamma oscillations.

If you thought that was a wilde ride, then you’re in for a treat. Because there is another way in which HVB makes your neurons more trigger-happy than usual.

Parallel to the sticky oxygen in the blood and the neurons firing power increasing, the drop in CO2 also causes your blood vessels to narrow in a process called vasoconstriction, which reduces the blood flow in your brain. With your blood vessels tighter and giving off less oxygen (thanks to hemoglobin's new clinginess), your suddenly brain finds itself low in oxygen supply, or hypoxia.

Now, even though we haven’t found direct evidence to back this up, it's suggested that this change in blood flow might not affect all parts of the brain equally. Some areas, like the emotional brain, could still receive sufficient blood. While less blood would flow to the prefrontal cortex, which manages cognitive functions. This could lead to a decreased ability to control or inhibit emotional responses, resulting in a more pronounced emotional release.

A final neurometabolic effect comes from this low-oxygen situation. It forces your brain to adjust its energy strategy, shifting towards glycolysis—a way of making energy without oxygen. This shift leads to a buildup of lactate, which then pokes the Locus Coeruleus, a brain region that sounds the alarm by releasing epinephrine (adrenaline), heightening alertness and preparing your body for action. Additionally, the low levels of oxygen further disrupt the ‘calming’ effect of GABA neurotransmitters on our neurons. . Which again… further increases our brain’s excitability.

So you can see how by breathing, you’ve got control over the state of your brain. This is why in scientific circles there is a well-known quote from a paper by Balistrino and Somjian written in 1988 that goes: “The brain - by regulating breathing - controls its own excitability”.

Autonomic effects

Now before we look at what happens to our nervous system during HVB, let’s take a step back and see how this operates under normal circumstances. When breathing normally, our diaphragm, the umbrella-shaped muscle separating our thorax from our belly, expands and contracts while breathing. When you breathe in, the diaphragm contracts, opening the umbrella, making the thoracic cavity larger. This draws air into our lungs. When you breathe out, the umbrella closes, making the thoracic cavity shrink and pushing the air out of our lungs.

How the ANS works when breathing

When exhaling air out of your lungs, this decreases your thorax, thereby squeezing the organs within: your lungs and heart literally become pressured. Consequently, the blood pressure in our heart increases.

Our nervous system detects increases in blood pressure through specialized neurons , known as baroreceptors. When those baroreceptors notice a blood pressure increase, they send signals to the medulla,which is the lower part of the brainstem that contains the cardiac and respiratory centers (amongst others). The medulla in turn increases the neural activity of the vagus nerve. The vagus nerve is part of the parasympathetic nervous system and has an inhibitory function on our heart rate (HR). So increasing the activity of the vagal nerve means that the HR goes down.

In summary, when we exhale under normal circumstances:

  1. the diaphragm goes up
  2. our thoracic cavity shrinks
  3. our heart shrinks with it
  4. the blood pressure increases
  5. the baroreceptors detect this and send signals to the medulla
  6. the medulla increases the activity of the vagus nerve
  7. the vagus nerve inhibits the heart rate more
  8. the heart rate slows down
  9. the blood pressure decreases again

When we inhale, the opposite happens:

  1. the diaphragm goes down
  2. our thoracic cavity expands
  3. our heart expands with it
  4. the blood pressure decreases
  5. the baroreceptors sense less pressure and so reduce their signal to the medulla
  6. the medulla reduces the activity of the vagus nerve
  7. the vagus nerve inhibits the heart rate less
  8. the heart rate speeds up
  9. the blood pressure increases back

Our ANS can be in very different states whether we’re inhaling or exhaling. Here we see how breathing in means our HR goes up, breathing out means it goes down.

Now here’s the trick. When we are hyperventilating, the sensitivity of these baroreceptors get attenuated. This means that they'll respond less to the same blood pressure, sending less signal to the medulla, which reduces the activity of the vagal nerve, which increases our heart rate. In essence: HVB suppresses the baroreflex and shifts the sympathetic/parasympathetic autonomic balances toward the sympathetic.

This is very unique because it makes breathing one of only two mechanisms (the other being the control over our skeletal muscles) through which we can consciously change autonomic activity in our body.

Endocrine effects

Now bear with us. There is a third important physiological effect that comes into play during HVB: our hormones.

The hypothalamic-pituitary-adrenal (HPA) axis is our body's main stress response system. It consists of three components: the hypothalamus (a part of the brain located below the thalamus), the pituitary gland (a pea-shaped structure located below the hypothalamus), and the adrenal (also called "suprarenal") glands (small, conical organs on top of the kidneys). It's these organs and their interactions that constitute the HPA axis.

This neuroendocrine system plays a pivotal role in linking perceived stress with physiological reactions, primarily through the release of hormones like cortisol, which activate various short-term stress responses.

The previous section discussed how HVB causes a shift in the autonomic balance between the sympathetic and parasympathetic nervous systems. Such shifts often influence neuroendocrine functions, notably affecting the HPA axis. This connection indicates that voluntary hyperventilation (HVB) could also impact the hormonal balance in our body. Indeed, research suggests that HVB can engage the HPA axis both directly and as a response to hypocapnia/hypoxia, which the body interprets as stressors. This engagement results in increased levels of adrenal stress hormones like cortisol in the circulation.

Cortisol, often referred to as the "stress hormone," plays multiple roles in the body. Most people think of cortisol as a harmful molecule. But that is only the case when it is chronically elevated. In short bursts, cortisol can be incredibly useful. It helps mobilize energy stores, suppresses the immune system, and assists in managing stress, making it vital for survival.

A  study  involving the Wim Hof breathing method (WHbM) practitioners found that they experienced higher spikes in cortisol but also demonstrated quicker recovery and stabilization of cortisol levels post-breathwork compared to individuals not practicing WHbM. These findings hint at the possibility that HVB's modulation of HPA axis activity, particularly cortisol release, could offer therapeutic benefits for conditions associated with prolonged high cortisol levels, such as anxiety and PTSD. However, these ideas remain speculative as more research is needed to fully understand cortisol levels' dynamics post-HVB and during recovery phases.

The apparent paradox between the positive experiences reported by individuals engaging in HVB and the associated increase in circulating stress hormones can be explained by the concept of "eustress" or beneficial stress. Think of it like taking medicine: low amounts don't do much and very high amounts can actually harm us, but somewhere in between is the perfect amount that gives us the most benefit. Such a response is called an hormetic response to stress, and is illustrated on the figure below.

This beneficial stress effect of HVB can potentially aid in reversing dysregulated or defective stress responses. And it makes our body adapt, enhancing our resilience to future stressors—whether emotional, cognitive, or biological—by effectively "training" the body's stress response systems to handle stress more efficiently.

How HVB might induce Altered States of Consciousness (ASC)

HVB can induce what are called Altered States of Consciousness (ASC). The fact that you've got a shift in your autonomic balance, adrenaline and cortisol is rushing through your body and there is less oxygen available in your brain are of course going to change the way you experience things. But that's not the only thing going on.

A significant portion of participants in Grof ® Breathwork, for instance, report experiencing ego dissolution - a state where the sense of self becomes blurred or entirely vanishes. Such experiences, offering substantial therapeutic value, are more likely during prolonged, continuous hyperventilation practices without breaks.

Even though there is no evidence for it yet, researchers have hinted that this mystical experience can occur because HVB challenges our body's equilibrium. Our brain is constantly perceiving and trying to understand the internal conditions by integrating various signals (like blood pressure, CO2 levels, nutrient store levels etc). This process is called interoception, and we call those signals interoceptive signals. In this way, our brain can send signals to e.g. motivate us to find food when we're feeling hungry. Or to adjust our breathing so our CO2 levels get back to normal.

While one part of your brain is telling you to slow down your breathing to fix the balance of CO2 and acidity in your body, your volitional part keeps the deep, fast breathing going. So HVB messes with this system that tries to integrate and regulate those interoceptive signals. The brain's prediction system, which normally helps you adjust to changes, can't keep up. You're doing something (breathing fast) that goes against what your body is telling you to do, leading to a kind of sensory overload.

This intense experience can make you feel very different, possibly even leading to a feeling of being detached from yourself or the world around you, similar to dreaming or feeling outside of your body. It's like the part of you that controls your actions splits from the part that feels what's happening inside, creating a unique mental state. Some researchers think this could explain why some people feel a strong sense of relaxation or disconnection from their usual self during and after breathwork practices.


Breathing is fundamental for acquiring oxygen to fuel our metabolism and removing carbon dioxide to maintain acid-base balance. Its uniqueness lies in our ability to control it voluntarily, allowing us to influence our nervous system directly. Neurophysiologically, HVB impacts us on multiple levels: neurometabolically, it alters brain chemistry; autonomically, it shifts our nervous system's balance; and endocrinologically, it affects our stress response hormones. Despite its potential, research into HVB's clinical applications is still emerging, highlighting a need for more rigorous studies to understand its benefits fully and integrate it effectively into therapeutic practices.


What happens to the brain in High Ventilation Breathwork?

In HVB, we breathe out a lot of carbon dioxide so our blood becomes more alkaline. This makes oxygen cling more tightly to hemoglobin and causes our blood vessels to narrow. So less oxygen reaches our brain. The alkaline environment also makes our brain's neurons less inhibited, meaning they fire more readily, which can disrupt our memory, attention, and perception. Additionally, calcium levels in our blood drop, making our brain even more excitable. With less oxygen around, our brain starts producing energy in a way that creates lactate, leading to the activation of a brain area that releases adrenaline, making us feel more alert. Our autonomic system shifts towards our "fight or flight" system and stress hormones like cortisol get released. In this highly excitable state, with adrenaline and cortisol rushing through our brain, the clash between the autonomic part that’s signaling to slow down and the conscious part that keeps going, can induce altered states of consciousness, blurring our usual sense of self.

How does HVB compare to other forms of breathwork in terms of effectiveness for specific health outcomes?

High Ventilation Breathwork (HVB) and other breathwork practices both show effectiveness in improving stress and mental well-being, with HVB focusing on fast-paced breathing to engage specific neurophysiological responses. The direct comparison of effectiveness for specific health outcomes between HVB and other forms remains underexplored in research, highlighting a gap in understanding their relative benefits.

What are the long-term effects of regularly practicing HVB on mental and physical health?

The long-term effects of regularly practicing High Ventilation Breathwork (HVB) on mental and physical health are not yet fully understood due to the scarcity of specific long-term studies. However, existing research on breathwork suggests potential benefits such as improved stress management, enhanced emotional well-being, and possibly better cognitive function. Rigorous, longitudinal research is needed to clarify HVB's long-term impact on health outcomes and to understand its therapeutic potential and safety profile comprehensively.

Are there any long-term studies on the effects of HVB on brain plasticity and cognitive functions?

To date, no long-term studies specifically examine High Ventilation Breathwork (HVB) and its effects on brain plasticity and cognitive functions. The area remains ripe for investigation to elucidate how sustained HVB practice might influence cognitive health and neuroplastic changes over time

What specific safety guidelines should individuals follow when practicing HVB to avoid potential risks

Individuals practicing High Ventilation Breathwork (HVB) with potential risks like dizziness, fainting, and changes in blood pressure. It's advised to start with guidance from a qualified instructor who can adjust the practice to your needs and monitor you for adverse reactions. Practitioners with health conditions like cardiovascular issues, epilepsy, or panic disorders should consult healthcare providers before starting HVB. Avoid doing this in or near a body of water to avoid a shallow water blackout. During sessions, maintaining a comfortable pace, avoiding overexertion, and practicing in a safe environment where one can sit or lie down if feeling lightheaded are crucial. Ensuring proper hydration and avoiding heavy meals before practice can also help minimize discomfort.

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