Functional Breathwork: Use Interoception to Regulate Your Nervous System

Your breath is already training your nervous system

Most people discover breathwork as a technique: box breathing, Wim Hof, pranayama, coherent breathing, a deep-dive session with music, a nervous-system reset before sleep.

Conni Biesalski’s useful distinction is simpler and more practical: there are peak-state breathwork practices, and there are functional breathing practices that change how you breathe through ordinary life.¹

That distinction matters because your baseline breath is not neutral. Mouth breathing, upper-chest tension, frequent sighing, audible breathing, or feeling like you cannot get a satisfying breath can all keep feeding a threat-shaped physiology, even when nothing dramatic is happening.⁵ ✻1Functional breathwork is less glamorous than peak-state breathwork. That is part of the point. It trains the boring baseline your nervous system lives inside all day.

The guide below turns Conni’s conversation with Jonny into a practical map: how to notice your breath, how to choose the right kind of practice, and how to use interoception — the ability to sense what is happening inside your body — as the missing feedback loop.

Breathwork has two very different jobs

Conni separates breathwork into two broad camps.

The first is daily functional breathing: practices that improve how you breathe at rest, under stress, while walking, before sleep, and during ordinary moments of pressure. These tend to be gentle, nasal, quiet, and repeatable. The goal is not a massive state shift. The goal is a more resilient baseline.

The second is transformational breathwork: longer, more activating sessions such as conscious connected breathing, holotropic-style work, rebirthing, or neurodynamic breathwork. These can produce altered states, emotional release, and powerful inner material. They may be useful in the right container, but they are not the same thing as training a functional day-to-day breathing pattern.¹

This is where many people get tangled. A practice can feel profound and still be poorly matched to the nervous-system adaptation you need.

If your system is already living in high sympathetic charge — fast mind, poor sleep, urgency, jaw tension, heart racing, compulsive productivity — adding another intense breathing protocol every morning may reinforce the same physiology you are trying to unwind.

If your system is collapsed, foggy, depressed, or shutdown, a quiet sitting practice may send you further down the ladder before you have enough mobilisation to feel safe.

The question is not “Which breathwork technique is best?”

The better question is: what state am I in, and what kind of input would help my system find more range?

Interoception is the feedback loop

Interoception is your capacity to notice internal signals: hunger, fullness, bladder pressure, heartbeat, breath, temperature, muscular tension, emotional sensation, the first feather of stress before the dump truck arrives.²

Conni describes how many of us learn to live from the neck up. We think about our body more than we feel it. Then a device, a coach, a health scare, or a burnout event becomes the thing that finally tells us what the body had been signalling for months.

The research context is nuanced. Interoception is not simply “more body awareness is always better.” Anxiety is often entangled with bodily attention, negative appraisal, and difficulty interpreting signals; recent reviews find mixed results depending on which aspect of interoception is measured.³ That caveat is useful. The goal is not obsessive scanning. The goal is clearer contact plus better regulation.

For breathwork, interoception changes the practice from performance to feedback:

• Is this breath making me softer or more wired?
• Can I feel my ribs move, or only my shoulders?
• Am I breathing through the nose without strain?
• Does the exhale actually land, or am I forcing calm?
• Do I need stillness, movement, food, support, sunlight, or sleep before another protocol?

This is why Conni’s closing question is so good: “How’s my breath right now?”⁴

That question is the beginning of breathwork because it brings the breath out of abstraction and into direct contact.

A quick way to spot an unhealthy breathing pattern

Conni’s assessment is not a medical diagnosis. It is a practical first pass.

At rest, signs that your breathing may be carrying stress include:⁵

• breathing mostly through the mouth
• upper-chest or shoulder-dominant breathing
• audible, heavy, or noticeably effortful breathing
• frequent sighing or yawning
• irregular rhythm
• breathing faster than the situation requires
• feeling like you cannot get enough air
• tight neck, back, ribs, or diaphragm
• difficulty falling asleep or settling after stress

A more functional resting breath is usually quieter, lighter, slower, nasal, and more distributed through the diaphragm, ribs, belly, and a small amount of upper-chest movement. Conni gives an 80/20 cue: most of the visible movement around the lower ribs and belly, with some movement in the chest rather than rigid “belly-only” breathing.⁶

Jonny adds an important reframe in the episode: the issue is not a single number or a moral label. Breathing is adaptive. It should change when you run, lift, cry, sprint, laugh, speak, or face danger. The problem is when the pattern at rest keeps matching a threat that is no longer present.

That is the search-intent answer for “functional breathwork”: it is not about breathing perfectly. It is about restoring range.

CO2 tolerance is a capacity, not a stunt

One of the more useful myth-busting threads in the episode is carbon dioxide.

Many people assume better breathing means more air. Conni makes the opposite point: chronic overbreathing can reduce carbon dioxide levels, and CO2 is part of how the body regulates the urge to breathe, blood flow, and oxygen delivery.⁷

That does not mean everyone should start aggressively holding their breath. It means that becoming more comfortable with mild air hunger — gently, progressively, safely — can be part of retraining the system away from chronic overbreathing.

This is one reason Conni is cautious about daily Wim Hof-style hyperventilation, especially for already stressed, Type-A, overtrained, or anxiety-prone people.⁸ Those practices can feel incredible because they create intensity: adrenaline, altered sensation, and sometimes a temporary slowing of thought. But “I felt something big” is not the same as “my baseline breathing pattern became healthier.”

The clinical literature around dysfunctional breathing is still messy. Reviews describe it as common, under-recognised, heterogeneous, and difficult to measure cleanly; breathing retraining shows promise, but study quality and protocols vary widely.⁹ That is exactly why a sober approach matters here: avoid miracle claims, use the breath as a feedback-rich training tool, and dose the intervention to the person in front of you.

Practice

The 60-second functional breath check

Use this several times a day: before opening your laptop, after a meeting, before bed, or any time you notice yourself speeding up. You are not trying to fix the breath immediately. You are rebuilding the feedback loop.

1. Pause without performing calm. Let the body be exactly where it is for one breath.
2. Ask: how’s my breath right now? Notice nose or mouth, chest or ribs, fast or slow, smooth or jagged, quiet or effortful.
3. Find one place of movement. Put a hand on the lower ribs or belly and feel whether anything moves there.
4. Soften the exhale. Let the next three exhales become a little longer than the inhales, without forcing a giant breath.
5. Choose the next dose. If you feel wired, continue with 2–5 minutes of slow nasal breathing. If you feel collapsed, stand up, walk, shake, or get outside first.

If focusing on the breath makes you more anxious, back off. Track feet, room sounds, or contact with a chair first. Interoception should build safety, not become another test to pass.

Slow breathing is useful when the dose is right

Near the end of the episode, Conni recommends simple vagus-nerve practices, humming, and coherent breathing — roughly five seconds in and five seconds out — as accessible ways to support HRV and downshift state.¹⁰

The broader research picture is supportive but not magical. Systematic reviews of slow breathing suggest it can increase heart-rate variability and shift autonomic markers in a parasympathetic direction, with some evidence for reduced arousal and improved psychological state in healthy participants.¹¹ The mechanism is not one-button certainty, but the pattern is strong enough to make slow, voluntary breathing a sensible low-tech practice for many people.

The key word is voluntary. Slow breathing works best when it is not another way to dominate the body.

Try:

• nasal breathing when possible
• gentle diaphragmatic/rib movement
• an exhale equal to or slightly longer than the inhale
• mild rather than heroic air hunger
• short practices repeated consistently
• movement first if stillness drops you into collapse

Conni’s “dating breath” is a lovely field example: walk to the date, breathe in for four steps, breathe out for eight, and arrive with a body that has already processed some of the charge.¹²

That is functional breathwork doing its actual job — not producing a peak experience, but changing how you meet the next moment.

Key takeaways

• Breathwork is not one thing. Functional breathing and transformational breathwork serve different purposes.
• Interoception is the feedback loop that helps you choose the right practice for your current nervous-system state.
• A stressed resting breath often shows up as mouth breathing, chest dominance, sighing, yawning, noisy breathing, or feeling unable to get enough air.
• CO2 tolerance is trained through gentle capacity-building, not daily overbreathing heroics.
• Slow nasal breathing and coherent breathing can support HRV and downshift state when the dose is matched to the person.
• The simplest starting point is still Conni’s question: “How’s my breath right now?”

Free assessment

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Continue exploring

• Read Breathwork for Anxiety for a complementary guide on using the breath to meet anxiety without escalating it.
• Read How to Increase Your Nervous System Capacity for more on stress, controlled intensity, and recovery.
• Read How to Work With Chronic Anxiety for a deeper guide to anxiety loops, avoidance, and regulation.
• Try Reset Your Nervous System for a short practical reset.

References

1. Conni Biesalski, The Science of the Nervous System, Functional Breathwork Training and Our Sixth Sense of Interoception, around 18:27–24:07. She distinguishes daily functional breathing from longer transformational or dynamic breathwork sessions. ↩
2. Conni Biesalski, The Science of the Nervous System, Functional Breathwork Training and Our Sixth Sense of Interoception, around 24:43–29:57. ↩
3. For research context, a 2024 systematic review and meta-analysis found that anxiety is associated with certain self-reported interoceptive patterns — including negative evaluation of bodily signals and difficulty describing bodily signals — while also noting measurement overlap and mixed evidence across dimensions. See https://pubmed.ncbi.nlm.nih.gov/39427810/. A broader review similarly cautions that interoception is multidimensional and not captured by a single “body awareness” score: https://pmc.ncbi.nlm.nih.gov/articles/PMC11169962/. ↩
4. Conni Biesalski, The Science of the Nervous System, Functional Breathwork Training and Our Sixth Sense of Interoception, around 1:31:53–1:32:18. ↩
5. Conni Biesalski, The Science of the Nervous System, Functional Breathwork Training and Our Sixth Sense of Interoception, around 56:16–58:55. ↩
6. Conni Biesalski and Jonny Miller, The Science of the Nervous System, Functional Breathwork Training and Our Sixth Sense of Interoception, around 59:14–1:00:35. ↩
7. Conni Biesalski, The Science of the Nervous System, Functional Breathwork Training and Our Sixth Sense of Interoception, around 1:00:35–1:06:55. ↩
8. Conni Biesalski and Jonny Miller, The Science of the Nervous System, Functional Breathwork Training and Our Sixth Sense of Interoception, around 1:13:56–1:23:05. ↩
9. Boulding et al. describe dysfunctional breathing as a group of breathing-pattern disorders associated with dyspnoea and non-respiratory symptoms, and note that it remains poorly understood because of limited high-quality trials and measurement issues: https://pmc.ncbi.nlm.nih.gov/articles/PMC6534396/. A 2025 systematic review of nonpharmacological interventions found breathing retraining frequently reported positive effects but rated the overall evidence as low quality and heterogeneous: https://pubmed.ncbi.nlm.nih.gov/40345332/. ↩
10. Conni Biesalski, The Science of the Nervous System, Functional Breathwork Training and Our Sixth Sense of Interoception, around 1:24:10–1:27:27. ↩
11. Zaccaro et al. reviewed slow-breathing techniques and found evidence of increased HRV, respiratory sinus arrhythmia, and related psychophysiological changes, while noting that mechanisms and protocol definitions remain debated: https://pmc.ncbi.nlm.nih.gov/articles/PMC6137615/. A later systematic review and meta-analysis found voluntary slow breathing increased vagally mediated HRV during breathing, immediately after one session, and after multi-session interventions: https://pubmed.ncbi.nlm.nih.gov/35623448/. ↩
12. Conni Biesalski, The Science of the Nervous System, Functional Breathwork Training and Our Sixth Sense of Interoception, around 1:27:36–1:28:55. ↩