Functional Breathwork: Use Interoception to Regulate Your Nervous System

Your breath is already training your nervous system

Most people find breathwork through a single door. Box breathing from a podcast. Wim Hof from a friend who got into cold plunges. Pranayama at a yoga retreat. Maybe a deep-dive session with music that cracked something open.

Conni Biesalski draws a useful line through all of it: there are peak-state breathwork practices, and there are functional breathing practices that reshape how you breathe through ordinary life.

Your baseline breath matters more than any single session, and most people never look at it. Mouth breathing, upper-chest tension, frequent sighing, audible breathing, or that persistent feeling of never quite getting a full breath can keep feeding a threat-shaped physiology even when nothing threatening is happening. ✻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.

This guide turns Conni's conversation 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 different jobs

Conni separates the landscape into two camps.

Daily functional breathing improves how you breathe at rest, under stress, while walking, before sleep, during ordinary pressure. These practices tend to be gentle, nasal, quiet, repeatable. The goal is a more resilient baseline, day after day.

Transformational breathwork includes longer, activating sessions: conscious connected breathing, holotropic-style work, rebirthing, neurodynamic breathwork. These can produce altered states, emotional release, and powerful inner material. In the right container they can be genuinely useful. But they are a completely different intervention than training your everyday breathing pattern.

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

If your system already runs hot (fast mind, poor sleep, urgency, jaw tension, heart racing, compulsive productivity), adding another intense breathing protocol every morning can reinforce the very physiology you are trying to unwind. If your system has collapsed into fog, depression, or shutdown, a quiet sitting practice may send you further down the autonomic ladder before you have enough mobilization to feel safe.

What state am I in right now, 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 full wave hits.

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

The research is nuanced. Anxiety often entangles with bodily attention, negative appraisal, and difficulty interpreting signals; recent reviews find mixed results depending on which dimension of interoception is measured.¹ The goal is clearer contact paired with better regulation: sensing what is there, then knowing what to do with the information.

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?" One sentence that brings the breath out of abstraction and into direct contact. It works every single time you remember to ask it.

What a stressed resting breath actually looks like

Conni's assessment is a practical first pass, a way to notice patterns before anything clinical.

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

• 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 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 chest movement rather than rigid "belly-only" breathing.

Breathing is adaptive. It should change when you run, lift, cry, sprint, laugh, speak, or face danger. The problem shows up when the resting pattern keeps matching a threat that left the room hours ago.

Functional breathwork is about restoring range.

CO2 tolerance and chronic overbreathing

Most people assume better breathing means more air. Conni makes the opposite case: chronic overbreathing reduces carbon dioxide levels, and CO2 plays a central role in regulating the urge to breathe, blood flow, and oxygen delivery.

That does not mean everyone should start aggressively holding their breath. Becoming more comfortable with mild air hunger, gently and progressively, 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. Those practices can feel incredible because they create intensity: adrenaline, altered sensation, sometimes a temporary quieting of the mind. But "I felt something big" is not the same as "my baseline breathing pattern became healthier."

The clinical literature around dysfunctional breathing remains messy. Reviews describe it as common, under-recognized, heterogeneous, and hard to measure cleanly; breathing retraining shows promise, but study quality and protocols vary widely.² 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 rebuilding the feedback loop. Let the breath respond on its own timeline.

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 works best when it builds safety. If it starts feeling like a test, you have gone too far.

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, five seconds out) as accessible ways to support HRV and downshift state.

Systematic reviews of slow breathing find increased heart-rate variability and a shift in autonomic markers toward parasympathetic activity, with some evidence for reduced arousal and improved psychological state in healthy participants.³ The mechanism is not fully mapped, but the pattern is consistent enough to make slow, voluntary breathing a sensible low-tech practice for most people.

The key word is voluntary. Forcing calm is still forcing.

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" makes this concrete: walk to the date, breathe in for four steps, breathe out for eight, arrive with a body that has already processed some of the charge.

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

Key takeaways

• Functional breathing and transformational breathwork serve different purposes and require different dosing.
• 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 builds through gentle, progressive exposure to mild air hunger.
• 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. 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 cannot be captured by a single "body awareness" score: https://pmc.ncbi.nlm.nih.gov/articles/PMC11169962/. ↩
2. 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/. ↩
3. 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/. ↩