The Science of Breathwork: Why Tetany Happens
Breathwork has surged in popularity as both a therapeutic and spiritual practice. From ancient yogic pranayama to modern holotropic sessions, controlled breathing can alter body chemistry and consciousness in powerful ways. One of the most striking experiences people report is tetany — involuntary muscle cramps, tingling in the hands and face, or spasms in the arms and legs. Though it can feel alarming, there’s a clear physiological explanation.
How Breathwork Changes Blood Chemistry
When you intentionally breathe faster and deeper than your body needs — a form of hyperventilation — you exhale large amounts of carbon dioxide (CO₂). Because CO₂ is acidic, losing too much of it tips the blood toward alkalinity, a state called respiratory alkalosis.[1], [2], [3], [7], [8]
The Chemistry Behind It
In the bloodstream, CO₂ dissolves and reacts with water to form carbonic acid (H₂CO₃), which then dissociates into hydrogen ions (H⁺) and bicarbonate (HCO₃⁻):
CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ + HCO₃⁻
When you hyperventilate, CO₂ levels fall. The reaction shifts leftward, reducing free hydrogen ions in the blood. Fewer H⁺ ions mean the blood becomes more alkaline (higher pH). This chemical shift triggers downstream effects on calcium, nerves, and circulation. Hyperventilation also constricts cerebral blood vessels, reducing blood flow to the brain and contributing to dizziness or fainting.[1], [2], [3], [7], [8]
Calcium and Nerve Excitability
In the bloodstream, calcium exists in three forms: ionized (free, ~45%), protein-bound mainly to albumin (40%), and complexed with small anions like phosphate or citrate (15%). Only the ionized form is biologically active in nerve and muscle signaling.
Albumin carries several negatively charged sites that can bind positively charged ions like calcium (Ca²⁺) and hydrogen (H⁺).
- At normal pH (~7.4), a balance exists between Ca²⁺ bound to albumin and free ionized Ca²⁺.
- When pH rises (alkalosis), fewer hydrogen ions are available to occupy those negative albumin sites.
- The albumin then binds more calcium, forming additional Ca–albumin complexes.
- This reduces free (ionized) calcium, even though total calcium remains unchanged.
When blood becomes more alkaline:
- Fewer hydrogen ions (H⁺) are available to compete with calcium for albumin’s negatively charged binding sites.
- Albumin binds more calcium, forming extra calcium–albumin complexes.
- Free ionized calcium in the blood falls, even though total calcium is unchanged.[4], [5], [6], [15]
Why does this matter? Ionized calcium normally stabilizes nerve membranes by making voltage-gated sodium channels harder to open. When ionized calcium drops, those channels become easier to trigger. Nerves fire more readily — creating the basis for tetany.[4], [5], [6], [15]
In short: higher pH → less H⁺ → more Ca²⁺ bound to albumin → less free Ca²⁺ → nerves become hyperexcitable.[4], [5], [6], [15]
From Chemistry to Experience: Why Tetany Feels the Way It Does
This nerve hyperexcitability manifests as:[9], [10], [11]
- Tingling and numbness (paresthesias), especially around the lips, hands, and feet.
- Carpopedal spasms — hands curling into claw-like positions.
- Facial twitching or muscle cramps.
- Occasionally, throat tightness or spasms (laryngospasm).
In breathwork circles, these sensations are sometimes reframed as part of the release process, though physiologically, they’re a direct outcome of alkalosis-induced hypocalcemia.
Is It Dangerous?
For healthy people, this state is usually temporary and harmless. Once normal breathing resumes, CO₂ levels rise, blood pH balances, and ionized calcium returns to baseline. The cramps and tingling fade within minutes.[4], [5], [6], [9], [10], [11]
Potential risks include:
- Fainting from reduced cerebral blood flow due to vasoconstriction.[1], [2], [3], [7], [8]
- Arrhythmias in people with heart conditions.
- Seizures in those predisposed.
- Rarely, laryngospasm (airway spasm), which can be serious.[3], [9]
That’s why structured breathwork practices emphasize safe settings: lying down, guided facilitation, and medical screening for participants with health conditions.
Between Physiology and Mystery
While the biochemistry explains how, it doesn’t capture what it feels like. Many practitioners describe the sensations in these breathwork states as energy release — the nervous system stretching, pressure giving way to expansion, the body discharging what no longer serves.
Modern research supports the idea that breath-control practices can induce altered states of consciousness (ASCs) and engage brain networks tied to self-perception, attention, emotion, and interoception:
- Controlled or rapid breathing can evoke subjective “mystical-quality” experiences and measurable changes in neural complexity.[12]
- Surveys of yoga, meditation, and breath-based practices show that many participants experience non-ordinary states of consciousness, sometimes challenging but often transformative.[13]
- Physiological studies show breathwork alters brain network connectivity, improves mood, and enhances body awareness.[14]
In these spaces, the scientific and spiritual frames converge: the same physiological shifts in CO₂, pH, calcium, and neural excitability that cause tingling and spasms can also unlock profound psychological or spiritual experiences. Interpreting these sensations as symbolic or energetic doesn’t contradict the biology — it reflects the body’s innate dialogue between matter and meaning.[12], [13], [14]
The Takeaway
Tetany during breathwork sits at the intersection of science and spirit. Biologically, it’s a dance of CO₂, pH, and calcium. Experientially, it can feel like the body cracking open, releasing what no longer serves, and touching the edge of the mystical.
To breathe this way is to play with thresholds — of chemistry, of consciousness, of what it means to be human. And sometimes, those thresholds curl your hands into little lobster claws.
