Double inhale or the “physiological sigh” technic

🫁 Exact Term

Physiological Sigh (sometimes called “double inhale sigh” or “cyclic physiological sigh”).

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🧬 Mechanism

• Structure: Two quick inhales through the nose → one long exhale through the mouth.
  • Inhale 1: normal depth.
  • Inhale 2: a short, sharp top-off.
  • Exhale: prolonged and complete.
• Function: This mimics a reflexive breathing pattern first described in Loewenstein & Carmichael (1946) and Yackle et al. (2017) — spontaneous double-inhalation sighs that mammals use to reinflate collapsed alveoli and reset CO₂/O₂ balance.
• Neural Circuitry: The preBötzinger complex in the medulla (a respiratory rhythm generator) contains specific neurons co-expressing NMB (neuromedin B) and CGRP, which coordinate this sigh reflex. Huberman’s lab and collaborators extended this into behavioral stress regulation research, showing its impact on parasympathetic tone and heart-rate variability.

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🧠 Huberman’s Contribution (c. 2020)

• Huberman and colleagues did not invent the physiological sigh; rather, they adapted it into a controlled, repeatable technique for emotion regulation and autonomic balance.
• His lab’s work and podcasts popularized it as the most efficient single-breath cycle for acute stress downregulation, corroborated by ongoing Stanford-affiliated studies comparing it to box breathing, cyclic hyperventilation, etc.