Glossary

Key terms used across Vayu, breathwork science, and nervous system regulation.

4-7-8 Breathing

A pattern developed by Dr. Andrew Weil: inhale 4s, hold 7s, exhale 8s. The extended exhale strongly activates the parasympathetic nervous system.

Autonomic Nervous System (ANS)

The part of the nervous system that controls involuntary functions like heart rate, digestion, and breathing. Consists of sympathetic and parasympathetic branches.

Bhastrika

A pranayama technique involving rapid, forceful inhales and exhales. Energizing and detoxifying. Also called 'bellows breath.'

Box Breathing

A technique with equal-duration inhale, hold, exhale, hold (typically 4-4-4-4 seconds). Used by Navy SEALs for focus and calm under pressure.

Coherence Breathing

Breathing at approximately 5-6 breaths per minute to maximize HRV and synchronize heart rhythm with breath rhythm. Also called resonance frequency breathing.

Haptic Guidance

Vayu's core innovation: the smartwatch vibrates in rhythm with the breathing pattern, so users feel when to inhale, hold, and exhale — no screen or audio needed.

HRV (Heart Rate Variability)

The variation in time between consecutive heartbeats. Higher HRV generally indicates better cardiovascular fitness and stress resilience. Vayu tracks HRV during breathing sessions via smartwatch sensors.

Kapalbhati

A pranayama cleansing technique with passive inhales and active, sharp exhales. Stimulates digestion and mental clarity.

Nadi Shodhana

Alternate nostril breathing. Balances the left and right hemispheres of the brain, reduces anxiety, and improves respiratory function.

Parasympathetic Nervous System

The 'rest and digest' branch of the autonomic nervous system. Activated by slow, deep breathing — especially extended exhales. Counteracts the stress (sympathetic) response.

Physiological Sigh

A double inhale through the nose followed by a long exhale through the mouth. Discovered by Stanford researchers as the fastest real-time stress reduction technique.

Pranayama

The ancient yogic practice of breath control. 'Prana' means life force, 'yama' means control. Encompasses dozens of techniques refined over thousands of years.

Respiratory Sinus Arrhythmia (RSA)

The natural variation in heart rate that occurs with breathing — heart rate increases on inhale and decreases on exhale. A marker of vagal tone and cardiovascular health.

Sympathetic Nervous System

The 'fight or flight' branch of the autonomic nervous system. Triggers stress hormones, elevated heart rate, and shallow breathing. Breathwork helps downregulate this response.

Ujjayi

Ocean breath — breathing through a slightly constricted throat, producing a gentle ocean-wave sound. Used in yoga for concentration and inner heat.

Vagus Nerve

The longest cranial nerve, connecting the brain to the gut. Key mediator of the parasympathetic response. Stimulated by slow breathing, humming, and cold exposure.