Bhramari: Humming Bee Breath, Nitric Oxide, and Vagal Stimulation

The Simplest Pranayama with the Most Surprising Science

Bhramari — named for the Indian black bee (bhramara) — is a pranayama technique in which the practitioner inhales through the nose and exhales while producing a steady humming sound with the mouth closed. It is one of the simplest breath practices to learn, one of the safest to practice, and one of the most scientifically interesting.

The Hatha Yoga Pradipika describes Bhramari as a practice that produces “a kind of ecstasy in the mind of the yogin” (2.68). Modern research suggests the ecstasy may be less mystical and more biochemical than the text implies — but no less real.

The three primary mechanisms of Bhramari are: (1) massive nitric oxide production through nasal humming, (2) vagal nerve stimulation through laryngeal vibration, and (3) vibroacoustic effects on the cranial structures and brain. Each mechanism alone would make Bhramari clinically interesting. Together, they make it one of the most underutilized therapeutic tools in the pranayama repertoire.

Mechanism 1: Nitric Oxide Production

The most surprising discovery about Bhramari comes from a field that has nothing to do with yoga. Weitzberg and Lundberg (2002), publishing in the American Journal of Respiratory and Critical Care Medicine, found that humming during nasal exhalation increases nitric oxide (NO) output from the paranasal sinuses by 15-fold compared to quiet nasal exhalation. Fifteen-fold. This is not a marginal increase — it is an order of magnitude shift.

Nitric oxide, produced by the nasal epithelium and paranasal sinus epithelium, serves multiple functions:

Antimicrobial: NO is directly toxic to bacteria, viruses, and fungi. The paranasal sinuses are essentially NO generators, and the gas serves as a first-line defense against airborne pathogens. Chronic sinusitis is associated with reduced sinus NO production (Lundberg, 2008). Humming may restore this natural antimicrobial mechanism.

Vasodilator: NO is the primary vasodilator in the cardiovascular system (the discovery of NO’s vascular effects earned Furchgott, Ignarro, and Murad the Nobel Prize in 1998). Inhaled nasally, NO dilates pulmonary blood vessels, improving ventilation-perfusion matching in the lungs — the same principle behind inhaled NO therapy for pulmonary hypertension in neonates.

Bronchodilator: NO relaxes bronchial smooth muscle, promoting airway opening. This has obvious implications for asthma and COPD.

Cognitive enhancement: NO serves as a neurotransmitter and neuromodulator in the brain, involved in synaptic plasticity, memory consolidation, and cerebral blood flow regulation. Increased NO delivery to the brain through nasal humming may support cognitive function.

The mechanism of increased NO during humming is vibroacoustic: the sound vibrations oscillate the air in the paranasal sinuses (maxillary, frontal, ethmoid, sphenoid), creating turbulent flow that pulls NO from the sinus epithelium into the airstream. In quiet breathing, air flows laminar through the nasal passages, bypassing the sinuses with minimal gas exchange. During humming, the vibrations create oscillating pressure waves that ventilate the sinuses — essentially shaking the NO loose.

Mechanism 2: Vagal Stimulation

The humming sound produced during Bhramari requires sustained engagement of the laryngeal muscles — the same muscles involved in speaking, singing, and other vocalizations. These muscles are innervated by the vagus nerve, and their activation sends afferent signals to the brainstem’s dorsal motor nucleus and nucleus ambiguus, stimulating parasympathetic outflow.

Kuppusamy et al. (2016) studied Bhramari’s effects on autonomic function and found significant increases in parasympathetic markers (HF-HRV) and decreases in sympathetic markers (LF-HRV) during and after practice. Heart rate decreased, and participants reported subjective states of calm and well-being.

Pramanik et al. (2009) demonstrated that even five minutes of Bhramari produced significant reductions in heart rate, systolic blood pressure, and diastolic blood pressure, with the effects persisting for several minutes after cessation of the practice.

The vagal stimulation from Bhramari parallels the effects of clinical vagus nerve stimulation (VNS), an FDA-approved therapy for treatment-resistant epilepsy and depression. VNS uses an implanted electrode to stimulate the vagus nerve electronically. Bhramari achieves a similar (though less intense) stimulation through the natural engagement of vagally-innervated laryngeal muscles — no surgery required.

The connection to polyvagal theory is direct: humming activates the ventral vagal complex’s social engagement system. The muscles of the larynx, pharynx, and middle ear are all part of this system. Humming is a prosocial vocalization — it signals safety, contentment, and social availability (mothers hum to soothe infants). Bhramari practice literally activates the neural circuitry of social safety.

Mechanism 3: Vibroacoustic Effects

The vibrations produced during Bhramari are not confined to the larynx. They propagate through the bones of the skull, the sinuses, and the cranial cavity. The skull is an acoustic resonance chamber, and specific frequencies of humming produce resonance in specific cranial structures.

The fundamental frequency of humming (typically 100-500 Hz) falls within the range that produces cranial bone conduction — the transmission of vibration through the temporal, frontal, and sphenoid bones directly to the brain tissue and meninges beneath.

This vibroacoustic stimulation may affect:

The pituitary gland: Housed in the sella turcica of the sphenoid bone — a bone that forms the floor of the cranial cavity and the roof of the nasal cavity. Sphenoid vibration during humming may directly stimulate the pituitary through mechanical transduction. This is speculative but anatomically plausible.

The pineal gland: Located on the posterior aspect of the third ventricle. Some practitioners report visual phenomena (perception of light, colors) during prolonged Bhramari practice, which could relate to pineal stimulation. The traditional claim that Bhramari prepares for meditation and enhances pratyahara may involve pineal melatonin release.

Cerebrospinal fluid dynamics: The vibrations may affect CSF oscillation in the ventricular system and subarachnoid space, producing subtle changes in intracranial pressure dynamics.

Clinical Applications

Sinusitis

The 15-fold increase in sinus NO production during humming makes Bhramari a natural adjunct for sinus infections. The antimicrobial NO, combined with the mechanical ventilation of the sinuses by sound vibrations, addresses both the infectious and the stagnation components of sinusitis.

Protocol: 5-10 rounds of Bhramari, 3-4 times daily during acute sinusitis. Each round: inhale through the nose, exhale with humming until the breath is comfortably spent. Rest 2-3 breaths between rounds. Can be combined with Shanmukhi Mudra (closing the ears, eyes, and nostrils with the fingers) for enhanced vibratory effect, but this is optional.

Anxiety

Bhramari is one of the safest pranayama practices for anxious patients because:

• It requires no breath retention (which can trigger panic)
• It does not involve hyperventilation (which can trigger panic)
• The humming sound provides an external focus that interrupts rumination
• The vagal stimulation produces immediate parasympathetic activation
• The vibration in the skull is inherently soothing — humans instinctively hum to self-regulate (think of a nervous person humming to themselves)

Protocol: 5-10 rounds of Bhramari whenever anxiety arises. Can be practiced anywhere — the sound is quiet enough to do in a parked car, a bathroom stall, or an office with the door closed.

Insomnia

The parasympathetic activation and the potential melatonin-enhancing effects of cranial vibration make Bhramari an excellent pre-sleep practice.

Protocol: 10-15 rounds of Bhramari in bed, lying down, with eyes closed. The humming provides a focus that replaces racing thoughts. The vibration calms the nervous system. Many practitioners fall asleep during the practice.

Tinnitus

Counterintuitively, producing a controlled sound (humming) can provide relief from the uncontrolled sound perception of tinnitus. The mechanisms may include:

• Vagal activation reducing the hyperexcitability of the auditory cortex
• Sound masking (the humming provides a controlled auditory input that partially masks the tinnitus)
• Habituation training (the brain learns to categorize the humming as non-threatening, which may generalize to the tinnitus sound)
• NO-mediated improvement in cochlear blood flow (the cochlea is sensitive to vascular changes, and NO’s vasodilatory effects may improve microcirculation)

Protocol: 10 rounds of Bhramari, 2-3 times daily. Practice with Shanmukhi Mudra (ears closed with the tragus) to enhance internal awareness of the vibration. This is not a cure but a management tool that some tinnitus sufferers find helpful.

Hypertension

The combined effects of NO-mediated vasodilation, parasympathetic activation, and stress reduction make Bhramari a promising adjunct for hypertension management.

Pramanik et al. (2009) found significant blood pressure reductions after just five minutes of Bhramari. While the acute effects are transient, regular practice (twice daily) may produce sustained blood pressure improvements through chronic autonomic remodeling.

The Shanmukhi Mudra Enhancement

Traditional Bhramari is often practiced with Shanmukhi Mudra (“seal of the six gates”) — closing the ears with the thumbs, the eyes with the index fingers, the nostrils with the middle fingers (released for inhalation), and the mouth with the ring and little fingers.

This mudra:

• Amplifies the internal perception of vibration (closing the ears removes competing auditory input)
• Promotes pratyahara (closing the sensory gates intensifies inward focus)
• May enhance the cranial resonance effect (the pressure of the fingers on the cranial bones may modify vibration patterns)
• Intensifies the meditative quality of the practice

Integration with Functional Medicine

Bhramari’s NO production connects it to the functional medicine understanding of nitric oxide as a critical signaling molecule:

• Cardiovascular health: NO deficiency is implicated in hypertension, atherosclerosis, and endothelial dysfunction. Bhramari provides an endogenous NO-boosting practice.
• Immune function: NO’s antimicrobial properties support innate immune defense. Bhramari may support respiratory immune function during cold and flu season.
• Gut health: NO regulates gastrointestinal motility and mucosal blood flow. While nasal NO does not directly reach the gut, the systemic effects of increased NO inhalation (vasodilation, improved oxygenation) may support gut function indirectly. Additionally, the vagal activation from humming improves gut motility through parasympathetic innervation of the enteric nervous system.

Testable Hypotheses

1. Regular Bhramari practice (3 times daily for 8 weeks) will reduce the frequency and severity of acute sinusitis episodes compared to nasal saline irrigation alone.
2. Bhramari will produce measurable increases in exhaled nasal NO that correlate with the duration and intensity of the humming — dose-response relationship.
3. Bhramari practiced before sleep will improve sleep onset latency and increase salivary melatonin levels compared to silent breathing at the same rate.
4. The combination of Bhramari with Shanmukhi Mudra will produce greater parasympathetic activation (measured by HRV) than Bhramari alone, isolating the contribution of sensory gating.

References

• Kuppusamy, M., Kamaldeen, D., Pitani, R., Amaldas, J., & Shanmugam, P. (2016). Effects of Bhramari Pranayama on health — a systematic review. Journal of Traditional and Complementary Medicine, 8(1), 11-16.
• Lundberg, J. O. (2008). Nitric oxide and the paranasal sinuses. The Anatomical Record, 291(11), 1479-1484.
• Pramanik, T., Sharma, H. O., Mishra, S., Mishra, A., Prajapati, R., & Singh, S. (2009). Immediate effect of slow pace Bhastrika Pranayama on blood pressure and heart rate. Journal of Alternative and Complementary Medicine, 15(3), 293-295.
• Porges, S. W. (2011). The Polyvagal Theory. W. W. Norton.
• Weitzberg, E., & Lundberg, J. O. (2002). Humming greatly increases nasal nitric oxide. American Journal of Respiratory and Critical Care Medicine, 166(2), 144-145.