There is more to humming than producing a tune to pass the time or self-soothe. Several studies have explored its mechanism and have found specific biological effects that are linked to physiological and psychophysiological health benefits. Specifically, when someone hums, several things happen not only in the nasal cavity but throughout the body.
Two Main Health Benefits of Humming: Harnessing Nitric Oxide and Vagal Tone for Optimal Health
Increases Nasal Nitric Oxide to Widen Airways and Pulmonary Blood Vessels and Help Fight Off Pathogens Entering the Upper Respiratory Tract
Humming turns your sinuses into a natural pharmacy. The simple act of humming dramatically increases the release of a potent gas that can inhibit the growth of pathogens and naturally widens your airways and pulmonary blood vessels.
Note that the primary and most studied physiological benefit of humming centers on its effect on the paranasal sinuses and the release of nitric oxide. Swedish physicians and professors Eddie Weitzberg and Jon O. Lundberg first hypothesized in 2002 that oscillating airflow produced by humming would enhance sinus ventilation and nitric oxide levels.
The paranasal sinuses are air-filled cavities surrounding the nasal passages. They are the primary natural reservoir of nitric oxide. This nitric oxide, when inhaled, causes the blood vessels in the lungs to relax. The pulmonary vasodilation effect reduces vascular resistance and optimizes blood flow to facilitate a more efficient transfer of oxygen into the bloodstream.
Nitric oxide also acts as a primary neurotransmitter of the bronchodilator nerves in the human airways, which signals the smooth muscles that wrap the bronchial tubes to relax. When it slips across the muscle cell wall, it binds to the sGC enzyme. This enzyme then produces the calming chemical molecule cGMP, which relaxes and opens up airway muscles.
Moreover, the nitric oxide produced in the sinuses serves as a first line of defense in the upper respiratory tract. It is a potent antiviral, antibacterial, and antifungal agent that inhibits the growth of inhaled pathogens before they reach the lower respiratory tract. It also stimulates and maintains the proper beating of the cilia to enhance mucociliary clearance.
The 2002 study of Weitzberg and Lundberg involved comparing nitric oxide levels from humming exhalation and quiet exhalation in 10 healthy subjects. Results revealed that humming produced 2818 nanoliters of nitric oxide output per minute. This was about 15-fold higher than the 189 nanoliters nitric oxide output per minute produced through quiet exhalation.
In the same paper, the researchers explained that the oscillating pressure or pulsating sound waves from the humming sound force a rapid exchange of air between the nasal cavity and the nitric oxide-rich sinuses. The vibration essentially enhances the gas exchange in the upper respiratory tract. This leads to a rapid washout of accumulated nitric oxide.
Measuring nasal nitric oxide levels during humming can also be a potential noninvasive test for assessing the openness of the sinus passages. This is because humming in healthy individuals provides a large nitric oxide peak, while those with conditions like severe nasal polyposis or allergic rhinitis have reduced or zero nitric oxide peak when humming.
Regulates the Parasympathetic Nervous System By Stimulating the Vagus Nerve to Lower Stress and Heart Rate, and Increase Heart Rate Variability
Humming physically stimulates a nerve long considered the master controller of the rest and digest mode of the body. It regulates the nerves to result in a measurable reduction in heart rate and stress level while boosting heart rate variability.
Bhramari pranayama, also known as Humming Bee Breath, is a calming yoga breathing technique where an individual inhales deeply through the nose and exhales slowly through the nose while making a low-pitched or bee-like humming sound. This practice is a calming exercise performed to reduce stress, relieve tension, boost concentration, and control blood pressure.
A pilot study published in 2023, which was led by S. Shah and with G. Trivedi as the first author, examined the calming effects of simple Bhramari pranayama and, by extension, humming. The investigation involved assessing the heart rate variability or HRV parameters of 23 participants who underwent humming, physical activity, emotional stress, and sleep.
Results indicate that humming, via simple Bhramari pranayama, produced the lowest stress index compared to physical activity and sleep. The practice significantly shifts the body toward the parasympathetic nervous system, as confirmed by an increase in HRV and a decrease in heart rate. Note that both HRV and heart rate are indicators of improved vagal tone.
A more recent study by Minjung Woo and Teri Kim showed similar results. Their research centered on comparing humming and slow-paced breathing in 16 healthy participants. Both were found to significantly increase HRV. The researchers further concluded that humming is a viable alternative to slow-paced breathing for enhancing both HRV and autonomic regulation.
The calming benefits of humming come from how it stimulates the Vagus nerve. The Vagus nerve is a cranial nerve and the primary nerve of the parasympathetic nervous system, which governs the rest and digest and feed and breed functions, that runs from the brainstem through the neck and chest down to the abdomen to connect the heart, lungs, and digestive tract.
Nevertheless, during humming, the deep and resonant sound and physical vibration produced in the throat, larynx, and chest physically stimulate the branches of the Vagus Nerve located in these areas. The stimulation sends a direct signal from the parasympathetic nervous system to the brain to override the fight or flight mode of the sympathetic nervous system.
In addition, because humming results in the release of nitric oxide from the paranasal sinuses, and since nitric oxide is a bronchodilator and pulmonary vasodilator, the effects are better oxygen absorption, a slower or more regulated heart rate, and lower blood pressure. Note that both of these contribute to the overall state of relaxation and a regulated nervous system.
FURTHER READINGS AND REFERENCES
- Lundberg, J. O., Maniscalo, M., Sofia, M., Lundblad, L., and Weitzberg, E. 2003. “Humming, Nitric Oxide, and Paranasal Sinus Obstruction.” JAMA. 289(3): 302. DOI: 1001/jama.289.3.302-b
- Trivedi, G., Sharma, K., Saboo, B., Kathirvel, S., Konat, A., Zapadia, V., Prajapati, P. J., Benani, U., Patel, K., and Shah, S. 2023. “Humming (Simple Bhramari Pranayama) as a Stress Buster: A Holter-Based Study to Analyze Heart Rate Variability (HRV) Parameters During Bhramari, Physical Activity, Emotional Stress, and Sleep.” Cureus. DOI: 7759/cureus.37527
- Weitzberg, E. and Lundberg, J. O. N. 2002. “Humming Greatly Increases Nasal Nitric Oxide.” American Journal of Respiratory and Critical Care Medicine. 166(2): 144-145. DOI: 1164/rccm.200202-138bc
- Woo, M. and Kim, T. 2025. “Effects of Slow-Paced Breathing and Humming Breathing on Heart Rate Variability and Affect: A Pilot Investigation.” Physiology & Behavior. 299: 114972. DOI: 1016/j.physbeh.2025.114972