Conch shell blowing lowers apnea events during REM sleep

By Dr. Sanchari Sinha Dutta, Ph.D.Reviewed by Lauren HardakerAug 13 2025

In a new trial, a centuries-old yogic breathing practice using a conch shell showed measurable benefits for sleep apnea, offering a simple, non-invasive alternative to conventional treatments.

Study: Efficacy of blowing shankh on moderate sleep apnea: a randomised control trial. Image credit: Eivaisla/Shutterstock.com

A clinical trial conducted by researchers from the Eternal Heart Care Centre and Research Institute, India, demonstrated the therapeutic efficacy of shankh blowing in relieving obstructive sleep apnea symptoms through respiratory muscle training. The trial report is published in ERJ Open Research.  

Background

Obstructive sleep apnea is a common sleep disorder, characterized by repeated episodes of partial or complete upper respiratory obstruction during sleep. The condition often leads to intermittent hypoxia and interrupted sleep. Continuous positive airway pressure is the gold standard treatment for obstructive sleep apnea. In this treatment, a machine continuously supplies air to the respiratory tract through a mask to prevent airway collapse during sleep.

Despite satisfactory therapeutic efficacy, patients’ acceptance and adherence to continuous positive airway pressure therapy are low, causing a significant barrier to effective management of obstructive sleep apnea. Moreover, this therapy is not recommended for less symptomatic patients, particularly those with mild or moderate obstructive sleep apnea.

For this group of less symptomatic patients, mandibular advancement devices, weight loss, positional therapy, and surgery, are alternative treatment options with variable efficacy. Upper respiratory muscle training through playing wind musical instruments is considered a helpful approach for managing moderate obstructive sleep apnea.

Given the proven benefits of respiratory muscle training, researchers at the Eternal Heart Care Centre and Research Institute conducted a randomized controlled trial to investigate the therapeutic efficacy of shankh blowing in improving moderate obstructive sleep apnea symptoms.

Shankh blowing is a yogic breathing exercise involving forceful exhalation through a conch shell. It is expected to strengthen respiratory muscles and improve lung function. The shankh, especially the Indian Shankh, has a unique spiraling structure and an inner cavity. When blown, it produces a resonating sound believed to hold healing properties.

Trial design

The study screened 62 individuals, of whom 38 were randomized (19 to each group). The trial enrolled 30 individuals with moderate obstructive sleep apnea. The participants were randomly assigned to the intervention group and the control group.

The intervention group participants were trained to blow the shankh and were asked to perform it at home for a minimum of 15 minutes, five days per week, for six months. Participants attended monthly follow-up visits, where the technique was reviewed and compliance logs (≥80% sessions) were recorded. The control group participants followed the same schedule to perform a sham procedure involving deep breathing exercises.

At the end of the trial period (after six months), all participants were evaluated for daytime sleepiness, sleep quality, and sleep apnea severity.

Key findings

The trial findings revealed that shankh blowing, performed for six months, is significantly more effective than deep breathing exercises (sham procedure) in reducing daytime sleepiness, improving sleep quality, and ameliorating sleep apnea severity.

The participants who performed shankh blowing for six months experienced significant reductions in body mass index (a measure of overweight or obesity). In contrast, the control group participants experienced a significant increase. For example, BMI decreased by 0.33 kg/m² in the intervention groups compared to an increase of 0.53 kg/m² in controls.

Daytime sleepiness scores (Epworth Sleepiness Scale) decreased by 5.0 points in the intervention group (34% reduction) versus 0.3 points in the control group, while sleep quality score (Pittsburgh Sleep Quality Index) improved by -1.8 points in the intervention group compared to worsening of +1.3 points in controls.

Overall, apnea-hypopnea index (AHI) fell by 4.4 events/h in the intervention group compared to an increase of 1.2 events/h in controls, leading to a between-group difference of -5.62 events/h. Significant reductions were observed for non-rapid eye movement (NREM) AHI (-22.8%) and rapid eye movement (REM) AHI (-21.8%) in the intervention group, whereas controls showed non-significant increases.

Significance

The trial highlights the therapeutic potential of blowing shankh in adult individuals with moderate obstructive sleep apnea. According to the findings, six months of shankh blowing leads to a 34% reduction in daytime sleepiness. The observed 21.8% reduction in apnea events during REM sleep holds clinical significance, as REM-related respiratory events often correlate with greater cardiovascular and neurocognitive risks.

The trial finds a significant improvement in oxygen saturation at night among participants who performed six-month shankh blowing (+7.1% in the lowest nocturnal SpO₂ vs. -1.7% in controls). This measure was not a predefined endpoint; the authors note it warrants further study. This observation also holds clinical significance, as nocturnal desaturation is known to increase cardiovascular risk in individuals with obstructive sleep apnea.

The researchers suggest that the observed improvements can be attributed to respiratory muscle training through shankh blowing. This interpretation is further supported by the observed reduction in neck circumference, suggesting upper airway remodeling through shankh blowing.

The current trial findings, together with previous research findings, suggest that training and strengthening oropharyngeal and thoracic muscles through blowing shankh or playing specific musical instruments may reduce the risk of upper airway collapse during sleep, leading to improvement of sleep-related outcomes and reduction of sleep apnea severity.

The trial provides a novel intervention to manage obstructive sleep apnea-related outcomes. However, the open-label trial design may introduce performance bias, where participants' and researchers' knowledge of the treatment assignment may influence their behavior and responses. Although monthly reviews were conducted, the authors acknowledge that the possible influence of other exercises or activities on the observed improvements cannot be ruled out. The authors also note that the relatively small sample size, single-center setting, and per-protocol analysis may limit generalizability and could overestimate the effect sizes.

The trial did not assess comprehensive oxygenation parameters such as the oxygen desaturation index or the duration of desaturation events. Future trials should include these parameters to more conclusively understand the physiological impact and clinical significance of shankh blowing. However, this proof-of-concept trial provides a foundation for future research to evaluate the applicability of blowing shankh as a therapeutic intervention for individuals with moderate obstructive sleep apnea.

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