Mechanisms of “Buccal Pumping” (“Lung Packing”) and Its Pulmonary Effects

Authors: H. Örnhagen, E. Schagatay, J. Andersson, E. Bergsten, P. Gustafsson, S. Sandström
DOI / Source: https://www.researchgate.net/publication/293143960_Mechanisms_of_buccal_pumping_lung_packing_and_its_pulmonary_effects
Date: 12 August 1998

Reading level: Intermediate

Why This Matters for Freedivers

Lung packing can meaningfully increase your lung volume and may (in theory) increase “maximum possible depth,” but this paper makes the risk side very clear: packing creates very high pressures and overinflation at the surface, which can raise the chance of lung injury if it’s done aggressively or combined with other stressors. If you pack, the message is: treat it like a powerful tool that needs careful progression and conservative habits—not a casual “extra step” before every dive.

Synopsis

“Lung packing” (also called buccal pumping or glossopharyngeal insufflation) is a technique where divers use the mouth, tongue, throat, and larynx like a pump to push extra air into the lungs after a normal full inhale. This manuscript breaks down how the pumping cycle works and what it does to the lungs and chest.

The authors studied three experienced breath-hold divers who already knew how to pack. They observed the packing movements with imaging of the throat/mouth (showing the sequence of sealing with the lips/soft palate, moving the tongue, briefly opening/closing the glottis, and “squeezing” air into the lungs in repeated small cycles). Trained divers could perform roughly 1–2 “chips” (packing cycles) per second.

They then measured lung volumes and pressures before and after packing. Packing increased vital capacity in all three divers, adding roughly half a litre up to around 1.7 litres of extra air, with individual “chip” volumes reported up to ~168 mL. Alongside the added volume, the relaxed airway pressures recorded at given lung volumes were higher after packing, showing that packing can place the lung–chest system under unusually high pressure and stretch.

One practical question the paper tackles is “where does the extra air go?” Chest imaging did not show obvious dangerous trapped air (like mediastinal air) in these subjects, but the diaphragm sat lower at maximum inflation after packing—consistent with a more expanded thorax/lung system.

The discussion links these findings to depth potential and risk. More starting lung volume can increase the ratio of total lung capacity to residual volume, which could delay when the lungs compress toward their minimum volume at depth—potentially allowing deeper dives in theory. But the authors emphasize the trade-off: packing at the surface can create overinflation and high transpulmonary pressures, which increases the risk of lung barotrauma and possibly lung rupture—especially if the chest wall doesn’t provide enough support or if the diver strains against a closed glottis. They also highlight that reported “burst pressures” for lungs are in a range that makes the risk non-trivial, and they warn against overlooking this in the push for performance.

Overall, it’s a clear, mechanics-focused explanation: packing can increase lung volume significantly, but it can also push the lungs into a higher-risk pressure/stretch zone—so technique, restraint, and safety context matter.

Abstract

This manuscript describes how breath-hold divers perform buccal pumping (“lung packing”) and reports its effects on lung volume and airway pressure in three experienced divers. Imaging observations outline the sequence of mouth–throat movements used to transfer small boluses of air into the lungs (“chips”), and physiological measurements show that packing increases vital capacity and raises relaxed airway pressures at comparable lung volumes. The discussion considers how added lung volume could influence theoretical depth potential while emphasizing that packing performed at the surface creates overinflation and high intrathoracic/transpulmonary pressures, which may increase the risk of pulmonary barotrauma and lung rupture.

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