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SESK: Stuff Everyone Should Know · sesk.info/scuba-breath-hold-four-feet

After breathing from a tank, how shallow can a breath-hold ascent still hurt your lungs?

As shallow as 4 feet of seawater.

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  1. Only below 60 feet
  2. Only below 33 feet
  3. As shallow as 4 feet ✔

Why: Lung injury is about the change in pressure, not total depth. Even in a pool, holding a full breath of tank air on the way up can tear the tiny air sacs in your lungs.

Huh, didn't know that: DAN notes a sudden ascent from 15 feet can make lung air expand by about 50 percent.

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Even the shallow end has deep feelings about breath holding.
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References

Answer: As shallow as 4 feet. Lung injury is about the change in pressure, not total depth. Even in a pool, holding a full breath of tank air on the way up can tear the tiny air sacs in your lungs.

  1. DAN Alert Diver: Lung-Expansion Injuries dan.org/alert-diver/article/lung-expansion-injuries
    a breathhold ascent after inhaling from a scuba tank from a depth as shallow as 4 fsw may be sufficient to tear alveolar sacs
    Checked 2026-10-12.

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