What it is
Decompression sickness ("the bends") strikes when dissolved nitrogen forms bubbles in blood and tissue after too-rapid ascent from depth. Symptoms range from joint pain and fatigue to numbness, weakness, and paralysis.
How hyperbaric oxygen helps
Recompression is the treatment — this is where hyperbaric medicine was born. Pressure shrinks the nitrogen bubbles; breathing pure oxygen creates the gradient that washes nitrogen out of the body while oxygenating injured tissue, especially the spinal cord.
What treatment looks like
Standard care follows US Navy Treatment Table 6: about five hours at up to 2.8 ATA with scheduled air breaks. Most divers need one to a few sessions; severe neurological cases may need more.
- Diver emergency? Call 911 and the DAN hotline (+1-919-684-9111) — they'll route you to the nearest chamber.
- Breathe oxygen if available and stay flat while awaiting transport.
- Never attempt in-water recompression.
The evidence, honestly
Grade A — Strong Evidence
Supported by randomized trials and/or decades of consistent clinical results.
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Hyperbaric treatment for decompression sickness: current recommendations
Undersea & Hyperbaric Medicine · 2019 · review
Reviews the physiological basis and established use of recompression (e.g., US Navy Treatment Table 6) as definitive therapy for decompression sickness, the historical foundation of hyperbaric medicine.
Common questions
How soon after diving can symptoms appear?
Usually within 6 hours, but up to 24–48 hours after surfacing. Any suspicious symptom after diving deserves a call to DAN — flying can make it worse, so get checked before boarding.
Can I fly after treatment?
Not immediately. Your treating physician will give you a specific waiting period, typically at least 72 hours after symptoms resolve.
Educational content, not medical advice — see our medical disclaimer. *Medicare coverage requires meeting clinical criteria; we verify yours for free. Last medically reviewed July 2026 by Dr. David Greene, MD.