Lung Expansion Injuries: Prevention Strategies for San Diego Deep Divers

Lung expansion injuries—medically known as pulmonary barotrauma—are among the most serious risks in freediving. For San Diego divers exploring the reefs off La Jolla, the kelp forests near Point Loma, and the deeper channels of the Pacific, understanding pressure dynamics and prevention protocols isn’t optional. It’s survival.

What Happens at Depth

As you descend, water pressure increases by 1 atmosphere (14.7 psi) every 33 feet. Your lungs compress proportionally. The critical danger emerges during ascent: if you hold your breath while rising, the air in your lungs expands. At shallow depths—particularly the last 33 feet—this expansion accelerates. If your lungs can’t release that expanding air, pressure builds internally, potentially rupturing lung tissue, forcing air into the bloodstream (arterial gas embolism), or causing pneumothorax (collapsed lung).

This isn’t theoretical risk in San Diego. Our local dive sites range from shallow kelp beds at 30 feet to deep reefs beyond 100 feet. The Coronado Islands, Bird Rock, and the kelp forests near Ocean Beach all attract ambitious divers. Depth-related injuries happen fast and can be fatal.

The Golden Rule: Never Hold Your Breath

This is non-negotiable. The moment you descend on a breath-hold, you’re managing a finite volume of air. Ascend slowly and continuously exhale—even if you feel the urge to hold on for “just a bit more” surface time.

Many accidents occur in shallow water because divers underestimate expansion ratios. A diver at 66 feet (2 atmospheres) ascending to the surface experiences a 100% volume increase in their lungs. At 33 feet (1.5 atmospheres) ascending to the surface, expansion is 50%. At 16 feet, it’s 33%. The shallower you are, the faster expansion occurs. Never skip the final ascent breathing protocol.

Safe Descent and Bottom Time

Equalization is prevention. Start equalizing at the surface before you submerge. Use the Frenzel maneuver or Valsalva technique every few feet on descent. If you can’t equalize comfortably, stop. Forcing descent against pressure builds sinus and ear injuries that impair judgment and increase risk.

In San Diego’s kelp forests, visibility and current can tempt extended bottom time. Resist it. Plan conservative bottom times based on your lung volume and fitness level. A good rule: if you’re a 170-lb diver with average lung capacity (~6 liters), your comfortable depth range is 60–80 feet for recreational freediving. Beyond that, you’re entering technical territory and need advanced training.

Use the 80/20 rule: Consume only 80% of your available oxygen during the dive. Reserve 20% for ascent and safety margins. This buffer prevents shallow-water blackout during final ascent—a leading cause of freediving fatalities in Southern California.

Breathing Protocols Before and After

Pre-dive breathing isn’t about hyperventilation. Hyperventilation depletes CO₂, suppressing your body’s urge to breathe and masking hypoxia—the silent killer in freediving. Instead, practice 3–5 minutes of calm, measured breathing (4-second inhale, 4-second exhale) to relax and oxygenate naturally.

Post-dive, resume normal breathing immediately. Don’t hold your breath after surfacing. Your lungs are fully expanded; any pressure difference now works against you. Breathe freely, recover, and wait at least 3 minutes between dives.

Training and Local Knowledge

San Diego has excellent freediving instruction through AIDA and ISSA-certified schools. Before diving La Jolla Cove, the Coronado Islands, or Point Loma, take a level-appropriate course. Instructors teach not just technique but local conditions: currents, thermoclines, seasonal kelp density, and safe ascent corridors.

Respect seasonal changes. Winter brings colder water and stronger currents; summer offers calmer conditions and better visibility. Know the tide cycles—slack water at Sunset Cliffs or the Kelp Forests is safer than ripping current.

Equipment and Buddy Systems

Dive with a trained partner using a buddy line in low-visibility kelp forests. Carry a surface marker buoy (SMB) and signal your position. Know your dive computer or depth gauge limits. Many San Diego freediving accidents involve divers pushing beyond their training depth or diving alone.

The Bottom Line

Lung expansion injuries are preventable. Equalize properly, never hold your breath on ascent, plan conservative bottom times, and train with certified instructors familiar with San Diego conditions. The reefs and kelp forests will still be there if you take an extra dive to build skills safely.

Track your dives, monitor conditions, and stay within your limits. Download the Element app to check water temperature, visibility, and swell forecasts before heading to La Jolla, Point Loma, or the Coronado Islands—conditions change fast, and local data keeps you diving smart.