To prevent air embolism, a diver should

• A. Breathe normally at all times during ascent and never hold his/her breath
• B. Hold breath during ascent to stabilize buoyancy
• C. Exhale only through the nose during ascent
• D. Breathe rapidly to gas exchange

Answer: (A)

During ascent, the pressure around you drops, causing any gas in the lungs to expand. If you hold your breath, that expanding air has nowhere to escape and can overinflate the lungs, potentially sending air into the bloodstream as an embolism. Breathing normally throughout the ascent lets the lungs vent the expanding gas safely and maintains a stable buoyancy, dramatically reducing the risk of this dangerous event.

Holding breath during ascent directly creates the risk you’re trying to avoid. Exhaling only through the nose doesn’t provide the continuous, natural exhalation through the mouth needed to manage lung volume as you rise, and rapid breathing doesn’t solve the fundamental issue of gas expansion and can worsen buoyancy control or cause other problems.