Which factor contributes to a higher incidence of decompression sickness at altitude?

Which factor contributes to a higher incidence of decompression sickness at altitude?

• A. Increased time at altitude contributes to a greater incidence of DCS.
• B. DCS only occurs after diving, not altitude.
• C. Hyperbaric exposure reduces risk of DCS.
• D. Higher temperatures at altitude increase elimination of dissolved gases.

Answer: (A)

Decompression sickness risk at altitude grows with the amount of time spent at reduced ambient pressure. When body tissues are exposed to lower pressure, dissolved inert gas (mostly nitrogen) tends to come out of solution. If the exposure is prolonged, more gas can form bubbles in tissues and blood, increasing the likelihood and severity of DCS. So, longer time at altitude means more opportunity for bubble formation and thus a higher incidence of DCS. The other statements aren’t the primary driver here: DCS can occur without a dive, simply from ascent to and time at altitude; hyperbaric conditions (higher pressure) would reduce, not increase, DCS risk by suppressing bubble formation; and temperatures at altitude do not reliably promote gas elimination in a way that would negate the risk—temperature effects on gas solubility don’t support that choice as a controlling factor.

Decompression sickness risk at altitude grows with the amount of time spent at reduced ambient pressure. When body tissues are exposed to lower pressure, dissolved inert gas (mostly nitrogen) tends to come out of solution. If the exposure is prolonged, more gas can form bubbles in tissues and blood, increasing the likelihood and severity of DCS. So, longer time at altitude means more opportunity for bubble formation and thus a higher incidence of DCS.

The other statements aren’t the primary driver here: DCS can occur without a dive, simply from ascent to and time at altitude; hyperbaric conditions (higher pressure) would reduce, not increase, DCS risk by suppressing bubble formation; and temperatures at altitude do not reliably promote gas elimination in a way that would negate the risk—temperature effects on gas solubility don’t support that choice as a controlling factor.