What can happen if a diver ascends too quickly?

When a diver ascends too quickly, one of the serious risks involved is the occurrence of a spontaneous embolism, commonly known as an air embolism. As a diver descends, they inhale air, which includes nitrogen. Under higher pressures, such as those experienced underwater, the nitrogen is absorbed into the body tissues. If the diver ascends too quickly, the rapid decrease in pressure can cause the nitrogen that was dissolved in the body to form bubbles.

These bubbles can enter the bloodstream and obstruct blood vessels, potentially leading to severe complications such as stroke or even death. This is a critical reason why divers are trained to adhere to safe ascent rates, typically no faster than 30 feet per minute, and to include safety stops during their ascent to allow for the gradual release of nitrogen from their bodies.

The other options do not accurately reflect the effects of a rapid ascent. Improving buoyancy, decreasing oxygen consumption, or requiring less surface time do not relate to the physiological consequences of rapid ascent and do not pose the same level of risk as an embolism does.