SDI Open Water Scuba Diver 2025 – 400 Free Practice Questions to Pass the Exam

When ascending from depth, the pressure surrounding your body decreases. As you ascend, the nitrogen that has been absorbed into your body under high pressure can begin to come out of solution if the ascent is too rapid. This is due to the reduced pressure allowing nitrogen gas to expand and form bubbles in the tissues and bloodstream. These bubbles can lead to decompression sickness, commonly known as "the bends," which can have serious health repercussions. Therefore, a controlled ascent with safety stops is critical to allow for the gradual release of nitrogen from your body, minimizing the risk of these harmful effects.

In contrast, while hypothermia is a concern during dives due to cold water, it is not directly affected by the rate of ascent. Similarly, the notion that ascending too quickly has no effect on the body is inaccurate because the physiological consequences of rapid ascents are well documented in diving safety protocols. Although oxygen toxicity can be a concern, especially at deeper depths or with increased percentages of oxygen, it is not directly impacted by the rate of ascent. Instead, it is primarily related to depth and the partial pressures experienced while diving. Thus, the focus remains on the importance of controlling ascent speed to prevent nitrogen bubble formation and its associated risks.