SDI Open Water Scuba Diver Practice Exam 2025 - Free Scuba Diver Practice Questions and Study Guide

During a controlled ascent, making slow, steady vertical movements is essential for safely returning to the surface. This approach helps manage the changes in pressure that occur as a diver rises. Ascending too quickly can lead to serious decompression sickness, also known as "the bends," as nitrogen bubbles can form in the bloodstream due to rapid pressure changes.

By ascending slowly, typically at a rate of no more than 30 feet (about 9 meters) per minute, divers allow their bodies to release excess nitrogen safely. This slow ascent also provides an opportunity to monitor for any signs of discomfort or decompression-related issues, ensuring that divers can respond to any potential problems.

While other actions, such as using a buoy line for stability or signaling with bubbles, may have their place in diving, they do not address the critical aspect of managing ascent speed and pressure changes as directly as ensuring controlled, slow vertical movement does.