SDI Open Water Scuba Diver Practice Exam 2026 - Free Scuba Diver Practice Questions and Study Guide

When a diver begins to feel cold underwater, ascending to a shallower depth or ending the dive becomes the most prudent action. Cold sensations underwater can indicate that the diver is experiencing a drop in body temperature, which increases the risk of hypothermia. Ascending to a shallower depth can lead to warmer water, as temperatures generally increase as divers rise towards the surface. Ending the dive is also a critical option if discomfort persists, as it ensures the diver's safety and well-being.

Continuing the dive until the planned time can exacerbate the situation if the diver is experiencing cold, leading to more significant risks to health and safety. Swimming faster to warm up might initially seem like a solution, but it can actually increase heat loss due to increased blood flow to the skin's surface while also causing fatigue. Taking a break underwater without movement can allow the body to cool further, which is not advisable when already feeling cold. Thus, the best approach is to respond proactively by ascending or terminating the dive to maintain comfort and safety.