What should divers do if they feel lightheaded during a dive?

When divers feel lightheaded during a dive, the appropriate response is to ascend to a shallower depth. This approach is based on the understanding that changes in pressure and the physical environment at deeper levels can exacerbate feelings of lightheadedness, which may be caused by factors such as inefficient gas exchange, low oxygen levels, or nitrogen narcosis.

Ascending to a shallower depth decreases the ambient pressure, which can help alleviate these symptoms and allow for a more favorable gas exchange in the lungs. It is essential for divers to not ignore such feelings, as they can lead to more severe issues if not addressed. This becomes particularly critical because lightheadedness can impede a diver's ability to make sound decisions and manage their diving effectively.

Choosing to descend further in search of more oxygen or to hold one's breath could create dangerous situations, including increased risk of hypoxia or barotrauma. Therefore, ascending to a shallower depth serves as a safe and immediate action for addressing discomfort like lightheadedness while maintaining safety underwater.