What are the signs of an inadequate air supply during a dive?

The signs of an inadequate air supply during a dive include rapid breathing, heavy exertion, and increasing anxiety. When a diver is low on air, their body instinctively reacts by increasing respiration rates as a physiological response to the lack of oxygen. This can lead to feelings of anxiety or panic, as the diver realizes they may not have enough air to safely complete their dive. Heavy exertion may also occur if the diver is struggling against their environment or working harder to maintain buoyancy or stability, which further exacerbates the situation by using up air more quickly.

In contrast, a stable heart rate and calm demeanor typically indicate that a diver is within their comfort zone and has an adequate air supply, making the second choice incorrect. An unexpected decrease in overall body temperature does not directly indicate air supply issues; rather, it can be influenced by water conditions, exposure time, or inadequate thermal protection, ruling out the third option. Lastly, increased flexibility and buoyancy are not related to air supply; they pertain more to a diver's skills and equipment adjustments, making the fourth choice an inappropriate response to inadequate air supply.