What is a common symptom of carbon dioxide retention while diving?

A common symptom of carbon dioxide retention while diving includes a variety of physiological responses, which is why the answer encompasses all listed options. When carbon dioxide accumulates in the bloodstream, the body works to compensate for this buildup, leading to several symptoms.

Increased heart rate occurs as the body tries to deliver more oxygen to tissues while simultaneously attempting to remove excess carbon dioxide. This is a natural response of the cardiovascular system to maintain oxygen delivery despite the elevated levels of CO2.

Dizziness is another symptom that can arise due to the alteration in blood chemistry. As carbon dioxide levels rise, it can affect the body's pH balance and, subsequently, lead to feelings of lightheadedness or dizziness, as the brain may not be receiving the oxygen it needs effectively.

Shallow breathing is a compensatory mechanism that may occur as the body senses high levels of carbon dioxide. The respiratory rate may adjust to shallow and rapid breath patterns in an attempt to reduce CO2 retention, although deeper breaths are usually more effective in expelling carbon dioxide.

Since all these symptoms can manifest from carbon dioxide retention, they collectively illustrate the body's response to this condition, making the option of "All of the above" the most comprehensive and accurate choice.