Physiology

BY JOHNNY E. BRIAN JR., M.D.

Carbon dioxide (CO2) is the gaseous end product of the aerobic metabolism of oxygen. CO2 is highly soluble in body tissues, and readily diffuses from cells to blood, where circulation transports it to the lungs for elimination. Divers often ignore carbon dioxide, as CO2 is a normal part of life. However, CO2 may have definite and detrimental effects if a diver accumulates an excessive amount of CO2. Understanding how CO2 can become elevated, the symptoms, and the consequences of elevated CO2 can only make us safer divers.

Read more: Carbon Monoxide, Narcosis, and Diving

BY EDDIE BRIAN, JR., M.D.

The oxygen window. Inherent unsaturation. Partial pressure vacancy. Most divers with an interest in decompression diving have likely encountered one of these terms at some time. All three terms are used to describe the same physical phenomenon. For this article, the term oxygen window will be used, as it appears to be the most commonly applied term. However, the terms "inherent unsaturation" and "partial pressure vacancy" more correctly describe the physical phenomenon.

Read more: The Effect of Hyperbaric Oxygen on the Oxygen Window

BY ART RANZ, DDS

Cigarette smoking is one of the largest preventable health and death risks in the United States. It receives enormous amounts of negative media attention and yet millions of people start smoking every year. Unfortunately, it is frequently difficult to have a prudent, scientific discussion about the risks of smoking with someone who is addicted to nicotine. The addiction leads smokers to rationalize or deny the risks of smoking. However, this "head in the sand" response allows them to ignore the obvious impact that smoking has upon their bodies and the more subtle ways it effects many aspects of their lives, such as scuba diving.

Read more: The Impacts of Smoking on Diving