Understanding Decompression Sickness: What Every Diver Should Know

By Craig Clark

Throughout my years as the owner and senior scuba instructor at the Aquatic Center of Ocala, I have witnessed significant changes in the scuba diving industry, particularly in how basic Open Water certification courses are taught.

While advancements in equipment, training techniques, and safety procedures have greatly improved our sport, I believe one area deserves greater attention: the medical science behind diving and the prevention of decompression sickness (DCS).

One organization that has made tremendous contributions to diver safety is the Divers Alert Network (DAN). Through decades of research, medical studies, and accident investigations, DAN has helped the diving community better understand the physiological effects of diving and identify factors that may contribute to diving-related injuries.

Understanding Decompression Sickness

Decompression sickness, commonly referred to as "the bends," is introduced during basic Open Water training. However, I believe many divers leave their initial certification courses without a complete understanding of the factors that can increase their risk.

Traditionally, divers have been taught the importance of ascending slowly, making appropriate safety stops, remaining within established dive limits, and allowing sufficient time before flying.

While these precautions are essential, they do not eliminate every risk associated with decompression sickness.

When we breathe compressed gas underwater, the increased surrounding pressure causes additional nitrogen to dissolve into our body's tissues. As we ascend and the surrounding pressure decreases, that nitrogen gradually moves out of our tissues and is eliminated through normal respiration.

Even after reaching the surface, residual nitrogen remains in the body and requires additional time to be eliminated.

If nitrogen forms problematic bubbles in the body's tissues or bloodstream, decompression sickness can occur.

One important lesson I have learned throughout my diving career is that a diver can follow established dive procedures and still experience decompression sickness.

Early in my career as an instructor, I witnessed situations that caused me to question why this happens. Those experiences encouraged me to study the research and medical information published by DAN.

What I discovered reinforced the importance of understanding what we do not only during a dive, but also after we return to the surface.

The Risks Don't Necessarily End When the Dive Is Over

Consider a situation I observed during a diving trip.

After completing the day's dives, one individual returned to the hotel, took a hot shower, and then spent approximately two hours relaxing on the beach in the intense sun. That diver subsequently developed symptoms of decompression sickness.

Although it is not possible to establish the exact cause of an individual DCS incident without a medical evaluation, research suggests that significant heat exposure soon after diving may influence decompression stress by affecting circulation and the behavior of dissolved gases.

This is one reason divers should exercise caution with very hot showers, hot tubs, saunas, and prolonged exposure to excessive heat immediately following a dive.

Strenuous Exercise After Diving

Another concern is strenuous physical activity shortly after diving.

Over the years, I have encountered divers who believe that once their equipment is put away, they can immediately return to demanding activities such as weightlifting, jogging, or intense exercise.

However, vigorous physical exertion soon after diving may increase decompression stress and potentially contribute to the development of DCS.

Heavy exercise can affect blood circulation and the movement of dissolved gases throughout the body. For this reason, divers should allow appropriate recovery time before participating in strenuous physical activities.

Every diver's physiology is different. Factors such as age, fitness level, hydration, dive depth, bottom time, repetitive diving, and individual susceptibility can influence decompression risk.

There is no single recovery period that guarantees every diver will be completely free of risk.

The important lesson is simple: Your responsibility for dive safety does not end when you surface.

Education Is One of Our Greatest Safety Tools

As instructors, we have a responsibility to prepare divers not only to operate their equipment and perform underwater skills, but also to understand the physiological demands that diving places on the human body.

I believe greater emphasis should be placed on post-dive activities, decompression stress, and recognizing the signs and symptoms of DCS during entry-level training.

The more informed our divers become, the better equipped they are to make responsible decisions before, during, and after every dive.

Thanks to organizations such as DAN, we have access to valuable medical research and educational resources that continue to improve our understanding of diving safety.

Why I Recommend Divers Alert Network

If you are an active scuba diver and are not currently a member of Divers Alert Network, I strongly encourage you to consider joining.

DAN provides access to diving medical information, educational resources, safety research, and emergency assistance services.

DAN also offers specialized dive accident insurance plans that may help cover eligible expenses associated with diving injuries, including hyperbaric oxygen treatment, emergency medical transportation, and other covered services, depending on the policy selected.

Many traditional health insurance policies have limitations or exclusions related to certain diving injuries, emergency evacuations, or specialized treatments. Divers should review their individual policies carefully rather than assume they are fully covered.

Treatment for serious decompression sickness can be extremely expensive. Recompression therapy using hyperbaric oxygen is a principal treatment for DCS, and prompt medical evaluation is critical whenever symptoms are suspected.

Having appropriate dive accident coverage can provide valuable financial protection and peace of mind.

Final Thoughts

Scuba diving is an extraordinary activity that allows us to explore a world few people ever experience. With proper training, sound judgment, and an understanding of the physiological effects of diving, we can significantly reduce many of the risks associated with our sport.

My goal in sharing these experiences is not to discourage anyone from diving, but rather to encourage every diver to become more knowledgeable about their personal safety.

Dive conservatively. Continue learning. Respect your body's limitations. And remember that safe diving practices extend well beyond your time underwater.

I encourage every diver to learn more about the research, educational programs, and insurance options available through Divers Alert Network.

Visit www.dan.org for additional information.

Craig Clark

Owner & Senior Scuba Instructor

Aquatic Center of Ocala

Ocala, Florida