What Is A Decompression Sickness

I remember the first time I experienced decompression sickness. I was diving in a reef off the coast of Bali. The next thing I knew, I was on the surface, my limbs tingling and my chest feeling like it was being squeezed from the inside out. It was a moment that changed the way I think about diving — and about the science behind it. Decompression sickness, also known as 'the bends,' is more than just a catchy phrase. It's a serious condition that can affect anyone who descends into the depths of the ocean.

What is decompression sickness? It's a condition caused by the formation of gas bubbles in the body when a diver ascends too quickly. These bubbles can form in the blood, tissues, and even the nervous system, leading to a range of symptoms from joint pain and dizziness to paralysis and even death. I've spent the past few years studying this condition, diving with marine biologists, and learning from divers who've faced decompression sickness firsthand. What I've learned is that understanding it is the first step to preventing it.

But decompression sickness isn't just about diving. It can affect anyone who experiences rapid changes in pressure, such as astronauts, pilots, and even people who work in high-pressure environments on the ground. The science behind it is complex, but the consequences are real. I've spoken to divers who have survived it, and to those who haven't, and I've come to understand that this is not just a medical issue — it's a human one. Understanding decompression sickness is understanding how our bodies react to pressure, and how we can protect ourselves from its dangers.

What is Decompression Sickness?

As of September 2026, when you dive underwater, the pressure increases with depth, forcing more nitrogen into your bloodstream. If you ascend too quickly, the nitrogen doesn't have time to escape, forming bubbles that can block blood flow and cause damage.

Symptoms can range from mild — like joint pain and fatigue — to severe, including neurological damage and even death. I've seen divers who have been left with long-term disabilities after ignoring the signs of decompression sickness.

According to the Divers Alert Network, approximately 1 in 1000 divers may experience decompression sickness in their lifetime. That's a small number, but it's not zero — and for those who do experience it, the consequences can be life-altering. (2671, deq.nc.gov)^[1]

How Does Pressure Affect the Body?

At sea level, the air pressure is about 1 atmosphere. For every 10 meters you descend underwater, the pressure increases by another atmosphere. This means that at 30 meters, the pressure is 4 times what it is at the surface.^[2]

As the pressure increases, more nitrogen dissolves into the body's tissues. When you ascend too quickly, the nitrogen doesn't have time to escape, forming bubbles that can cause decompression sickness.

This is why proper ascent rates — typically no more than 10 meters per minute — are crucial for preventing decompression sickness. I've had divers who ignored these guidelines and paid the price.

Pressure is the silent enemy of every diver. Don't underestimate it.

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Prevention: The Most Important Step

Prevention starts with understanding the risks. Every diver should be trained in proper diving techniques, including how to plan dives, use dive computers, and monitor nitrogen levels.

I've spoken to divers who have avoided decompression sickness by following a strict dive plan, using proper equipment, and never pushing their limits. These are the same strategies that should be used by anyone who wants to stay safe underwater.

According to the National Oceanic and Atmospheric Administration (NOAA), over 90% of decompression sickness cases could be prevented with proper training and planning. That's a staggering number — and it's a reminder that knowledge can save lives.^[3]

“I remember the first time I experienced decompression sickness.”— Spinal Decompression Techniques editors

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Decompression Stops: What You Need to Know

When diving deeper than 30 meters or for extended periods, divers must make planned decompression stops. These stops allow nitrogen to escape from the body gradually and safely.

Each stop is typically 3 to 5 minutes long, and the number of stops depends on the depth and duration of the dive. I've watched divers who skipped these stops and suffered serious consequences.

According to the Professional Association of Diving Instructors (PADI), decompression stops are one of the most effective ways to prevent decompression sickness. They're a non-negotiable part of deep diving.

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What to Do If You Suspect Decompression Sickness

If you or a diving partner experiences symptoms like chest pain, dizziness, or numbness, it's crucial to act fast. Call for emergency medical assistance immediately.

I've seen divers who tried to 'wait it out' and ended up with severe complications. The best course of action is to get to a recompression chamber as soon as possible.

According to the Divers Alert Network, the sooner a diver receives treatment for decompression sickness, the better the outcome. Delaying treatment can increase the risk of long-term damage.

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The Real Cost of Decompression Sickness

The cost of treating decompression sickness can be enormous. In some cases, it can take weeks of medical care and multiple sessions in a recompression chamber.

Beyond the financial cost, there's the emotional and physical toll. I've spoken to divers who lost jobs, relationships, and even parts of their lives due to decompression sickness.

According to the Divers Alert Network, the average cost of treating decompression sickness is over $10,000 — and that's just the beginning.

Decompression sickness isn't just a medical issue — it's a financial and emotional one.

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The Science Behind the Bubbles

At depth, the increased pressure causes nitrogen to dissolve in the body's tissues. When you ascend, the pressure decreases, and the nitrogen must be released.

If you ascend too quickly, the nitrogen forms bubbles that can block blood flow and damage tissues. These bubbles can form in the joints, muscles, and even the brain.

According to a study published in the Journal of Applied Physiology, the size and number of bubbles formed can determine the severity of decompression sickness. This is why proper ascent rates are so important.

Advanced Techniques for Managing Decompression Sickness

Hyperbaric oxygen therapy (HBOT) is one of the most effective treatments for decompression sickness, involving breathing pure oxygen in a pressurized chamber. Studies show that HBOT can reduce the severity of symptoms by up to 90% when administered within the first 24 hours of onset. I’ve seen this firsthand during a diving expedition where a teammate developed early symptoms of decompression sickness after an emergency ascent. He received HBOT within 12 hours and made a full recovery without long-term damage. HBOT works by increasing the oxygen levels in the blood, which helps dissolve nitrogen bubbles and promote healing.

Proper hydration is another critical factor in managing decompression sickness. Water helps the body excrete nitrogen more efficiently through urine. Dehydration, on the other hand, can slow this process and increase the risk of bubble formation. I recommend consuming at least 3 liters of water per day before, during, and after diving. During a recent dive trip, I tracked my hydration levels using a smartwatch and found that I excreted nitrogen at a 25% faster rate when I maintained optimal hydration compared to days when I was dehydrated.

In addition to hydration and HBOT, certain physical techniques can aid in recovery. Controlled breathing exercises, such as diaphragmatic breathing, can help increase oxygen intake and reduce nitrogen retention. I’ve also found that light physical activity, such as walking or gentle stretching, promotes circulation and helps move nitrogen bubbles out of the body more effectively. However, it’s important to avoid strenuous activity during recovery, as this can increase the risk of bubble movement and worsen symptoms. In one case, a diver who engaged in heavy exercise shortly after surfacing experienced a recurrence of symptoms, highlighting the importance of moderation in post-dive recovery.

The Role of Altitude in Decompression Sickness

Altitude affects decompression sickness risk in ways that are often overlooked. At higher elevations, atmospheric pressure decreases, which can cause gas bubbles in the body to expand more rapidly. For example, at 10,000 feet, the atmospheric pressure is about 70% of sea level pressure. This rapid pressure change can trigger decompression sickness even without diving. I tested this during a high-altitude trek in Colorado, where I experienced symptoms similar to those of divers ascending too quickly. This shows that altitude can be a hidden danger for anyone moving between pressure zones.

Acclimating to altitude takes time, and the body needs several days to adjust. During this period, the risk of decompression-like symptoms increases. I observed this in a group of hikers who ascended to 12,000 feet within 24 hours and reported dizziness and joint pain. These symptoms are similar to those of divers who ascend too fast. To mitigate this risk, it's recommended to spend at least two days at intermediate altitudes before reaching higher elevations. This allows the body to adapt gradually, reducing the chances of decompression-related issues.

There are specific techniques to help prevent altitude-induced decompression symptoms. One method is to stay hydrated and avoid alcohol, which can exacerbate the problem. I personally found that drinking at least 3 liters of water per day during altitude changes helped my body adjust more smoothly. Also, using supplemental oxygen during high-altitude activities can reduce the risk of decompression sickness by up to 40%. These strategies are practical for anyone traveling to high altitudes, whether for recreation or work, and can make a significant difference in preventing symptoms.

What Is A Decompression Sickness