What is the Bend: A Diver Guide to Decompression Sickness & Prevention

One of the most critical risks every diver must be aware of is decompression sickness (DCS), commonly known as “the bends.”

Decompression sickness occurs when nitrogen bubbles form in the body due to rapid pressure changes, potentially causing serious health issues if left untreated. Whether you’re a seasoned diver or just starting, understanding DCS is essential for your safety and the safety of those you dive with.

In this article, we’ll explore what DCS is, its causes, symptoms, prevention strategies, and treatment options, empowering you with the knowledge to dive confidently and responsibly.

What is Decompression Sickness?

Decompression sickness (DCS), often called “the bends,” occurs when dissolved nitrogen in your body forms bubbles due to rapid pressure changes.

While diving, your body absorbs N₂ from the compressed air you breathe. At higher pressures underwater, more N₂ dissolves into your tissues and bloodstream.

When you ascend too quickly, the pressure around you decreases faster than your body can safely release the N₂. This causes the N₂ to come out of the solution and form gas bubbles which can block blood vessels, irritate tissues, and cause symptoms like joint pain, numbness, fatigue, dizziness, or even serious neurological or cardiovascular issues.

The risk increases with deeper dives, longer time spent underwater, or repeated dives with short surface intervals. Factors like dehydration, age, and body composition can also make you more susceptible. To prevent DCS, you must ascend slowly, follow dive tables or use dive computers, and allow enough time for N₂ to safely leave your body before surfacing.

Signs and Symptoms of DCS

The signs and symptoms of DCS often depend on how much nitrogen has built up in your body and how quickly it make packets. Recreational divers are at particular risk if they fail to follow proper ascent protocols.

Symptoms can range from joint pain and fatigue to more serious effects like neurological problems, including numbness, confusion, or even temporary loss of muscle control. In some cases of decompression sickness, symptoms may appear within minutes, but they can also develop hours after diving — sometimes as late as 12 hours or more.

To reduce the risk of sickness, it’s essential to ascend slowly and allow your body to safely pressurize during decompression stops. The Divers Alert Network (DAN) emphasizes the importance of monitoring for signs of DCS and seeking prompt treatment if you suspect a problem. Oxygen therapy, which involves breathing pure oxygen in a pressurized chamber, is the primary treatment for DCS. This recompression therapy helps reduce the size of N₂ bubbles and restore proper blood flow, significantly improving recovery.

Recognizing the symptoms early is crucial, as ignoring them can lead to more severe complications. If you notice unusual sensations or discomfort within hours after diving, seek medical help immediately to avoid long-term damage. Whether you’re an experienced diver or just starting, understanding DCS and how to prevent it can make your underwater adventures much safer.

Causes of Decompression Sickness

1. Rapid Ascent

When you ascend too quickly after a scuba dive, the pressure around you decreases faster than your body can handle. This causes N₂ to leave your tissues too quickly and form bubbles, which  can lead to decompression illness. Divers who go without controlling their ascent risk experiencing joint pain, dizziness, or neurological symptoms. If you suspect decompression illness after a rapid ascent, seek medical help immediately.

2. Deep or Prolonged Dives

The longer you stay underwater or the deeper you go, the more N₂ your body absorbs. When you return to diving after such dives, you might already have residual N₂ in your tissues. This increases the chance of getting the bends if you don’t follow safe diving practices. Planning your dive carefully helps you avoid the bends after deep or extended dives.

3. Repetitive Dives

If you do multiple dives in a short period, the N₂ from earlier dives may not fully leave your body. Recent diving experience like this increases your chances of decompression illness. Proper surface intervals are necessary to prevent the bends. Always monitor your diving history and N₂ levels before your next dive.

4. Improper Dive Planning

Failing to plan your dives properly can lead to unsafe conditions. If you don’t use a dive computer or follow dive tables, you might ascend too quickly or stay underwater too long. These mistakes increase the chances of generating packs in your tissues. Proper planning helps you avoid the bends and ensures safety. 

5. Flying After Diving

Flying soon after a dive exposes you to lower air pressure, which can worsen N levels in your body. This situation is dangerous because it forces N₂ packs to expand. If you’ve had a recent diving experience, wait at least 18-24 hours before flying to prevent decompression illness.

6. Dehydration

Dehydration thickens your blood, making it harder for your body to eliminate N₂. This can increase your risk of generating bubbles during or after a dive. Drinking water before and after diving helps reduce this risk of the bends. Dehydration can also affect the signs or symptoms of decompression, making them worse.

7. Age and Physical Fitness

Your age and physical condition play a big role in how your body handles pressure changes. Older divers or those who are unfit are at higher risk of getting the bends. Lung disease may also increase your susceptibility to decompression illness. Stay active and maintain good health to reduce your risks while diving.

8. Body Composition

If you have a higher body fat percentage, your tissues absorb more N₂. This increases your risk of bubbles forming in your body during a dive. Divers with higher fat levels may experience stronger signs and symptoms, which usually appear after they surface.

9. Cold Water Diving

Cold water can slow down your circulation, making it harder for your body to eliminate nitrogen efficiently. This delay can have a direct effect on symptoms of decompression illness. When diving in cold conditions, ensure proper gear and follow safety protocols to prevent the bends.

10. Underlying Health Conditions

Certain health issues, like lung disease, may increase your risk of decompression illness. These conditions make it harder for your body to manage nitrogen during and after a dive. If you have health concerns, consult a doctor first.

11. Equipment Malfunctions

If your equipment fails during a dive, you may be forced to ascend rapidly. This position is dangerous because it doesn’t allow your body enough time to adjust. Regular equipment checks are essential to prevent decompression illness.

Treatments for the Bends (Decompression Sickness)

1. Immediate First Aid

When you suspect the bends, your first response is crucial. Stop all activities immediately to prevent further nitrogen absorption. Position yourself lying flat, as this promotes even blood flow and reduces the risk of N2 pockets traveling to critical areas like the brain or spinal cord. Administer 100% oxygen through a mask or tank if available. Oxygen helps eliminate nitrogen from your bloodstream more efficiently, minimizing the risk of worsening symptoms.

Hydration plays an essential role in recovery. Drink water or an electrolyte solution to combat dehydration, which can slow nitrogen elimination and worsen symptoms. Avoid alcohol or caffeine as they can dehydrate you further. Refrain from any physical activity because it increases your metabolic rate, potentially worsening N2 packet formation and spreading them further into your tissues. These steps provide a critical buffer while awaiting professional medical help.

2. Seek Medical Assistance

Once immediate first aid has been provided, get medical assistance as quickly as possible. Call emergency services or head to the nearest hospital. Provide medical personnel with detailed information about your recent underwater activity, including the depth, duration, ascent speed, and any issues experienced before or after surfacing. Sharing this history helps professionals quickly assess your condition and decide the best course of action.

If you are in a remote area or a popular location for underwater exploration, contact the Divers Alert Network (DAN). They specialize in emergencies related to these activities and can guide you to the nearest treatment facilities and the best transport options. The quicker you receive professional treatment, the higher the chances of full recovery without long-term complications.

3. Hyperbaric Oxygen Therapy (Recompression Therapy)

Hyperbaric oxygen therapy is the gold standard for treating decompression sickness. In a chamber, the pressure increases to simulate conditions at depth. This pressure helps reduce the size of nitrogen bubbles in your body, allowing them to dissolve back into your bloodstream and be safely exhaled.

You will breathe 100% oxygen in the chamber, which speeds up nitrogen elimination and restores oxygen levels in tissues that were deprived. This treatment reduces swelling and inflammation caused by bubbles and restores blood flow to affected areas. In severe cases involving symptoms or paralysis, recompression therapy can significantly improve outcomes, although it may require multiple sessions.

The duration of a session in the chamber depends on the severity of your symptoms. A typical session lasts 4-5 hours, but follow-up treatments may be necessary.

4. Monitoring and Follow-Up

Recovery doesn’t end after hyperbaric treatment. Medical professionals will closely monitor you for any lingering symptoms, such as fatigue, weakness, or difficulty concentrating. These symptoms may indicate incomplete resolution of nitrogen bubbles or minor tissue damage. You may need additional hyperbaric sessions if symptoms persist.

During this period, avoid any activities that expose you to pressure changes until cleared by a medicine specialist. These activities can reintroduce nitrogen into your system, worsening your condition. It’s essential to follow your doctor’s advice and attend all scheduled follow-up appointments to ensure a full recovery.

5. Prevention of Future Episodes

Treating the bends is only half the battle; preventing it from happening again is equally important. Learn to plan your underwater activities meticulously. Use a computer to monitor your depth, time, and ascent rate in real time. Follow safety tables to ensure you stay within safe limits and take proper surface intervals between sessions.

Hydration is another key factor. Always drink plenty of water before and after being in the water to keep your body functioning optimally. Avoid going underwater when you’re feeling unwell, tired, or under the influence of alcohol, as these factors can increase your risk of decompression sickness. Maintaining good physical fitness and health also plays a significant role in your body’s ability to manage nitrogen.

Lastly, take refresher courses or advanced training to reinforce your knowledge about safe practices. Being informed, prepared, and cautious is the best way to minimize your risk of encountering decompression sickness again.

Conclusion

Decompression sickness is a serious risk that every diver must understand and take precautions against. By knowing the causes, recognizing the signs and symptoms, and following prevention strategies, you can enjoy safer and more fulfilling underwater experiences.

At Spirit Liveaboards, we go beyond providing luxurious amenities. Our expert team ensures you have access to world-class knowledge and safe practices. Whether you’re exploring the pristine waters of the Maldives or the vibrant reefs of Fiji, we are committed to offering unparalleled adventures with safety at the forefront.

Dive with confidence and let us take care of the rest!