Key takeaways:
Decompression sickness, also called “the bends,” is an illness that develops when you rise too quickly from an underwater dive to the surface of the water.
The most common symptoms of decompression sickness are joint pain and rash. But in some cases, symptoms are severe and life-threatening.
You can lower your risk for decompression sickness by following safe ascent protocols after a dive and waiting to fly until it’s safe.
Scuba diving is a way to explore underwater environments, watch animals in their natural habitats, and experience “hidden” underwater worlds. While it can be a very rewarding activity, there are important risks to be aware of. Anyone who scuba dives — from professional divers to weekend adventurers — can develop decompression sickness, or “the bends.”
If scuba diving is in your future, here’s everything you need to know about the bends.
What is the bends, or decompression sickness?
Decompression sickness, also called the bends, is an illness that can happen if you move too quickly from a high-pressure environment to a low-pressure one. The bends can cause a range of symptoms, from muscle and joint aches to difficulty breathing.
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What causes decompression sickness?
Decompression sickness can happen when you move from an area of high pressure (underwater) to an area of lower pressure (the surface of the water). At high pressures, gas dissolved in the body can move freely and enter the bloodstream. As you move back into a lower pressure, the gas moves out of your bloodstream and back into body tissues.
But this process needs to happen slowly. If you go to the surface (ascend) too fast, the gas doesn’t have enough time to settle back into place. Instead, it can get trapped in spots it doesn’t belong — like your bloodstream, joints, and the tissue around your bones. When gas gets trapped like this, it can cause damage to your body.
What are the symptoms of decompression sickness?
Decompression sickness can affect many parts of your body. Symptoms of the bends include:
Joint pain: Gas bubbles can get stuck in joints and stretch ligaments and tendons in ways they shouldn’t. The result is a deep and throbbing pain that you feel inside your joint. Your elbows and shoulders are the most common spots, but you can also get the bends in your knees and hips.
Numbness and weakness: If gas bubbles get trapped around your spinal cord, you can develop numbness, tingling, and weakness in your arms or legs. Some people also experience back pain, trouble with bladder control, or even paralysis.
Trouble talking and walking: Gas bubbles in your bloodstream can interrupt blood flow to your brain. This may cause memory loss and trouble speaking or walking (called “the staggers”).
Skin changes: Gas bubbles can get trapped in smaller blood vessels and in the lymphatic system. This can cause unusual rashes, localized swelling, and other skin changes.
Vertigo: When gas bubbles get trapped in your inner ear, you can develop vertigo. This can cause dizziness, nausea, headaches, and ear ringing.
Trouble breathing: Some people develop coughing, trouble breathing, and chest pain (called “the chokes”). These symptoms aren’t common, unless you’ve gone on a long or very deep dive.
Chest pain: Very rarely, gas bubbles enter your arteries and cause an arterial gas embolism. Arterial gas embolisms are life-threatening, and symptoms often look like a heart attack, including chest pain.
Almost everyone who develops decompression sickness shows symptoms within 3 hours of reaching the surface. It’s very rare to develop symptoms more than 24 hours after a dive.
Who is at risk of getting decompression sickness?
Anyone who experiences pressure changes can develop decompression sickness. Professional divers and people who work in underwater or tunnel construction are frequently exposed to pressure changes. So, they’re most likely to develop the bends.
Even casual scuba divers can develop symptoms if they ascend to the surface too fast.
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Things that can increase your risk of developing decompression sickness include:
Long dives
Deep dives
Many dives over a few days
Quicker ascents
If you have a patent foramen ovale (a type of congenital heart problem), you shouldn’t dive without talking to your healthcare team first. People with patent foramen ovale are at a much higher risk for developing severe decompression sickness.
Can you get the bends without scuba diving?
Yes. It’s rare, but there are cases of people developing the bends after freediving. It’s also possible to get decompression illness from flying in a nonpressurized aircraft. Keep in mind that commercial aircrafts all have pressurized cabins. So, you’re unlikely to develop decompression sickness from a commercial flight — unless you’ve recently been scuba diving. High-altitude aviators and astronauts are the groups most at risk for developing decompression sickness from flying.
How do you treat decompression sickness?
The treatment for decompression sickness is hyperbaric oxygen therapy. During hyperbaric oxygen therapy, you lie inside a hyperbaric chamber, which is a tube-like structure. The tube is filled with 100% oxygen, and a specialist increases the pressure inside the tube. This treatment helps to dissolve gas bubbles inside your body.
Studies show that 80% of people with decompression sickness recover completely. People with gas bubbles around their spinal cords or inner ear are more likely to have ongoing symptoms even after treatment.
How can you avoid getting decompression sickness?
Whether it’s your first dive or your hundredth, always follow the proper ascent protocol. Doing so will help keep you from rising to the surface too fast and developing decompression sickness. If you’re just learning to scuba dive, always work with certified trainers to learn proper ascent techniques.
The data is clear: It’s dangerous to fly too soon after your last dive. Aircrafts have lower pressures, which will cause more gas bubbles to form in your body.
Experts recommend waiting:
12 hours before flying if you’ve done 2 hours or less of diving in the previous 48 hours
24 hours before flying if you’ve done multiple dives or deeper dives during the previous 48 hours
48 hours (or longer) before flying if your dives included decompression stops
Frequently asked questions
The bends gets its name from the stooped, or “bent,” posture of men who suffered from decompression sickness while working on the Brooklyn Bridge. More than a hundred cases of decompression sickness were diagnosed among workers building the bridge in underwater caissons.
Yes, the bends can be life-threatening. Severe cases can also lead to permanent nerve damage and even paralysis.
The bends gets its name from the stooped, or “bent,” posture of men who suffered from decompression sickness while working on the Brooklyn Bridge. More than a hundred cases of decompression sickness were diagnosed among workers building the bridge in underwater caissons.
Yes, the bends can be life-threatening. Severe cases can also lead to permanent nerve damage and even paralysis.
The bottom line
Decompression sickness (the bends) can happen after scuba diving. The symptoms include joint pain, vertigo, and numbness. If you dive, you can lower your risk of getting decompression sickness by slowly rising to the surface after a dive. You should also wait between 12 to 48 hours to fly after diving.
For more information on how to dive safely, visit Divers Alert Network, a nonprofit organization that provides expert medical information about diving.
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References
Carturan, D., et al. (2002). Ascent rate, age, maximal oxygen uptake, adiposity, and circulating venous bubbles after diving. Journal of Applied Physiology.
Cooper, J. S., et al. (2023). Decompression sickness. StatPearls.
de la Cruz, R. A., et al. (2024). Aerospace decompression illness. StatPearls.
Divers Alert Network. (n.d.). Chapter 3: Diagnosing decompression sickness.
Divers Alert Network. (n.d.). DAN.
Divers Alert Network. (2020). Treating decompression sickness.
Divers Alert Network. (2021). Freediving not a free pass out of DCS.
Freiberger, J. J., et al. (2002). The relative risk of decompression sickness during and after air travel following diving. Aviation, Space, and Environmental Medicine.
Go Flight Med. (2013). Decompression illness in aviation.
Hexdall, E. J., et al. (2024). Patent foramen ovale in diving. StatPearls.
Kas, S. (2019). Caisson and the Brooklyn Bridge. InDepth.
Moon, R. E. (2025). Decompression sickness. Merck Manual.
Pollock, N. W., et al. (2017). Updates in decompression illness. Emergency Medicine Clinics of North America.
Sheffield, P. J. (1990). Flying after diving guidelines: A review. Aviation, Space, and Environmental Medicine.
U.S. Food and Drug Administration. (2021). Hyperbaric oxygen therapy: Get the facts.
Vann, R. D., et al. (2011). Decompression illness. Lancet.
Walker, J. R., III., et al. (2023). Diving gas embolism. StatPearls.
