Scuba Diving And Health: Decompression Sickness

Scuba Diving And Health: Decompression Sickness
Anna Segeren

What is Decompression Sickness and What Causes It?

Decompression Sickness (DCS) is a condition in which rapid changes of pressure in an environment causes gases to form bubbles of gas, mainly nitrogen.

In diving, when the diver descends, nitrogen is breathed in and is dissolved in the blood and tissues. Subsequently, nitrogen leaves the blood and tissues and forms into tiny bubbles when the diver ascends due to the drop in the surrounding pressure.

If the nitrogen is not re-absorbed into the blood and exhaled through the lungs, these tiny bubbles can form into larger bubbles and cause serious damage to your body.

Read more about the effects of nitrogen here.

A variety of DCS symptoms may then arise when these bubbles become large in number and block the flow of blood.

Things such as diver-related errors, misuse of dive tables, malfunctioning dive computers or inaccurate depth gauges, are also contributory factors leading to DCS.

What Are The Instances In Which DCS Might Commonly Occur?

There are three instances in which decompression sickness may occur:

Diver’s crossing their allowable depth are at risk of decompression sickness – Credit: Jon Milnes

When Might a Diver Be At Risk For Decompression Sickness?

Scuba divers are at risk for decompression sickness under the following conditions:


What Are the Signs and Symptoms of DCS?

The most common symptom of decompression sickness is pain in the arms or leg joints.

The other symptoms and signs that can be observed are:

  • Blotchy skin rash
  • Fatigue or weakness
  • Skin itchiness
  • Dizziness
  • Shortness of breath
  • Abdominal distress
  • Chest pain
  • Skin swelling


The above signs and symptoms may occur when the diver is still underwater, or they may come about as late as 36-48 hours after a dive.

How Can It Be Prevented?

The best way to prevent decompression sickness is to avoid the conditions that put a diver at risk of DCS, even if you are highly trained. Remember not to go beyond the limits of your training at any time.

With dives that require decompression stops, be observant to your dive computer or strictly follow your dive table, as it determines the decompression stops required for a particular dive profile.

Here’s more about Safety Stops.

Do not fly shortly after diving. You need to have at least 12 hours of surface interval after one dive and 18-24 hours after multiple dives.

A dive group on a decompression safety stop – Credit: Bartlomiej K. Kwieciszewski

How is DCS Treated?

Decompression sickness can only be treated through recompression in a high-pressure chamber. This apparatus slowly increases pressure on the person, forcing the bubbles to dissipate.

The pressure is then gradually reduced to enable the person to breathe out the extra gases. Operation of the high-pressure chamber shall only be done by qualified medical personnel.

As soon as you suspect DCS, administer 100% oxygen through a tight-fitting mask. As soon as possible, seek for Emergency Medical Service (EMS) or the nearest medical assistance available.

To learn more about administering emergency medical assistance, an Emergency First Response (EFR) Course is being offered by PADI which includes CPR, Automatic External Defibrillator (AED) and First Aid training to divers.

The control board of a high pressure chamber – Credit: Gordon Milligan

What Are Its Ill-Effects?

DCS has no long-term effects if treated immediately. However, delayed or no treatment, or repetitive DCS, may cause permanent damage such as paralysis, bone and brain damage, and in severe cases, death.

It is not exceedingly difficult to avoid DCS. Even if one engages in deep water diving, the proper use of diving gadgets like a dive computer, dive tables or a dive watch would go far in keeping the diver safe, when the rules and recommendations are followed properly.

With keen knowledge, proper equipment and the best training available from a certified instructor, decompression sickness will be less likely to happen to a diver.


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