Diving Illnesses: Symptoms, Prevention, and Liveaboard Safety

Exploring the underwater world offers an incredible opportunity for adventure, but it also comes with risks. Understanding common illnesses, their symptoms, and how to prevent them is essential for every enthusiast’s safety and enjoyment.

In this article, we’ll explore the most common conditions, how to recognize them, and the steps you can take to ensure a safe and worry-free experience—especially when booking professional liveaboard trips with expert support and medical care.

What Are Diving Illnesses?

These illnesses are medical conditions caused by the effects of pressure changes, gas absorption, and environmental factors experienced during underwater activities. These conditions arise when gases like nitrogen or oxygen behave differently in the body under varying pressures, leading to issues such as decompression sickness, nitrogen narcosis, or barotrauma.

Proper training, careful planning, and professional guidance, such as on liveaboard trips, are essential to prevent these illnesses and ensure a safe experience.

1. Decompression Sickness (DCS) – “The Bends”

Decompression sickness, also called the bends, occurs when nitrogen gas forms bubbles in the bloodstream and tissues during or after a rapid ascent. This happens because the pressure decreases too quickly, causing dissolved nitrogen to come out of solution. These bubbles can block blood vessels, damage tissues, and lead to a range of symptoms, from mild discomfort to life-threatening conditions.

Symptoms of Decompression Sickness (DCS)

• Joint or muscle pain: Often felt in the shoulders, elbows, or knees, this is the most common symptom of DCS.
• Fatigue: Divers may feel unusually tired or weak.
• Dizziness or confusion: Nitrogen bubbles affecting the brain can cause disorientation or difficulty thinking clearly.
• Skin rashes or itching: Sometimes called “skin bends,” this occurs when bubbles form under the skin.
• Numbness or tingling: Bubbles in the nervous system can cause unusual sensations or loss of feeling.
• Paralysis or difficulty breathing: In severe cases, bubbles in the spinal cord or lungs can lead to paralysis or respiratory distress.

Prevention of Decompression Sickness (DCS)

To avoid decompression sickness, divers should ascend slowly, ideally at a rate of 9 meters (30 feet) per minute or slower.

Always follow tables or computers to stay within no-decompression limits, and perform safety stops at 5 meters (15 feet) for 3-5 minutes.

Additionally, avoid flying or traveling to high altitudes for at least 12-24 hours to allow excess nitrogen to safely leave the body.

Proper hydration and fitness within your training limits also reduce the risk of DCS.

2. Nitrogen Narcosis – “Rapture of the Deep”

Nitrogen narcosis is a condition that affects divers at deep depths, typically beyond 30 meters (100 feet).

It occurs when excess nitrogen remains dissolved in the body tissue and begins to act like an anesthetic, impairing cognitive and motor functions.

This illness is sometimes referred to as the “rapture of the deep” because it can cause a sense of euphoria or overconfidence, similar to being intoxicated.

While the effects are temporary and reverse upon ascending to shallower depths, nitrogen narcosis can be dangerous if it leads to poor decision-making underwater.

Symptoms of Nitrogen Narcosis

• Euphoria: Divers may feel overly happy or invincible, leading to risky behavior.
• Confusion: Difficulty thinking clearly or understanding instructions.
• Poor judgment: Making unsafe decisions, such as diving deeper or ignoring safety protocols.
• Delayed reactions: Slower response times to situations or signals.
• Impaired coordination: Trouble with fine motor skills, like adjusting equipment or swimming smoothly.

Prevention of Nitrogen Narcosis

To avoid nitrogen narcosis, divers should limit the depth and duration of their dives, staying within recreational limits of 30 meters (100 feet). Recreational divers should always monitor their time at depth and ascend immediately if they notice any symptoms may appear.

Using a portable computer can help track depth and time, ensuring divers stay within safe limits. If symptoms occur, ascending to shallower depths will quickly reverse the effects. 

3. Pulmonary Barotrauma

Pulmonary barotrauma is a serious illness that occurs when the lung tissue is damaged due to rapid changes in pressure during a dive.

This happens when a diver holds their breath while ascending, causing the air in the lung to expand and potentially rupture the tissue or force air into the blood vessels, leading to an arterial gas embolism.

This condition can be life-threatening and requires immediate medical attention. Proper breathing techniques and controlled ascents are critical to preventing this injury.

Symptoms of  Pulmonary Barotrauma

• Chest pain: Sharp or intense pain in the chest due to lung overexpansion or damage.
• Difficulty breathing: Struggling to breathe or a feeling of tightness in the chest.
• Coughing up blood: A sign of lung tissue damage or internal bleeding.
• Stroke-like symptoms: In severe cases, air entering the bloodstream can block blood vessels in the brain, causing confusion, paralysis, or loss of consciousness.

Prevention Pulmonary Barotrauma

To prevent decompression injuries like pulmonary barotrauma, divers must never hold their breath during ascent.

Always breathe normally and ascend slowly, allowing the expanding air in the lung to escape naturally. Using a portable computer can help monitor ascent rates, ensuring a safe and controlled return to the surface.

Additionally, divers should avoid dives to a range of depths that exceed their training or comfort level. Proper training and adherence to safety protocols are essential to minimize the risk of decompression sickness and related injuries.

4. Oxygen Toxicity

Oxygen toxicity is a potentially dangerous illness that occurs when a diver breathes high concentrations of oxygen at significant depths. Under increased pressure, oxygen can become toxic to the central nervous system (CNS) or the lungs, leading to serious symptoms.

This condition is more common in technical diving or when using enriched air nitrox (EAN) beyond its safe depth limits. Proper gas management and adherence to depth limits are crucial to avoid this condition.

Symptoms of Oxygen Toxicity

• Visual disturbances: Blurred vision, tunnel vision, or other changes in eyesight.
• Ringing in the ears: A persistent ringing or buzzing sound, known as tinnitus.
• Twitching: Muscle spasms, particularly in the face or hands.
• Seizures: Sudden, uncontrolled movements or loss of consciousness, which can be life-threatening underwater.
• Difficulty breathing: A sign oftoxicity, often accompanied by chest pain or coughing.

Prevention of Oxygen Toxicity

To prevent oxygen toxicity, divers must use appropriate gas mixtures for their planned depth and monitor their oxygen exposure carefully. Avoid exceeding the maximum operating depth (MOD) for your gas mix, as deeper dives increase the risk of toxicity. 

Many divers wear a portable dive computer to track their oxygen exposure and ensure they stay within safe limits. Proper training and awareness of risk factors are essential, especially for those using enriched air nitrox or engaging in technical diving.

5. Barotrauma (Ear or Sinus)

Barotrauma is a common dive-related injury that affects the ears or sinuses due to pressure changes during descent or ascent. It occurs when the fluid-filled spaces in the ears or sinuses fail to equalize with the surrounding pressure, causing pain or damage. While not a decompression illness, barotrauma can be uncomfortable and, in extreme cases, may lead to complications that delay a diver’s return to diving. Proper equalization techniques and awareness of personal health are key to preventing this condition.

Symptoms of  Barotrauma

• Ear pain: A sharp or dull ache in the ear due to pressure imbalance.
• Hearing loss: Temporary or, in rare cases, permanent hearing impairment.
• Sinus pain: Pressure or pain in the sinus cavities, often felt in the forehead or cheeks.
• Nosebleeds: Caused by ruptured vessels in the nasal passages.

Prevention of Barotrauma 

To prevent barotrauma, divers should equalize pressure frequently during descent and ascent. Avoid diving with congestion, as blocked sinuses or Eustachian tubes can trap air and lead to gas bubbles forming in the fluid-filled spaces. If discomfort occurs, ascend slowly to relieve pressure.

Using a decompression table or dive computer can help manage it, reducing the risk of pressure-related injuries. Additionally, divers should avoid flying for at least 48 hours to allow the body to fully recover.

6. Hypothermia

Hypothermia is a condition that occurs when the body loses heat faster than it can produce it, leading to a dangerously low body temperature.

While not directly related to cases of decompression, hypothermia can complicate diving safety, as cold water accelerates heat loss and impairs physical and mental function.

Divers in cold environments must take extra precautions to stay warm and avoid this potentially dangerous condition.

Symptoms of Hypothermia

• Shivering: The body’s natural response to generate heat, often the first sign of hypothermia.
• Numbness: Loss of sensation in the extremities, such as fingers and toes.
• Fatigue: Feeling unusually tired or weak, even after minimal exertion.
• Confusion: Difficulty thinking clearly or making decisions.
• Loss of coordination: Slurred speech, clumsiness, or trouble moving smoothly.

Prevention of Hypothermia

To prevent hypothermia, divers should wear appropriate thermal protection, such as wetsuits or drysuits, to retain body heat. Limit dive time in cold water to reduce exposure, and stay hydrated, as dehydration can worsen the effects of cold.

In severe symptoms, such as confusion or loss of coordination, immediate treatment may be required, including warming the diver and seeking medical attention. While hypothermia itself doesn’t need decompression stops during ascent, it can increase the risk of decompression sickness due to reduced circulation.

Divers should also avoid flying after diving for at least 12 hours to allow the body to recover fully. By staying warm and monitoring their condition, divers can minimize the risks associated with cold-water diving.

7. Seasickness

Seasickness is a common condition caused by the motion of a boat or ship, leading to a disturbance in the inner ear’s balance system. It can affect divers during boat trips to sites, making the experience uncomfortable and potentially impacting their ability to dive safely. Managing seasickness is essential for ensuring a smooth and enjoyable diving trip.

Symptoms of Seasickness

• Nausea: A feeling of queasiness or the urge to vomit.
• Dizziness: A spinning sensation or loss of balance.
• Vomiting: Expelling stomach contents due to severe nausea.
• Sweating: Excessive perspiration, often accompanied by cold, clammy skin.

Prevention of Seasickness

To prevent seasickness, divers can take anti-motion sickness medication before boarding the boat. Staying on deck for fresh air and focusing on the horizon can help stabilize the inner ear’s fluid balance and reduce symptoms.

While seasickness itself doesn’t involve bubbles may forming in the body, it can make divers feel unwell and less alert, which could likely to cause decompression sickness if they dive while feeling ill. By managing seasickness effectively, divers can ensure they are in the best condition to enjoy their underwater adventures.

Conclusion

Understanding diving illnesses and their prevention is key to a safe and enjoyable underwater experience. By following proper dive practices and diving with professional guidance, you can minimize risks and focus on exploration.

For a worry-free adventure, choose Spirit Liveaboards, offering luxury diving experiences in the Maldives and Fiji. With expert guides, personalized service, and a focus on safety, they ensure you explore the best dive sites in comfort and style. Dive with Spirit Liveaboards for an unforgettable journey!