Is Scuba Diving Dangerous? Everything You Need to Know

The underwater world is a magical, fascinating place and diving is exploring it at its finest. However, we hoo-mans are land animals and we aren’t meant to be breathing, swimming, or seeing underwater, which is why we need equipment such as regulators and masks to help us do so.

In addition, there are several strict rules you’ll have to follow while diving as our bodies aren’t made to tolerate dramatic pressure changes or being at depths for prolonged periods.

So is scuba diving inherently dangerous? The good news is that diving is a relatively safe activity that millions enjoy every year. From children as young as eight to seniors with limited mobility, it is a sport that carries far fewer risks than others. 

That being said, any sport has risks and scuba diving is no different. In this blog post, we’ll look at all the risks associated with scuba diving and share what you can do to mitigate them. 

Prohibition Sign by the Lake

What are the Risks of Scuba Diving?

The most common medical problems that scuba divers can suffer from are sunburn, seasickness, and dehydration, which are all minor conditions that can arise from prolonged sun exposure. With proper care, these minor problems can be easily avoided.

However, there are also the more serious conditions that can arise from a dive itself like decompression sickness, or the “bends”. These conditions are exceedingly rare and account for only a fraction of emergency room visits each year. With proper training and preparation, they too, can be avoided. Here are some of the major risks of scuba diving but remember, they ARE rare! 


Drowning is the number one cause of fatal diving accidents, even though decompression sickness, or DCS, is more common. Drowning can occur several ways but is usually due to a pre-existing medical condition or diver error. 

For example, the Divers Alert Network (DAN) reports that 25% of all fatalities come from older divers with pre-existing heart conditions. In addition, 41% of fatalities happen because of insufficient air. 

Regardless of age, you should always check with a medical professional before you dive if you have a medical condition. Dive operators also administer a health questionnaire before they allow you to dive with them so fill it in honestly. Practice hand signals and handling an out-of-air emergency situation with your buddy before you descend, and check your air frequently during the dive. 

Decompression Sickness

Decompression sickness (DCS) is commonly known as the bends, and it is the most commonly known dive injury. This is primarily caused by the inability of our bodies to quickly process nitrogen, unlike oxygen which our bodies can easily metabolize. 

We breathe air at the surface in a mix of 79% nitrogen and 21% oxygen. That’s fine, and our bodies are adapted to that. The surface pressure is one atmosphere, also called 1 bar. When you descend to 10 meters, that pressure becomes 2 bar, which means it doubles. 20 meters, and it is 3 bar, and 30 meters, it is 4 bar. You get the idea. 

That means that at 30 meters, your body is absorbing four times the nitrogen from the air you breathe which comes from the tank on your back. (or on your side!) That nitrogen is stored in your joints, tissue, and muscles. 

Staying at depth, the nitrogen is compressed and remains at that specific pressure. The problem arises when you ascend. The pressure decreases, air starts to expand, and the excess nitrogen in your body can form bubbles in your tissues. This is DCS, and it can cause pain, damage nerves, joints, and tissue. 

DCS should not be left untreated and a trip to a hyperbaric chamber is definitely a good idea. The air in the chamber will be pressurized to shrink the bubbles, then the pressure very slowly changes to allow your body to process the nitrogen. DCS is seldom fatal, but it is STILL a possibility. 

Photo of a Person Snorkeling

Arterial Gas Embolism

Rule number one of scuba diving is that you never hold your breath while ascending. The second rule is to slowly ascend from every dive. A violation of either of these rules could lead to a condition called arterial gas embolism, or AGE.

As mentioned before, you’re breathing loads more air at depth than you would on the surface. If your lungs are filled with air and you ascend too quickly, the rapid pressure change can cause bubbles to form in an artery and restrict blood flow to your vital organs, brain, or spinal column. 

This is called barotrauma, which is an injury due to pressure. AGE is an extremely serious condition that needs immediate medical attention. To avoid this dangerous situation, observe the first two rules of scuba diving religiously and you should be golden! 

Oxygen Toxicity

Although our bodies can process oxygen way more efficiently than nitrogen, O2 is still toxic at high levels. The partial pressure of oxygen increases greatly as you descend, and prolonged exposure can give you symptoms such as convulsions, flashing lights, tunnel vision, ringing in the ears, confusion, nausea, and numbness or tingling. 

Oxygen toxicity is more common with divers that use different air mixes such as Nitrox, which has a higher percentage of oxygen. Divers use Nitrox to extend their bottom time as a lower nitrogen level means less residual nitrogen and less risk of DCS. 

If you exhibit mild non-convulsive symptoms, ascend to a shallower depth or end the dive. Oxygen toxicity itself isn’t often fatal, but complications can occur if a diver convulses underwater and loses his or her mouthpiece. 

Nitrogen Narcosis

Nitrogen narcosis can happen when you descend too quickly, especially at depths of 30 meters or more. This temporary effect is a result of a rapid increase in nitrogen in your bloodstream which can cause a feeling of intoxication. Narcosis on its own is seldom serious, but when intoxicated, your judgment may be impaired and you might make poor decisions. 

To avoid this, descend slowly and watch carefully for signs of dizziness or other strange feelings. If you’re feeling the effects, simply ascend to a shallower depth and the feelings should pass. Watch your buddy closely for signs of intoxication as well and be prepared to administer help if needed. 

Marine Life

The underwater world is a fascinating one but like any environment, it contains animals that can cause injury. No, we aren’t talking about sharks here. Sharks are typically docile animals that want no trouble from you, but touching or chasing them is never a good idea. Any animal will attack if they feel threatened. 

Worry more about the spiny Lionfish, super poisonous Stonefish, stinging coral and venomous jellyfish instead. Be sure to practice good buoyancy control and stay off the ocean floor. Also, wear a wetsuit to protect your skin from accidental contact, even in warmer waters.  

Black and White Turtle

Pre-Existing Health Conditions

Some pre-existing health conditions can make diving tricky. For example, we mentioned heart conditions earlier. If you have any medical conditions, be sure to clear it with your doctor before you go on that dive trip. 

Most dive operators will also require you to fill out a health questionnaire prior to diving. Answer it truthfully and NEVER lie. If you feel that your medical condition might prevent the dive op from allowing you to dive, get your doctor to sign a health certificate that clears you to dive prior to your trip. 

Do People Die Scuba Diving?

Unfortunately, yes. Any activity in a natural environment carries inherent risks that can never be fully avoided. According to DAN America, there are 16.4 deaths per 100,000 persons annually. This is comparable to the 13 out of 100,000 deaths for jogging, and 16 per 100,000 for driving a motor vehicle. 

86% of the cases were divers that got separated from their buddy or diving alone. The key to a safe dive is to follow your guide’s instructions, stick to your buddy, and observe lost buddy procedures if you happen to get separated. Never continue the dive if you’re separated from your buddy! 

Always plan the dive and dive the plan. Dive within your training and ability and don’t bite off more than you can chew. Some dive sites might be more challenging than others, requiring a rapid and deep descent, or battling strong currents that can be unpredictable. These sites are a big no-no for beginners and many dive operators won’t take you if you have under a certain number of logged dives. 

Always get local knowledge if you are planning an independent dive with your buddy, and when in doubt, hire a dive guide. 

Diver in wetsuit swimming near shark underwater

Final Thoughts

Diving is a fun, enriching activity that can be enjoyed by people of all ages. However, the underwater world, however fascinating, is still a natural environment and the big blue ocean is mighty. 

Stick within your dive training and limits and always respect the power of Mother Nature. Stay safe out there and happy diving!

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