It’s possible to die just by holding your breath too long while submerged in water. Referred to as shallow water blackout, the condition impacts those that are in the swimming and diving industry.
Read on as we’ll deep dive into the signs and symptoms of someone suffering from underwater blackout, and how you can prevent it and ensure your safety in the water.
What is Shallow Water Blackout?
Shallow water blackout isn’t necessarily drowning or spearfishing in shallow water. The loss of consciousness occurs while underwater, typically caused by the lack of oxygen in the brain (often done intentionally).
Holding one’s breath underwater is practiced by professional and beginner swimmers alike. The ultimate result can be death, which is why it’s very important that you’re educated on the dangers of avoidable affliction.
Whether you’re swimming in a swimming pool, river, lake, ocean, or even a bathtub, you’re susceptible to experiencing shallow water blackout. The majority of the cases were due to breath-holding contests and underwater distance swimming.
Underwater Blackout Causes, Signs, and Symptoms
In the normal breathing process of humans, carbon dioxide is incredibly important as it’s what triggers a mechanism that tells our bodies to breathe.
Rather than a lack of oxygen, carbon dioxide rise is what’s monitored by our chemoreceptors which signal our brains when exactly to breathe.
Most divers and spearfishermen are familiar with oxygen’s characteristics: tasteless, odorless, colorless, and found in our atmosphere. Most can maintain the proper blood oxygenation, which is at 16 percent. Unconsciousness results when the oxygen level of a person drops to 10 percent.
A state in which there aren’t sufficient amounts of oxygen at the tissue level necessary in maintaining adequate homeostasis, hypoxia is accompanied by the following symptoms:
| Oxygen Percentage (%) | Hypoxia Signs and Symptoms (at sea level) |
| 15 to 19% | Fatigue, headache, dizziness, impaired judgment, rapid breathing |
| 12 to 14% | Respiration increase, impaired coordination, fatigue, increase in pulse rate |
| 10 to 11% | Unconsciousness, nausea, cyanosis, mental failure |
| 6 to 8% | 100% fatal after 8 minutes, 50% fatal after 6 minutes, recovery is possible with treatment after 4 minutes |
There are divers that experience a sensation of heat, a sense of euphoria, tunnel vision, dizziness, and lightheadedness. During unconsciousness, divers may continue swimming or kicking as muscles in their extremities still have the ability to anaerobically function.
Typical divers may begin a dive with a lactic acid of 9 percent in the extremities. After a full minute of holding the breath and reaching 90 ft of seawater, it could easily rise to more than 50 percent.
This is why it’s incredibly important to have a dive buddy to note the angle or altitude the diver is coming up from and not just if the person is kicking. Unconscious divers can veer off one side or begin sinking again towards the bottom.
How to Prevent Shallow Water Blackout
Keep these best practices for underwater blackout prevention:
Never Hyperventilate Excessively
Keep it to a maximum of four breaths. A deep and slow relaxation kind of breathing that’s used in yoga is best rather than hyperventilation. Your ability to relax will be crucial when holding your breath.
If you hyperventilate in the water, it’s a lot more dangerous compared to hyperventilating on land. As you’re accelerating your breathing, you’ll gasp for air.
Because you’re submerged, water will go inside your airway and your lungs. This makes drowning a possibility.
Be More Efficient When Underwater
Breath-holding time in the water is entirely dependent on the oxygen that’s in the last inhale we make at the water surface. It’s, therefore, crucial to limit oxygen consumption.
What this means is to move underwater efficiently and effortlessly. Every action you take must have a particular reason, otherwise, you’ll be wasting precious oxygen in your body.
Remember that all body movements need oxygen. Our thigh muscles are some of the largest muscles in our bodies and they require a lot more oxygen compared to other muscles.
Pull or glide whenever possible. Keep the drag of your body down and make sure your swimming profile is sleek. This will maximize the distance covered for each effort.
Rest in Between Dives
Rest in between dives and continue breathing slowly. Slow, deep breathing will flush out lactic acid and wastes properly as they accumulate from a dive.
Take your time when preparing yourself for your next dive. The general rule is to rest 2x the total duration you spent underwater. If you completed a 1-minute and 30-second dive, for instance, spend at least 3 minutes resting at the surface before you do your next dive.
Violating the rule won’t only penalize your body and efficiency underwater during the next dive, but you’ll also put yourself at risk of experiencing a shallow water blackout.
As your fitness and experience progress, your surface time can be shortened. Still, you should remember that excessive movement or exercise underwater e.g. fighting against strong currents or struggling with fish can be very deadly to freedivers.
Conclusion
When diving, make sure that you have a buddy with you. This applies to even the most skilled and experienced divers. If visibility permits, you and your diving buddy should alternate your dives. You should also keep an eye on one another, most especially if you’ll be reaching deeper into the water.
Take note: deep is relative. For some, it can be 50 ft while for others 80 ft of seawater is deep. For us, a dive is deep when we reach a depth where a bit of apprehension will come into mind plus you keep on checking your body for comfort.
In deep water, if you’ll be holding your breath for two minutes or more, it’s a must to have a dive buddy with you. It’s impossible to overstate how dangerous it is to experience shallow water blackout.
Spread the word regarding the matter, most especially to your family and friends who spend lots of time in the water as you might just save their lives.
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