Introduction
If you talk with someone who has never held their breath for minutes at a time, or dove to depths greater than the bottom of a pool, they may ask “ is freediving bad for you?” The answer to that question is not always straight forward.
As with any extreme sport, those practicing freediving improperly or without proper training can get hurt. There are a number of avenues for the average person to get seriously injured or even killed.
Some dangers are more prevalent than others. As a sport practiced in uncontrolled environments, there are elements of risk that cannot be reduced. Just like surfing, snowboarding and other extreme sports taking place in nature, things can be very unpredictable.
In this article, Free Depth will illustrate some of the possible avenues that freediving can cause harm to you if you do not safely practice the sport.
*Disclaimer* Get training! Freediving is an extreme sport and you should be wary of attempting it without proper training. Never dive alone, it can mean the difference between a trip to the hospital and a trip to the morgue.
Freediving can cause pressure related injuries
Pressure related injuries, known as squeezes, are one of the most common types of injuries in the freediving community. It is not uncommon to see competitive freedivers return to the surface with a bloody nose. This is an example of a pressure related injury.
A squeeze occurs when a freediver is unable to properly equalize to the water pressure at a given depth. A squeeze is a type of barotrauma, an injury caused by pressure.
Lets use mask squeeze as an example. You are diving to a target depth of 20 meters, at that depth you are looking at a pressure equivalent to 2 times the atmospheric pressure at sea level. As you dive, more and more pressure is exerted on your mask and the air trapped inside it. If you are unable to equalize the pressure, it results in a negative pressure inside your mask. This difference in pressure can result in injury to blood vessels of the eyes, nasal passages, face and periorbital regions.
Freediving Can Lead To Hypoxia
Blackout
One of the most dangerous things that can happen while freediving, and something that will make many people ask “Is freediving bad for you?”, are shallow water black outs.
A shallow water black can occur after deep dives due to the effects of pressure on gas exchange in the lungs. During the ascent from a deep dive, the air in the lungs expands as hydrostatic pressure decreases. As the air in the lung expands it can cause a decrease in alveolar oxygen pressure, causing an inversion of oxygen flow. This decrease in oxygen pressure can result in rapid drops in specific oxygen levels in the lungs and blood leading to increased risks of near surface hypoxic blackouts.
Hypoxia
The primary driver among mortality in freedivers, especially spearfisherman or those with less training is hypoxia. Hypoxia is essentially a lack of sufficient oxygen. While the repeated hypoxia due to freediving’s effect on the brain is not yet understood, the effects of hypoxia alone are. Generally, two minutes after loss of consciousness due to hypoxia brain damage will begin to occur.
Symptoms of Hypoxia:
- Loss of consciousness
- Blue or white lips, tongue, face
- Tingling in the extremities
- Non normal pupil dilation
- Gasping for air
One sure fire way to INCREASE the risk of hypoxia is to hyperventilate before a dive or breathe hold. DO NOT HYPERVENTILEATE BEFORE A DIVE. The reason it increases the risk of hypoxia is due to CO2 in the blood and tissue. It is CO2 level and not O2 levels that are responsible for the bodies urge to breath. Hyperventilating reduces CO2 stores in the blood and thus reduces the reflex to breath and reduces the forewarning before a blackout (Craig).
Carbohydrate Depletion
A less well-known danger of repeated and intensive dives is carbohydrate depletion. Once carbohydrate stores have been depleted due to diving activities, the body begins to burn fat. Burning fat reserves use 8% more oxygen than metabolizing carbohydrates. It has also been found that 30% less CO2 is produced by the metabolization of fat. As such, after a day of strenuous activity, a dive that may feel fine early in the day becomes dangerous. The body will use its oxygen reserves faster and the decrease in CO2 generation will decrease the respiratory stimulus to breath caused by hypoxia, possibly leading to blackout or loss of motor control (LOC).
Ocean related Freediving hazards
Temperature
As with any extreme sport, you need to be prepared for the conditions. The water temperature plays a huge role in what equipment you need to use in order to make sure your freediving isn’t bad for you.
If water temperatures are too low, or if you don’t have the proper equipment, a freediver may experience hypothermia. Clinical hypothermia is when the body’s core temperature drops below 35 degrees Celsius. Leaner divers are particularly susceptible to hypothermia as they have less subcutaneous fat to act as insulation.
It is important that all freedivers recognize the signs of hypothermia in themselves and their diver partners. Due to possible distance from shore or a safety boat, early detection of hypothermia is paramount to diver safety.
Symptoms of Hypothermia:
- Shivering
- Slurred speech
- Clumsiness
- Weak pulse
- Lack of coordination
- Memory loss
- Dizziness
- Redness of the skin
- Loss of consciousness
If you or your dive partner is suspected of having hypothermia, end the dive session immediately and leave the water as soon as possible.
Water Inhalation
As a water-based sport the final danger we will explore in this article is water inhalation. The reason you are not supposed to dive with a snorkel still in your mouth is to avoid the accidental inhalation of sea water in the event of a black out.
When you inhale seawater you can include both acute lung injury ( ALI) and acute respiratory distress syndrome (ARDS). Seawater, even when seemingly coughed up causes residual damage to the lungs for hours after the event. ALI occurs due to the inflammation caused by seawater inhalation can result in respiratory failure. As such, if you or a dive partner are suspected of inhaling seawater, it is crucial to end the dive session and seek medical assistance. The danger posed by sea water inhalation does no pass until several hours after the event.
Conclusions
Just like any other extreme sport, if you are not prepared or try to go to far beyond you limits, freediving is bad for you. However, it does not have to be. With proper training, technique and knowledge, a freediver can safely descend to incredible depths without suffering any deleterious effects.
While there are possible negative effects to health caused by freediving, there are also positive health outcomes associated with freediving and freediving training. Free Depth will explore these positive outcomes in a future article.
As always, respect the ocean, have fun, dive safe!