Free divers are able to explore the depths of the ocean without the risk of decompression sickness, commonly known as “the bends.” But how do they manage to avoid this potentially life-threatening condition?
How Do Free Divers Not Get The Bends?
Free divers typically don’t need to be concerned about decompression sickness, commonly known as “the bends”, as they are not inhaling compressed air underwater. They simply draw a breath at the surface, descend, and then return to the surface without taking another breath. Everything returns to normal as they aren’t underwater long enough for it to become an issue.
Scuba divers, on the other hand, breathe compressed air underwater, which means they intake more air particles than they would at the surface. The deeper the dive, the more air particles are inhaled, most of which are nitrogen molecules. While our bodies don’t use nitrogen for anything, it does dissolve into our body tissues under increased pressures.
The deeper we go, the more molecules our bodies can store until we reach a point of saturation. Upon returning to the surface, these nitrogen molecules must exit our body tissues because we’ve become overly saturated with nitrogen. If they leave slowly, there’s no harm done, which is why divers are instructed to ascend slowly. However, if the molecules leave too quickly, bubbles can form within the body, leading to the bends.
Free divers avoid becoming overly-saturated with nitrogen as they do not breathe compressed air underwater, and their time underwater isn’t sufficient for their body tissues to reach saturation. However, if a free diver were to breathe from a scuba diver’s alternate air source before ascending, they could potentially suffer from decompression sickness due to the brief exposure to compressed air.
More likely, they risk a lung over-expansion injury if they hold their breath while ascending after breathing compressed gas, as the gas expands when pressure decreases. The most common lung over-expansion injury is an arterial gas embolism, which could be immediately fatal. Hence, scuba divers are trained never to hold their breath but to breathe continuously – this is the most crucial rule in scuba diving.
It’s theorized that blue whales could potentially suffer from the bends since they can remain deep underwater for extended periods. The nitrogen in the air they breathe at the surface could theoretically be stored in their body tissues, and upon surfacing, that nitrogen could exit their tissues and form bubbles. However, this remains a theory. For humans, breath-hold dives generally don’t pose a risk of decompression sickness.
Does free diving give you the bends?
How divers prevent the bends?
In short, the answer is Yes. However, to run the risk of decompression sickness, you would need to undertake a significant number of shallow dives with minimal surface intervals over a prolonged period. I’ve heard from some spearfishing friends who experienced the bends after an 8-hour spearfishing trip, diving to depths of up to 20 meters. They likely developed decompression sickness because they didn’t spend enough time on the surface between dives.
On the contrary, if you were to be snorkeling around a reef at say, 5 meters, it would be highly unlikely to develop decompression sickness. This is simply due to the immense volume of diving that would be required.