Various studies have been conducted to see how freediving affects the brain. They are not all conclusive. The results vary by experience and type of freediving. Some studies suggest that long-term breath-hold diving can cause brain damage. Others suggest that it has no negative effects on the brain. Regardless, the risks of freediving include decompression sickness, nitrogen narcosis and barotrauma.
A recent study conducted at Lund University in Sweden found that breath-hold freediving may cause mild neurological dysfunction. The researchers conducted a study on nine competitive freedivers and six non-freedivers. They took arterial blood samples before and after the breath hold. They measured the amount of oxygen in the blood. They also looked at the heart and respiratory rate.
The arterial blood samples were taken from a catheter inserted into the wrist artery. The researchers found a small spike in the S100B protein level after the breath-hold. The levels quickly dropped. This protein is associated with brain damage. It was also observed in other sports. The researchers recommend that more studies be done to better understand the effects of freediving on the brain.
Another study was done on an elite group of freedivers. The participants reached depths of 107 meters. Their heart rates were similar to that of seals and dolphins. The study found that the participants had lower oxygen levels in their brains than seals and dolphins. They also performed slightly worse in memory tasks.
In addition to the cardiovascular effects of breath-hold freediving, a study has found that it may also cause hypoxia. Hypoxia is when there is a decrease in the flow of oxygen to the brain. This can lead to seizures and other physiological changes.