During a freedive, the freediver moves vertically through the water column. During this process, the partial pressure of oxygen changes with the ambient pressure, and microbubbles expand.
Freediving is not without risks. A lack of oxygen can lead to hypoxic syncope, known as the “blackout” by divers. While a few experienced freedivers have been known to dive to more than 60 feet (18 meters), two have died while trying to achieve this goal.
It has been estimated that the average person can go three minutes without oxygen. This is not a good idea, however, since it can lead to brain damage.
A good rule of thumb is to only dive deep to about 20 feet (six meters) unless you are an experienced freediver. Freediving to depths of 40 feet (12 meters) and above requires a bit more caution and a lot of practice.
The safest depth for freediving is a bit of a controversial topic. Some freedivers believe that it is safest to go no deeper than 100 feet, while others think that it is safer to dive to 65 feet (20 meters). Despite these differences, no one can say for sure. It is better to follow the rules, stay calm and practice holding your breath for long periods.
If you do decide to dive to greater depths, you need to have a good freediving recovery system. This includes a freediving buoyancy device, a freediver’s helmet and a freediver’s recovery lanyard.