During freediving, there are many hazards. The main dangers are lack of air and hypoxia. These can be fatal when diving alone. There are also environmental hazards. These may be specific to the site or the time of the dive.
The best practice for freediving is to always dive with a trained partner. Depending on the depth of the dive, this can include a safety diver. A safety diver will hold the line while the freediver ascends.
The best practice for breathing is to breathe naturally and calmly. You can also lengthen your exhale. This will help relax your heart and slow your breath rate. During freediving, you should not test your eardrum’s strength. If you do, it can damage the eardrum.
Full exhalation diving can also be dangerous. This is because the weight of the water compresses air in the middle ear. This can be painful, leading to micro-trauma.
Another danger of full exhalation diving is lung barotrauma. This is when the air in your lungs is squeezed. This may be caused by an overly aggressive exhale.
For the best safety measure, it is recommended that you do not attempt to go deeper than 15 meters. This does not sound like a difficult challenge, but it can be a dangerous one.
It is also recommended that you perform equalization before diving. This will help maintain proper buoyancy and prevent hypoxia. When a freediver dives too deep, he or she may be forced to take too many short breaths during ascent.