Free-diving is any of various aquatic activities that share the practice of breath-hold underwater diving. Examples include breathhold spear fishing, free-dive photography, apnea competitions and, to a degree, snorkeling.
The activity that garners the most public attention is competitive apnea, an extreme sport, in which competitors attempt to attain great depths, times or distances on a single breath without direct assistance of self-contained underwater breathing apparatus (scuba).
It is a technique used with various aquatic activities. While in general all aquatic activities that include breath-hold diving might be classified as a part of it, some sports are more accepted than others. Examples of recognized this activities are (non-) competitive, (non-) competitive spearfishing, photography and mermaid shows. Less recognised examples include, but are not limited to, synchronised swimming, underwater rugby, underwater hockey, underwater hunting other than spearfishing, and snorkeling.
The discussion remains whether it is only a synonym for breath-hold diving or whether it describes a specific group of underwater activities. This is often strongly associated with competitive breath-hold diving or Competitive Apnea.
It is also an intriguing recreational sport, celebrated as a relaxing, liberating, and unique experience. Many snorkelers may technically be free-diving if they perform any sort of breath hold diving - it is important to stress the importance of training and supervision when making this association.
Like other water sports, it is associated with therapeutic properties. The experience of freedom in an underwater environment makes it somewhat of a personal and spiritual journey for many. Yoga is used by many practitioners to increase focus, breath, and overall performance. The 'art' of free-diving and the practice outside the athletic and competitive sphere goes beyond the scope of this article.
Training for this type of dive can take many forms and be done on the land.
One example is the apnea walk. This consists of a preparation "breathe-up", followed by a short (typically 1 minute) breath hold taken at rest. Without breaking the hold, the participant then initiates a walk for as far as they can, until it becomes necessary to breathe again. Athletes can do close to 400 meters in training this way.
This form of training is good for accustoming muscles to work under anaerobic conditions, and for tolerance to CO2 build-up in the circulation. It is also easy to gauge progress, as increasing distance can be measured.
In 2004 a club based in London (NoTanx) started to develop the first complete training system. Lead by Marcus Greatwood who coached several world records and many national records completed the system in 2009. They claim that The NTStyle includes Neurological programming, physical and mental training.
Before dive, performance-oriented free-divers hyperventilate to a certain degree, resulting in a lower level of CO2 in their lungs and bloodstream. This postpones the start of stimulation to the breathing centre of the brain, and thus delays the warning signals of running out of air. As the oxygen level of the blood is not increased by hyperventilation, this is very dangerous and may contribute to shallow water blackout and deep water blackout. Trained divers are well aware of this and will only dive under strict and first aid competent supervision.
However this does not, of itself, eliminate the risk of deep or shallow water blackout. All safe free-divers have a 'buddy' who accompanies them, observing from within the water at the surface. Due to the nature of the sport, safety is an integral part of
free-diving,
requiring participants to be adept in rescue and resuscitation. Without proper training and supervision, apnea/breath-hold diving is extremely dangerous.