Free Diving

Free diving refers to a range of sports that involve holding the breath for long durations while underwater. The scientific term for holding your breath is apnea. According to AIDA, the international free diving governing body, free diving can be split into the following disciplines.

  • Static Apnea (STA). Is a competitive sport where the objective is to hold ones breath for as long as possible while remaining immobile, it is usually performed in a swimming pool. A freediver must respond to hand signals when prompted in order to demonstrate that they are still conscious.
  • Dynamic Apnea. Is where freedivers compete on distance swam underwater on a single breath. There are two varieties of dynamic apnea – with the aid of swim fins (DYN) and without the aid of swim fins (DNF).
  • Constant Weight. A freediver must descend to his personal maximum point as marked on a rope and ascend again without the use of propulsion equipment or by touching the rope. There are two types, with the aid of swim fins (CWT) and without (CNF). CNF freediving is considered by many to be the most difficult form of free diving as the diver must ascend using his only his own strength and skill. He must attain a near perfect balance of buoyancy control, pressure equalisation techniques and swimming.
  • Free Immersion (FIM). Here a free diver descends to his maximum and ascends again by pulling on the rope. It is a free diving discipline much loved by purists due to the lack of external assistance in achieving great depths. Competing free divers can choose to travel down the rope head-first or feet-first, some like to use a combination of both.
  • Variable Weight (VWT). In VWT a free diver descends using ballast and ascends by pulling himself up on the rope. Sleds make also be used to take a diver down to great depth at speed, they can descend head first or feet first.
  • No Limits (NLT). No limits free diving is the most extreme and controversial form of free diving. A free diver descends and ascends using whichever method he desires. Ballast, sleds, fins and inflatable balloons for ascent are all options. The only idea is to dive as deep as possible. The world record for a no limits free dive is held by Herbert Nichst who descended to 214 metres in 1997 in Greece. He holds the coveted title of being the world’s deepest man. The world’s deepest woman title is held by Tanya Streeter of the Grand Cayman Islands who achieved a no limits depth of 160 metres. She had previously broken several male records and is known to be able to hold her breath for up to six minutes!
  • Snorkelling is also considered part of free diving as it is carried out without the assistance of breathing apparatus. Snorkelling can be considered good training for potential scuba divers as one gets to feel comfortable in a marine environment. Greater depths with more interesting marine life can be reached by snorkellers as they learn to hold their breath for longer and equalise.
  • Spear Fishing. In many countries it is illegal to hunt with a gas propelled or mechanical spear gun while using an underwater breathing apparatus. Therefore spear fishing officially comes under the category of freediving. A spear fishing diver usually makes use of a snorkel, dive mask, knife and sometimes flippers to navigate a depth range of around 0 – 20 metres in search of his prey. Bluewater spear fishing is an extreme variant of the sport, where big ocean going species such as Tuna and Marlin are attracted with the addition of chum (chopped up fish pieces). Shark attacks are a risk in water where blood from speared prey or chum drives them into an uncontrollable feeding frenzy.

There exists in the human body a set of automatic reflexes to extreme pressure known collectively as the mammalian diving reflex. Without these, humans would not be able to survive underwater at the extreme pressures. Here are the amazing changes that occur as the human body descends in depth.

  1. The heart slows by about 20%. The need for oxygen is thus diminished.
  2. Blood vessels and capillaries in the limbs constrict to force blood away from the extremities and around the vital organs, especially the brain.
  3. Blood plasma fills the lungs making them resistant to collapse. Without this the lung walls would collapse due to external ambient pressure, resulting in permanent damage.

Free diving carries with it a number of risks related to extreme depths and oxygen starvation in the brain. Deep and shallow water blackout in particular have caused a number of deaths and the latter has occurred in youngsters playfully competing in swimming pools. The scientific community notes that the maximum limits of endurance have already been reached by freediving record holders and any further attempts to exceed these will result in serious brain injury and/ or death.