Many repeated free dives can cause TARAVANA wich is a decompression accident.
This happened in oesters divers from the Touamotu islands whisch where free diving 20 to 40 metres.
Taravan can be mild : vertigo, vomiting,nausea
can be serious: neurologic symptoms
sometimes it can leed to death mainly by drowness.
The serious symptoms will releave within 24 to 48 hours in 95% of the cases, somethimes lasting for a few days.
The symptons relate more a cortical lesion than a spinal cord lesion, because the symptoms are often unilateral.
Psychological symtoms may also occure such as the boxer's " punch drunk ".
Donnet, Coriol, Millet (1954) seem to think that this accident might be relating to bubble formation within the short half period tissues mainly the blood.
Those bubbles will embolise in the terminal vascularisation of the brain causing symptoms.
The number of molecules of N are constant , but the O2 is used and the CO2 if fixed within the blood, so the ppN ( partial pressure of nitrogen N) is rising within the pulmonary alveoles causing dissolution of Nitrogen in the schort half time tissues such as blood
Tarravana occure while executing many repetitive ( more tha 15 dives/hour for 6 to 10 hours ) add to this a fast ascend and co2 liberation from where it was fixed and you might have a Tarravana.
Dont forget about schallow water black out due to important hyperventilation and low ppCO2 before diving
Ear barotrauma might occure if diving very deep because the volume of air is so reduced that you won't have air enough to ba able to compensate rising pressure.
If going to deep too fast you might experience a blood pooling within the lungs, no more blood will fill you left cardiac cavities and the result is cardiac arrest.
Sorry for my written English
Fa
