doole:
In the last year or so, I have experienced mild vertigo when teaching in the pool, specifically when proceeding to the surface at the point when the top of my head is within a foot or so of the surface. The vertigo is mild but certainly noticeable. It vanishes when my head breaks the surface.
I have never noticed this in open water.
What could it mean? TIA chris
Only in the pool? Curious.
Is it true vertigo, or dizziness? Vertigo specifically refers to an induced sensation of spinning or rotation.
There are many possible causes of vertigo for divers. From this excellent site:
http://www.scuba-doc.com/vert.htm
>>It can be caused by decompression sickness, hypoxia (low oxygen), hypercarbia (high carbon dioxide), nitrogen narcosis, seasickness, alcoholic hangovers, sensory deprivation, hyperventilation, impure breathing gas, unequal caloric stimulation (as with one ear blocked by wax), and difficulties with middle ear pressure equalization (forcible Valsalva with blowout of the round window and inner ear damage)".
You can immediately exlude many of these causes.
But this:
>>Transient vertigo almost always is due to " alternobaric vertigo " due to unequal middle ear pressures during ascent with resultant unequal vestibular end-organ stimulation. Pressure differences as little as 20 mm Hg can produce this in the chamber. Approximately 15% of all divers have been shown to have experienced this type of vertigo at some time in their diving careers. (Pullen)".
>>This same type of vertigo can be produced by unequal caloric stimulation of the eardrum, as with colder water entering the undermost ear in the prone position. An external ear partially blocked with wax can cause this inequality".
But why in the pool but not in the ocean? I don't know. Maybe you wear a hood in the ocean but not in the pool? That might make a difference.
It would be worthwhile having a medico take a look in your ears.
