Quiz - Physiology - Tight Neck Seal or Hood

[Pedro Burrito]

From the Physiology Section of the PADI Dive Theory Exam:

If a diver wears a suit with an excessively tight neck seal or hood, he/she may risk unconsciousness due to ___. This is called ___.

a. excessive CO2 levels / shallow water blackout

b. low CO2 levels / hypocapnia

c. low O2 levels / hypoxemia

d. reduces blood supply to the brain / carotid sinus reflex ​

I will post a daily question from my exams to help newer divers and to encourage more experienced divers to interact gracefully and helpfully with the newer divers.

Reminder - this is a post in the Basic Forum and it is a green zone. Please be nice and on topic.

Thank you for your patience while we try to give people something to discuss other than Covid-19 and/or Politics. I will post the answer covered by the spoiler tag later today.

 

[Storker]

This question is very relevant for us dry suit divers. If our neck seal is too loose, we get wet, and if it's too tight we risk blacking out. Which would be more than a mite inconvenient...

 

[Edward3c]

A number of times I've had to teach new divers about hoods being too tight. If water doesn't get into the outer ear they have a risk of reversed ear damage. The pain before the ear drum goes is quite extreme - I don't know how people can just ignore it.

 

[Storker]

A number of times I've had to teach new divers about hoods being too tight. If water doesn't get into the outer ear they have a risk of reversed ear damage.

At the beginning of my descent I always make sure to stick a finger inside my hood on both sides, to let water into the hood and into my ear canals. Works even on thick, very snug winter hoods

 

[Frackingawesome]

I was really looking for a shrunken head syndrome... guess i was wrong.

 

[Jcp2]

Right thought. Wrong head.

 

[Scared Silly]

I was really looking for a shrunken head syndrome... guess i was wrong.

I was thinking more in line with an exploding head. The heart is pretty good at pumping blood even where there is a constriction. But the return is not so good. So I figure there would be an excess amount of pressure and boom, a headless diver.

 

[CaveSloth]

If water doesn't get into the outer ear they have a risk of reversed ear damage.

I cut ear holes in my hood because it felt weird without them.

 

[TMHeimer]

Yes water gets in the ears with a properly fitting hood. When donning fins in the water and tipping to my side, it sometimes goes WAY in. I raise head out of water and pull hood side out to let the water drain out of my ear. I would not consider cutting ear holes. My feeling is the hood does the same job as "Doc's Pro Plugs" by keeping water from going deep into the ear. I've never had any ear problems.

 

[Marie13]

At the beginning of my descent I always make sure to stick a finger inside my hood on both sides, to let water into the hood and into my ear canals. Works even on thick, very snug winter hoods

Yep, I do this as well.