Nitrogen Narcosis Tolerance?

Hello,

Can you build a tolerance for nitrogen narcosis or is it a fixed phenomena?

Any thoughts are greatly appreciated,

Safe diving.

I understand that part of your susceptability to Nitrogen Narcosis is psychological, so you can lessen its effects by being able to recognize the symptoms.

Whether you can actually modify your physiological response is beyond my expertise by miles...

No. The only thing you can "learn" is to delude yourself into thinking you're not narced.

The issue has been covered in many posts available by using the search button.

MD

Thanks for the advice.

I will perform a search and see what I can find. I guess I should have done that in the first place!!

Safe diving.

I posted some exerpts from a few studies a while back. Studies show that you can learn to compensate when performing certain types of tasks. By compensate I mean trading speed for accuracy or accuracy for speed or just being more focused on the task. The studies also show that what you can't learn to do while narced is think. Therefore there isn't anything you can really do to prepare to handle new problems or those which require reasoning ability in order to develop a solution.

Just like with drinking, the argument isn't whether or not narcosis impairs you but rather how much (if any) impairment is acceptable. I think bad drivers are very often worse than drunk good ones but only one is illegal. LOL I would have to be pretty drunk to ba as bad as some of the drivers around here. Likewise you'd have to be pretty narced to be as bad as some of the divers that I see.

I would take the other view that adaptation does occur on frequent and progressively deeper dives. There has been actual reseach and experimentation on this and there are many experienced divers who function very well at depths of 150-170 ft on air. I do not agree that you cannot think at depth. About the only unavoidable loss that occurs is some degree of fine motor ability.

The debilitating effects of narcoisis is affected by other factors as well. A competent diver who has overlearned tasks (such as bouyancy control) to the point that they are automatic is at an advantage as his task loading is essentially reduced and he is better able to focus on the task at hand. Consequently he/she is less likely to be debilitated by narcosis at a given depth. Similarly, a diver with a better aptitude for focusing on tasks is also at an advantage and is again better able to focus on the task at hand.

There is also a critical psychological issue involved. A diver who has not been to conditioned to believe he is going to be severely narced at 170 ft, won't be, while a diver conditioned to think that narcosis is severe and debilitating at 100ft will be. In many cases divers are affected however they are expected and taught to be affected by narcosis. The well intentioned effort to teach divers that narcosis is extremely dangerous has unfortunately made those same divers more likely to be debilitated by narcosis at shallower depths than would happen otherwise.

As a psychologist, I would love to do further research in this area with regard to demand characteristics and the affects a diver's expectations has on their impairment at depth as well as measuring impairment on mental and physical ability at various actual depths versus perceived depths. (ie test a person at 50 ft who thinks he is at 150 ft and vice versa dn see what happens.)

World Champion once bubbled...
Hello,

Can you build a tolerance for nitrogen narcosis or is it a fixed phenomena?

Any thoughts are greatly appreciated,

Safe diving.

Click to expand...

As I understand you can build up a slight tolerance. If you dive deep (almost) every day then either the effect diminishes or your ability to cope increases with, in either case, the net effect of handling it better.

But the tolerance wears off in a few days too and you have to start from scratch again in building it up.

R..

I agree the effect fades over time. Generally two weeks without a deep dive is considered the outside limit before adaptation needs to be re developed.

Mike Ferrara is correct.

DA Aquamaster what studies are you referring to? The only studies I've heard of suggest that people become accustom to the effects of narcosis and only think they are preforming better. In reality they are not.

The Mount-Milner test in 1965 was a study of behavioral modeling effects on divers and their suceptibility to narcosis. It found that divers who expected to become narced did, some as shallow as 60ft. While those who were trained that it narcosis could be overcome performed well on mental and dexterity tasks to depths to 240 ft.

The study also showed that adaptation occurred during the course fo the study. Dr. Peter Bennett also found that frequency of exposure to deep diving does lead to adaptation in a 1990 study, although the physical mechanisim through which this occurrs is still unknown.

What is also very important about the Mount-Milner study is that through the use of three separate control groups it measured the effect that a diver's exectations to become impaired has on the degree to which they are actually impaired by narcosis. This effect has played a role in confouding many studies that have been completed since.

I have read one study in particular that found that all divers are impaired to some degree by narcosis at depths as shallow as 60 ft. However, this study was, in my opinion, confounded by participant bias in that the participants knew what was being studied and knew what the hypothesis was (ie, that all divers suffer some degree of impairment at 60 ft. In other studies it is less obvious and the effect is due only to the training the divers received before being selected to participate in the study. The fact of the matter is that most divers trained today are conditioned to believe that narcosis is a serious problem below 100-130 ft. and as you point out, that those who think they can perform well at depth are mistaken. These beliefs form what is in essence participant bias and affect the subjects perfomance on the tests at depth. Researchers seeking to prove the debilitating effects of narcosis at relatively shallow depths can also intorduce the potential for experimenter bias that can further confound the data recorded during the trials.

Consequently, I think it would be very interesting to perform mental and dexterity testing on experimental groups of divers who are 1)ignorant of their actual depth and 2) mislead as to being both shallower and 3) deeper than their actual depth in addition to replicating the behavioral modeling aspects of the Mount-Milner test on new student divers with no prior knowledge or expectations regarding narcosis.

Any volunteers