Too shallow to get narced?

[L13]

There are many factors that may contribute to narcosis and many people experience it differently.

Narcosis affects divers like alcohol—you feel fine, but actually experience progressive impairment beginning with the first drink (or couple of atmospheres).

Drinkers function with narcosis better than non-drinkers because they are used to being impaired.

CO2 build up due to exertion will greatly affect narcosis. It’s easy to see why when looking at the degree of narcosis based on gas:

Gas	Relative narcotic potency
He	0.045
Ne	0.3
H2	0.6
N2	1.0
O2	1.7
Ar	2.3
Kr	7.1
CO2	20.0

Note how CO2 is much higher than other gases. A slight increase in CO2 can significantly add to narcosis (and He significantly reducing it).

Narcosis adds to your baseline level of anxiety. If you’re nervous, a new diver or not fully comfortable in the underwater environment, narcosis only compounds one’s anxiety. Despite the tables and physiology being the same, the psychological burden is a contributing factor. For instance, drysuit diving with heavy weights in dark, cold water with low vis is quite different that diving in warm clear water wearing little more than a t-shirt and bathing suit. Experienced divers are more comfortable than newer ones, so the anxiety baseline is less.

Similarly, seasickness medicines, fatigue, drinking alcohol or not getting enough sleep the night before are contributing factors.

Except actual real world data contradicts this table. It isn't based on a measured narcotic effect, but rather is calculated base on a hypothesis that has been shown to not always be accurate.

 

[joebob24]

I loved it immensely and I am going to pursue that further

I have a theory that everyone is a little narked no matter what depth they are diving to and that is why diving is so popular.

 

[wetb4igetinthewater]

I get narced while getting rained on kitting up!

 

[freeflowigb]

I just did the same dive yesterday, and followed the advice of people here to turn the reg knob all the way out, and set it to the “dive” mode (my reg has that additional dive/pre-dive switch) once underwater. I definitely had much less confusion and dream-like sensations, but most importantly - my breathing got so much slower I barely noticed the noise of my bubbles. Overall a perfectly safe dive despite the 4-feet swell that was beating us up on the surface - I did not get even a hint of anxiety. I used to have a tendency to hyperventilate (actually panting like after a good run) once on the surface - that must be my lungs trying to get rid of the CO2 buildup. This time I was cool as a cucumber, and even the rough seas did not bother me at all.

To sum it up, it looks like CO2 was definitely to blame at least partially in my original “narcosis” experience, but nitrogen is apparently also doing its job - this time I still got that feeling of dreaming and pleasant numbness in the limbs. I talked to my guide about this, but he was positive he never got narced at 80 feet, not even at 120, but agreed individual physiology counts.

Thanks to all those who took time to answer my questions!

 

[steinbil]

I talked to my guide about this, but he was positive he never got narced at 80 feet, not even at 120, but agreed individual physiology counts.

From what I've gathered, he is guaranteed to be narced at 120ft, even if he doesn't register the effect.

 

[freeflowigb]

From what I've gathered, he is guaranteed to be narced at 120ft, even if he doesn't register the effect.

Even with my limited knowledge on the topic, that does sound deep enough to get it to me.

 

[OTF]

On deep dives it's very helpful to splash, then take a nice long break at the surface to FULLY catch your breath and relax your heart rate before descending. Gearing up, getting in, and hitting cold water can be strenuous. If you descend immediately you will be bringing unnecessary CO2 with you, leading to increased narcosis and an elevated air consumption rate.

Committing to a pre-descent surface rest period can be difficult when there's a lot of excitement and peer pressure to bomb down the line immediately. But on the dives that I spend some time waiting on the surface by chance or on purpose I save a couple hundred PSI and feel markedly less narked compared to dives when I rush down the line immediately.

 

[The Chairman]

On deep dives it's very helpful to splash, then take a nice long break at the surface to FULLY catch your breath and relax your heart rate before descending.

I'd like to see you do that on the Speigle Grove when there's a 3+ knot current.

 

[happy-diver]

"Rest" on the surface, I'd rather nuzzle a porcupine with my face, stabilise at depth

 

[freeflowigb]

"Rest" on the surface, I'd rather nuzzle a porcupine with my face, stabilise at depth

To be fair, we get very calm waters here in Thailand, so his advice was on point for me. The only problem is the swell, but it hits rarely, and is almost negligent in bays.