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September 2017    Download the Entire Issue (PDF) Available to the Public Vol. 43, No. 9   RSS Feed for Undercurrent Issues
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Enraptured or Anxious? – You’re Narked

nitrogen narcosis lies in wait for the unwary

from the September, 2017 issue of Undercurrent   Subscribe Now

Jacques Cousteau called nitrogen narcosis "The Rapture of the Deep." He obviously enjoyed it!

Decades ago, certification manuals talked about Martini's Law, claiming that at every 30 feet, the effect was the equivalent of one martini, so at 90 feet, one was as schnockered as he would be after a three-martini lunch.

Well, that's just not true. Yes, there are many effects, but narcosis affects each diver differently and at different depths. Scientists aren't fully clear as to why, other than to say that the nitrogen you breathe under pressure affects your nervous system.

The deeper you go, the more likely you are to be affected, which means impaired performance (especially on unpracticed tasks), impaired reasoning, delayed responses, making calculation errors, fixating on an idea, memory loss, and even having a sense of well-being, over-confidence, and euphoria.

Go deeper, and things get worse. You'll suffer sleepiness, impaired judgment, confusion, and hallucinations, even terror.

While some diver training manuals indicate specific depths for the onset of narcosis while diving on air, the truth is, one person might start to suffer narcosis at only 30 feet (9m), while others can go to 130 feet (40m) breathing air and be unaffected. Everyone is different.

In the mid-'90s, I conducted a series of side-by-side regulator tests at 180 feet (55m) for Diver Magazine in the UK. I was careful to choose participating divers who were accustomed to going that deep, but some people criticized the tests and results, saying that the test divers would have been too 'narked' to make a critical judgment. However, I had taken the precaution of giving each a written general knowledge and mathematics test at that depth and found that the notes they made about the regulators at depth were not only legible but also corresponded with each other.

Still, narcosis kicks in for different divers at different depths. Samuel Johnson (Greensboro, NC) tells Undercurrent how he took a narcosis test during a dive to 95 feet (29m) during an advanced diver course. "When we got back to the surface, I found that the arithmetic [I did at depth] was wildly wrong, on the order of 2 + 2 = 73. However, I had had no sense of being 'narked' and no feeling of inebriation or any symptom. I thought I had done the ordinary arithmetic correctly!" He's now aware that he's susceptible to narcosis even at shallower depths.

Nitrogen Narcosis Can Kill You!

In 1990, Neal Watson and Bret Gilliam competed for the depth record depth achieved breathing ordinary air. Bret finally went deepest to 475 feet (146m). Bret said, "It was hard not to recall that all previous divers attempting to break the record had died trying." That's what narcosis can do.

Consider the story of Bob Raimo, who almost passed out on the way up at 325 feet (100m), diving on air in the Bahamas. His two buddies appeared to be totally unaffected. Who knows how deep they'd been? I wrote about the story in my first book, Amazing Diving Stories, in a chapter entitled "The Call of the Wah! Wah!"

Shortly after, TDI-co-founder Rob Palmer, attempting to emulate his peers, successfully made a series of air dives to 400 feet (120m) over a week in the Red Sea. He was last seen on his final big push, still going down.

Today, nitrox reduces nitrogen narcosis by substituting more oxygen for nitrogen. Technical divers go a step further with trimix, in which helium is substituted for some of the nitrogen. They have better clarity of vision and improved recall of the dive.

Euphoria or Fear and Anxiety?

We asked our readers if they have ever knowingly suffered nitrogen narcosis and done something stupid because of it. While many divers are often coy about reporting their mistakes, some were willing to share their experiences.

John Miller (Lubbock, TX), a master instructor, has seen how narcosis affects divers differently. He recalls a newly certified honeymoon couple suffering an incident at the Blue Hole in Belize when the man struck his head on a stalagmite going up while the woman, oblivious to her lack of buoyancy, sank back to 110 feet (34m) deep.

The Blue Hole is a place famous for depth and the narcosis that might come with it. Cindy Boling (Fort Worth, TX) dragged her partner Mark up from 165 feet (50m) despite his signaling he was "just fine." She had to do it more than once, a very risky profile.

Euphoria can cause you to go much deeper than you intended. This is what happened to Michele Berg (St. Louis, MO) soon after getting certified in Cabo. She ended up going well beyond the planned 100 feet (30m), then needed a considerable mandated deco stop, while her husband ran out of air and was rescued on a dive guide's octopus. A close call.

The wreck of the San Francisco Maru is one of Truk's best dives, but it's 180 feet (55m) to the bottom and can lead to the unwary getting 'narked'. James Burkhart (Katy, TX) wondered why his wife was above him, motioning him to come to her. He was hypnotized by the rapture of the deep, busy looking at the Japanese staff car and the magnetic mines filling the holds, and ended up having to make a long deco stop.

My own wife managed to get us mandated deco-stops of 45 minutes in the same way, on the same wreck, and that included switching to independent nitrox supplies for accelerated deco!

For some people, the effect is opposite of euphoria: fear. Mel McCombie (New Haven, CT) told us she used to suffer narcosis starting around 85 feet (26m), manifesting itself in fear and anxiety. She began a desensitizing program during which she gradually dived deeper and deeper at the same dive site over a period of days. She's done plenty of dives since and says her husband, Harris, never gets 'narked,'

And, confusion and muddy thinking can be a result. Bill Wohler (Menlo Park, CA) and his buddy dived to 136 feet (42m) at Monastery Beach in Monterey when both saw their computers were reading "1." Neither understood the reading, and it was only as they ascended and their heads cleared they realized they'd been 'narked'.

Diving in Penobscot Bay, Maine, at 100 feet (34m) deep, veteran diver Rich Wickenden (Plymouth, MA) says he was so confused that all the gauges on his console looked alike. He couldn't understand what they were telling him or what it all meant. Ascending to 80 feet (25m) solved the problem.

Great visibility can be seductive and cause you to go deeper than you intended. Diving in Roatan, Jean Fine (Sanford, FL) says she got narcosis at 150 feet (46m) breathing air on a planned deco dive and suddenly "couldn't think what the gauges were for let alone what they were indicating." She says it was utter confusion and now looks for any repeat effects on dives deeper than 90 feet (28m).

Are Inexperienced Divers More Vulnerable?

If you're an inexperienced diver, as you are when first certified, the effects of nitrogen narcosis can go unnoticed. Debra Cronenwett (Enfield, NH) relates how, during her first diving vacation in Jamaica many years ago, she went to 100 feet (30m) and felt her regulator was getting difficult to breathe through. She was tempted to discard it! Luckily, she grabbed her husband, who took her up to 80 feet (24m), where "the lights came back on."

Inexperienced divers may be more vulnerable, but it ain't necessarily so. Narcosis can give you tunnel vision, causing you to focus on one thing to the exclusion of all others. Ron Johns (Kearney, NE) remembers a divemaster who was prone to narcosis and spent 10 minutes video recording a lone shoe on the wreck of the Emperor in Lake Superior.

Narcosis can catch the very experienced, too. Dan Vale (Bowmanville, Ontario) was a commercial diver used to diving deep on air and found his tolerance to the 'narks' improved as he slowly worked down to greater depths. He thought he'd become acclimatized by regular exposure. That said, after he retired, he continued as a recreational diver and still once suffered temporary loss of peripheral vision on a fast descent during an air dive that bottomed out at 170 feet (52m) on a wreck in Lake Ontario.

It can also have a strange hallucinogenic effect. John Crossley (Panama Beach, FL) remembers seeing a large green moray with "a happy smile across his whole face with a full set of white dentures that would make any politician envious" during the ascent from a dive to 180 feet (55m) in Fiji.

Drawn by the seductive glint of something glittering silver while diving in Palau, Douglas Peterson (Naperville, IL) went to 136 feet (42m) to investigate. He was using nitrox for the first time. It was a beautiful fishing lure, but as he worked to cut its line free, he heard a strange sound. It was then he realized it was his computer sounding a depth alarm! Luckily, oxygen toxicity is governed by the twin factors of depth and time, and he was not there long enough to suffer any ill effects.

For some, it's not bad at all. Edward Noga (Akron, OH) thinks he's narked every time he dives a wreck at 100 feet (30m) or more in the Great Lakes. He says he always has clarity and control he's "as happy as a clam at high tide!"

So ...

The trick in dealing with narcosis is to recognize it and rise to a depth at which the symptoms dissipate and you feel comfortable. Keep in mind that euphoria is more difficult to detect. If your buddy is going deeper than you previously agreed, his judgment might be impaired. It's a difficult one to call, but get his attention and find out. Just because Jacques Cousteau seemed to enjoy the rapture of the deep, don't let your buddy or yourself become so enraptured that you risk your lives.


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