Technical Divers Can Teach Us About Nitrogen Narcosis
While scientists remain divided on the issue, experienced technical divers are adamant that divers can stave off some of the effects of narcosis by continued and frequent deep diving. This is probably due to both physiological adaptation, and because the seasoned diver develops coping skills, such as concentrating more intently on the task at hand. The adaptation is only temporary, however, and decays over a matter of days or weeks once diving ceases. The coping skills may last longer. A high motivation to complete the task appears to help reduce symptoms, as well.
Applying these ideas, technical divers often use special techniques to prepare for a deep dive. The first is to acclimate to the planned depth through a series of "rehearsal dives." These are dives made over several days, in progressively deeper water, where divers engage in tasks similar to what they'll do on the final dive.
The second preparation technique used by technical divers is mental imagery. Before entering the water, the diver sits quietly with eyes closed and imagines, as vividly as possible, making the dive. This lets the diver anticipate what's likely to happen, and deal with any problems in a calm, considered and deliberate manner. Should any of these problems actually occur during the dive, he'll be better able to handle the situation as he has, in a sense, practiced overcoming the problem before the dive. In addition, the imaging technique may help avoid the common problem of "task fixation," in which concentrating so hard on overcoming one problem, the diver forgets about something else. An example might be fixating on adjusting a buckle, but forgetting to check your air supply. Mental imagery is also an aid to relaxation, and helps prevent starting your dive in an overly anxious mental state.
The effects of nitrogen narcosis are insidious. The early stages are virtually imperceptible; and by the time signs do become obvious to a buddy, the victim can be beyond the point of helping him or herself. Proper planning, preparation and awareness can prepare you to deal with the condition, and may even somewhat help you stave off the effects. But no matter what anyone tells you, everyone is affected. It's just a matter of when and where.