Diving drunk

Recreational diving is a fun and entertaining activity - that's the goal. But there is a subtle margin between the pursuit of entertainment and hedonism. Without an essential sense of responsibility and a good knowledge of the risks, diving can easily succumb to a culture of unbridled pleasure seeking.

Diving, just like driving, requires a clear mind and the use of technical skills at all times. It is therefore unwise to dive under the influence of alcohol or other intoxicants, both for the diver and his partner. Let's review the post-festive reality of immersions made in the fruit of alcoholic fermentation or other intoxicants.

ALCOHOL

It is well known that alcohol alters many mental abilities. Alcohol consumption reduces reaction time, vision, concentration, ability to perform simultaneous tasks, judgment and psychomotor abilities [1].

If it seems unlikely that an experienced diver will become drunk, diving the day after a drunken evening may mean getting into the water with a significant blood alcohol level. The liver has a limited ability to metabolize alcohol, and this varies from one individual to another. Thus, even if the diver thinks he is perfectly sober and lucid, the reality may be different.

A study of recreational divers performing first level shallow dives showed significant performance alterations with blood alcohol levels above 0,04% [2]. These alterations were videotaped and confirmed by routine field sobriety tests performed "in the dry". These results are not unexpected, since cognitive disorders, especially in attention and concentration, can already be observed with a blood alcohol level of 0,02% [3]. What is more concerning, however, is the ignorance of the divers in the study as to the reduction in their performance and the increased risk of accidents they incur when diving under the influence of alcohol.

An analysis of more than 150 studies examining the effects of alcohol on cognitive performance identified a series of observations directly related to the diver [4].

Here are a few :

• Ingestion of alcohol, even in small amounts, impairs performance - the effects can be observed even after a single drink.
• Removing alcohol from the blood, at a rate of about 0,015% per hour, is not necessarily proportional to the improvement in cognitive performance.
• The increase in reaction time and the decrease in coordination follow a dose / response curve. Basically, the more alcohol you consume, the more these functions are altered.
• People who have consumed alcohol systematically underestimate the deleterious effects of the drink on their performance.
• Alcohol has a greater impact on tasks requiring the maintenance of multiple focus areas (such as diving) than on those involving a single focus of attention.

In addition to neurocognitive disorders, excess alcohol can cause a number of physiological alterations that may put the diver in danger. Acute alcohol poisoning can cause heart rhythm disturbances and a reduced ability of the heart to pump blood. These effects are sufficiently worrying in themselves not to add complications such as the performance of a physical effort or immersion in an underwater environment. Alcohol can also directly increase the risk of a diving accident. Indeed, dehydration, a common consequence of excess alcohol, is a known risk factor for decompression sickness (DCS). Alcohol also increases heat loss by dilating blood vessels, which can lead to hypothermia underwater.

Divers with alcohol effects are also more prone to nausea and vomiting during the dive, which, in addition to ruining diving, can lead to dehydration, impaired attention and increased risk of rapid ascent. uncontrolled, as many known risk factors for diving accidents.

Finally, like the other substances analyzed in this article, alcohol can make it more difficult to diagnose medical problems associated with diving. Underwater, the soporific effects of acute alcohol poisoning are indistinguishable from the signs of nitrogen narcosis. Also, back to the surface, the common manifestations of alcohol intoxication (including incoordination, drowsiness, nausea, and headache) may mimic or mask the signs of DC and delay its diagnosis and its treatment, or lead to unnecessary medical interventions.

CLASS A AND CLASS B DRUGS

According to research conducted by the Diving Diseases Research Center, 22% of divers admitted to having used one or more illicit drugs since starting their training. when diving, and 21% of these admitted to having taken a Class A drug, such as cocaine, or a Class B drug, such as cannabis (according to the UK classification) between five minutes and six hours before a dive. diving [5].

Cocaine is a stimulant that occurs within five minutes of its onset and lasts between one and two hours, although late effects can still be felt several days after a high dose. In short, the acute effects of cocaine can affect the diver in two ways. First, there are effects on the central nervous system, including mood exaltation, impaired judgment, and more risk-taking behavior. As we have seen above, these effects are dangerous in diving.

Secondly, because of the stimulation of the cardiovascular system, cocaine increases heart rate, blood pressure and abnormal heart rhythms. It has been shown that in case of increased physical exertion, these effects are a risk factor for sudden cardiac arrest.

Cannabis appears to be the favorite drug of divers [5]. The behavioral and physiological effects of cannabis appear within 10 minutes of taking it and, important data for divers, can last for three to five hours [5]. These effects can greatly increase the risk of a diving accident. Like alcohol, cannabis impairs perception and judgment, reduces inhibitions, and causes mood swings, all of which can be amplified by the effects of nitrogen narcosis. Cannabis also causes vasodilation of blood vessels, increases the risk of hypothermia and reduces motor coordination, limiting the technical skills of the diver. In addition, smoking cannabis or tobacco increases the level of carbon monoxide binding to hemoglobin in the blood, which reduces the body's ability to carry oxygen by 10% [6]. This can affect the diver's resistance to physical exertion and their ability to react in an emergency.

In addition to the acute effects of taking cannabis, prolonged consumption can cause other problems for the diver. As with smoking, chronic exposure to cannabis can cause respiratory problems, such as chronic bronchitis and sinusitis, which increase the risk of barotrauma with its potentially life-threatening consequences.

Keep in mind that the possession and consumption of Class A and B substances are punishable by law. Besides the obvious risk of criminal sanction, the diver should think about how their insurance company might react if they suspect that such substances played a role in a diving accident. It is very likely that reimbursement of the costs of hospitalization or hyperbaric treatment will be refused.

So while such advice may seem overdone or misplaced in an entertainment culture, divers are advised to stay away from drugs and avoid, or at least minimize, the use of alcohol during their diving trips. Without this, the risk of an accident becomes much more significant, not only for the diver, but also for his diving companions.