Scuba diving has some inherent risks. But when alcohol is in your system, the sport’s risks may greatly increase.
Even just one drink can have a negative effect on your mental capacity and potentially set you up for physical harm. Some of the dangers of drinking and diving include increased risk of nitrogen narcosis, heat loss, and impaired judgment.
Divers who wish to drink can lower their risk of injury by limiting drinks to 2 or 3 the night before, going to bed early, hydrating before a dive, and avoiding alcohol at least an hour after diving.
Why Is Scuba Diving a Risky Sport?
Some health risks associated with scuba diving include thermal stress, barotrauma, the effects of breathing pressurized gases, and the potential for equipment failure.1
Nitrogen narcosis is one of the most common risks of diving. It’s a condition that can develop when people breathe compressed inert gasses such as nitrogen at deep sea depths. It can impact mental functioning and physical performance at depths as shallow as 10 meters.1,2
Effects can include changes in consciousness, behavior, and neuromuscular function. The symptoms tend to progress as the person dives deeper to greater pressures, but they are often reversible as the person comes back up to the surface.1,2
At increased depths, divers have been shown to exhibit symptoms such as:1
- Mental confusion.
- Delayed reaction time.
- Impaired judgment.
- Idea fixation.
- Memory loss.
The symptoms of nitrogen narcosis are also referred to as depth intoxication, “narks,” “rapture of the deep,” and the Martini effect.2
The likelihood that a diver will develop nitrogen narcosis depends on how deep they are diving, their physical and mental stamina, and how much experience they have with diving and managing underwater conditions. Other risk factors include anxiety, hypothermia, and fatigue.2
Decompression sickness is another hazard of diving. This condition, also known as Caisson disease or “the bends,” may develop after breathing compressed air while diving.3
Pressurized inert gas molecules, such as nitrogen, become more soluble in the blood relative to those breathed in the air at the surface. As a result, excess dissolved nitrogen accumulates in the blood and tissues during the descent potion of the dive. As divers begin to ascend, and pressures begin to normalize, this accumulated nitrogen can come back out of solution—forming bubbles in the blood and tissues, which may expand, injure tissues, or block blood vessels in other organs.3
Symptoms can include difficulty speaking, dizziness, and inflammation and swelling of joints.3
Drinking can exacerbate many of the risks associated with scuba diving and put people at risk for accidents and serious injury.
What Impact Does Alcohol Have on Scuba Diving Risks?
Many people on a scuba vacation will have a few drinks each evening. Some people even choose to drink alcohol before and after going scuba diving, or even between dives.
Drinking and diving entails a number of risks, including the following:
- Alcohol can increase the risk of nitrogen narcosis and can even intensify its effects.2,4
- The physiological consequences of drinking (e.g., increased peripheral blood flow and a relative increase in nitrogen absorption in the tissues, increased diuresis and the resulting risk of dehydration and increased blood viscosity, especially in small blood vessels) may increase the risk of nitrogen retention during a dive, resulting in an increased likelihood of bubble formation and decompression sickness as a diver ascends.5
- Alcohol can also lead to heat loss. It causes blood vessels in the skin to open up more than normal, and blood flow increases to fill the expanding vessels. This diverts blood from the body core and can contribute to hypothermia. Drinking after diving can also make it harder for the body to rewarm.5
- Alcohol can impair a part of the brain called the anterior cingulate cortex, which detects errors and self-corrects so you don’t make the error again. This deterioration can begin after just 1 or 2 drinks. Scuba diving involves multitasking, as you need to frequently check to make sure your equipment is working properly and monitor your available oxygen. Small mistakes in these areas can bring major risks to safety.6
- Alcohol also impacts other necessary diving skills, such as reaction time, visual tracking, attention span, and judgment. During a dive, you need to be able to navigate the currents, and you need your senses to be sharp so you can manage risks that may come up or handle emergencies such as an injury or damaged equipment.6
- In addition, alcohol can increase the possibility of vomiting, which can more easily lead to asphyxiation when diving.5
Finally, one very significant risk of drinking and diving is drowning. Drowning is one of the leading causes of unintentional death, especially among adult males. Alcohol has been implicated in 61% of non-boating-related drownings, and other studies have estimated that alcohol is involved in 25–50% of unintentional drowning deaths. Because alcohol can affect the central nervous system and a person’s cognitive processes, it may have a negative impact on a person’s ability to survive in the water, particularly if they become injured or confused.7
Tips for a Safe Dive
Here are some tips for managing alcohol use before and after a dive:5,6
- Avoid alcohol at least 8 hours prior to diving.
- Limit your drinks to 2 or 3 the night before and have a nonalcoholic drink in between them.
- If you’re scheduled to dive in the morning, turn in early the night before and close the bar tab off by 11:30 p.m. If you can’t get to sleep before midnight, skip the morning dive and go in the afternoon.
- Drink plenty of water or a sports drink the day of your dive to make sure you’re hydrated.
- Avoid alcohol for at least an hour after diving, and even longer if you were diving at depths greater than 80 feet.
How Do Diving Organizations Manage the Risks of Drinking and Diving?
Most responsible scuba diving organizations have a policy that prohibits diving after drinking. However, organizations vary in how they enforce this policy. Some are strict while others are more laissez-faire. Regardless, most organizations have divers sign a waiver to limit the organization’s liability in case of a mistake or accident—which means divers still have a responsibility to ensure their own safety.
Experienced divers know that scuba diving involves carefully handling risks while continuing to enjoy the sport. Having a successful dive requires a strategy that puts safety first, and this means being very careful about your use of alcohol.
. Clark, J. E. (2015). Moving in extreme environments: inert gas narcosis and underwater activities. Extreme Physiology & Medicine, 4(1).
. Kirkland, P. and Cooper, J.S. Diving, Nitrogen Narcosis. StatPearls.
. Bove, A. (2017). Decompression Sickness. Merck Manual.
. Lee, J. (2012). Drinking and Diving: Is It Safe? Alert Diver Online.
. Brylske, A. Alcohol, Nicotine & Divers – What You Should Know. Dive Training Magazine.
. Yeager, S. (2003). You Booze, You Lose. Scuba Diving.
. Pajunen et al. (2017). Unintentional drowning: Role of medicinal drugs and alcohol. BMC Public Health, 17, 388.