Although past studies have sometimes been a bit uncertain, it is sensible to believe that alcohol consumption could increase your risk of experiencing harmful nitrogen bubbles within your tissues, and from there, decompression sickness. That’s because of a perfect storm of increased peripheral blood flow, potential dehydration, and nitrogen absorption.
Your blood viscosity, too, is likely to increase which makes your blood thicker, and furthermore increasing your chance of DCS.
In fact, studies have actually shown that even nitrogen narcosis can become more likely at shallower than 30m if you dive after you consume alcohol.
Nitrogen narcosis is something that we all learn about, and many experience. The key is to recognise when one is feeling the effects of nitrogen narcosis, so that you can signal to your buddy and safely ascend a few metres. Now factor in being under the influence of alcohol. Could you be certain that you would recognise that moment and act appropriately? I very much doubt it, and that could lead into a downward spiral.
Excess nitrogen bubbles can be deadly – which is why drinking and diving can be extremely hazardous, especially when you factor in the loss of inhibitions and increased risk of decompression sickness, too. Dive professionals everywhere will tell you that it’s a perfect storm.