>The main physiological problem alcohol creates quickly for singers is dehydration. When the body is dehydrated, the mucous membranes -- including the mouth, throat, and vocal folds -- dry out easily. Dry vocal folds are more susceptible to irritation and injury; this may not be an immediate problem, but over years of drinking and singing, it may develop into nodules or hemorrhaging at the vocal folds, both of which are major problems.
>A secondary problem alcohol creates is that it can desensitize you to irritation while also decreasing your control over the vocal muscles. Desensitizing the throat area is dangerous because it robs you of the cues that tell you to rest your voice; together with impaired control over the laryngeal muscles, this can make you push your voice harder than you should. Add in the psychological effects -- disinhibition in particular -- and, again, you're more likely push too hard or try to sing outside your range. All of this is likely to cause an acute injury, and if it occurs over and over, can cause a more severe and lasting problem like vocal nodules.
