When the cover of the vocal folds is relatively dehydrated, the phonation threshold pressure becomes higher. Additionally, caffeine is a central nervous system stimulant. This effect on the CNS could sabotage therapeutic efforts that encourage relaxation. Finally, caffeine can aggravate reflux because it weakens the lower esophageal sphincter. It may impair fine motor coordination and reduce sensation.
Alcohol is also a diuretic and can contribute to dehydration of the laryngeal mucosa.
Long term exposure to the irritants could lead to cellular changes of the mucosa that could signal the development of cancer. Essentials of Exercise Physiology. Laryngopharyngeal manifestations of gastroesophageal reflux disease. Common diagnoses and treatments in professional singers. Singular Publishing Group, Inc. 6.