Hydration and Voice
The vocal folds are bathed in mucus, which acts as an important lubricant to protect them from the heat and friction of vibration. If the mucus remains thin and slippery, it will fulfill its lubricating role well. However, dehydration can contribute to increased viscosity of the mucus, making it thick and sticky, undermining its lubricating function. The importance and benefits of both internal and external hydration for vocal health have been well documented. Poor hydration increases phonatory effort and phonation threshold pressure (PTP, the minimum amount of subglottic pressure needed to initiate vocal fold vibration) (Leydon, Sivasankar, Falciglia, Atkins, & Fisher, 2009; Verdolini, Titze, & Fennell, 1994; Verdolini et al., 2002).
Recommendations for adequate fluid intake vary. In Dietary Reference Intakes: The Essential Guide to Nutrient Requirements, Otten, Hellwig, and Meyers (2006) recommend 3.7 liters per day of total beverages for adult males and 2.7 liters per day of total beverages for adult females.
Caffeine is a diuretic and thought to be dehydrating. The diuretic effect of caffeine occurs with consumption of about 250 mg. However, Maughan and Griffin (2003) report that regular caffeine consumers develop a tolerance to its effects, including the diuretic effect. Recent studies have examined effects of caffeine on voice in quantities ranging from about 100 to 400 mg (Erickson-Levandoski & Sivasankar, 2011; Franca, Simpson, & Schuette, 2013). These studies found that caffeine did not have a significant effect on vocal acoustics, PTP, or phonatory effort. However, caffeine can be a trigger for reflux, so people who have GERD should weigh this consideration in their caffeine consumption.
Alcohol is also a diuretic and can therefore be dehydrating. Interestingly, Hobson and Maughan (2010) concluded that the dehydrating effect of alcohol is blunted when the body is in a hypohydrated state (specifically for beer). This is not a convincing argument in favor of drinking alcohol for hydration, though, as the dehydrated state one would need to be in for the effect to occur is obviously vocally undesirable. For some, alcohol can be a reflux trigger. As with caffeine, moderation is key. Most health care providers recommend limiting oneself to no more than one to two drinks per day.
Many singers use lubricating throat sprays, such as Singer’s Saving Grace, Entertainer’s Secret, or Vocal-Eze. Roy, Tanner, Gray, Blomgren, and Fisher (2003) looked at the effect of three potential laryngeal lubricants (water, mannitol, and Entertainer’s Secret Throat Spray) on PTP, an indicator of efficient phonation and phonatory effort. They found that while mannitol did reduce PTP, the benefit lasted only 20 minutes. Water and Entertainer’s Secret had no significant effect on PTP.
Many singers believe that dairy products increase mucus production and can negatively impact the voice. However, there is no research that suggests an increase in laryngeal mucus viscosity associated with dairy products. On the contrary, there is some research that has found that dairy products do nothing to increase production or viscosity of mucus (Thiara & Goldman, 2012). Part of the reason for this myth may have to do with the fact that milk is a relatively viscous beverage. When you drink a glass of milk, you can see the residue clinging to the inside of the glass after it is empty. It will similarly coat the inside of the mouth and throat immediately after drinking, which may be perceived as a mucus-like sensation. Some people have a dietary intolerance for dairy products that may cause gastrointestinal symptoms and may wish to avoid such products for this reason.
Erickson-Levandoski, E., & Sivasankar, M. (2011). Investigating the effects of caffeine on phonation. Journal of Voice, 25(5), E215–E219.
Franca, M. C., Simpson, K. O., & Schuette, A. (2013). Effects of caffeine on vocal acoustic and aerodynamic measures of adult females. Codas, 25(3), 250–255.
Hobson, R. M., & Maughan, R. J. (2010). Hydration status and the diuretic action of a small dose of alcohol. Alcohol and Alcoholism, 45(4), 366–373.
Leydon, C., Sivasankar, M., Falciglia, D. L., Atkins, C., & Fisher, K. V. ( 2009). Vocal fold surface hydration: A review. Journal of Voice, 23(6), 658–665.
Maughan, R. J., & Griffin, J. (2003). Caffeine ingestion and fluid balance: A review. Journal of Human Nutrition and Dietetics, 16(6), 411–420.
Otten, J. J., Hellwig, J. P., & Meyers, L. D. (Eds.). (2006). Dietary reference intakes: The essential guide to nutrient requirements. Washington, DC: National Academies Press.
Roy, N., Tanner, K., Gray, S. D., Blomgren, M., & Fisher, K. V. (2003). An evaluation of the effects of three laryngeal lubricants on phonation threshold pressure (PTP). Journal of Voice, 17(3), 331–342.
Thiara, G., & Goldman, R. D. (2012). Milk consumption and mucus production in children with asthma. Canadian Family Physician, 58(2), 165–166.
Verdolini, K., Titze, I. R., & Fennell, A. (1994). Dependence of phonatory effort on hydration level. Journal of Speech, Language, and Hearing Research, 37(5), 1001–1007.
Verdolini, K., Min, Y., Titze, I. R., Lemke, J., Brown, K., van Mersbergen, M., . . . Fisher, K. (2002). Biological mechanisms underlying voice changes due to dehydration. Journal of Speech, Language, and Hearing Research, 45(2), 268–281.