Effects of caffeine on vocal acoustic and aerodynamic measures of adult females.

PURPOSE To explore the effect of caffeine on voice, as evidenced by acoustic and aerodynamic measures, based on the fact that caffeine is considered to be a systemic dehydrating agent. METHODS The participants in this investigation were 58 females ranging in age from 18 to 35 years, who self-reported normal vocal production. The participants abstained from caffeine ingestion for 24 hours and from ingesting foods and liquids for 12 hours prior to the test. They were randomly assigned to one of two groups, control and experimental, and were individually tested. After the preliminary phase, participants in the experimental group ingested a 100 mg caffeine tablet; participants in the control group ingested placebo, and followed the same protocol as the experimental group. All participants were retested 30 minutes after ingesting caffeine or placebo. RESULTS Differences were not identified in any of the acoustic or aerodynamic measures across both groups. CONCLUSION These results suggest that a conservative (100 mg) dosage of caffeine may not have an impact on vocal acoustics and aerodynamics.