caffeine + water

C2 is a specific experimental intervention arm used in a clinical trial conducted by Southern Illinois University Carbondale to investigate the effects of caffeine and hydration on vocal performance. The intervention consists of a 200 mg oral dose of caffeine, administered as a tablet, taken with 500 mL (0.5 liters) of water. The study aims to determine if systemic hydration can mitigate the potentially dehydrating or performance-degrading effects of caffeine on the vocal folds and voice quality in healthy adults. Caffeine acts primarily as a non-selective antagonist of adenosine receptors, which leads to central nervous system stimulation and potential peripheral effects on fluid balance and smooth muscle function.

Other names

200mg caffeine and 500mL water