Multiple scientific studies and systematic reviews indicate that caffeine acts as an adenosine receptor antagonist that suppresses deep sleep, delays sleep timing, and negatively impacts overall sleep duration and quality.
The retrieved literature consistently supports the claim that caffeine consumption negatively impacts sleep duration and quality. Multiple studies (such as Shattuck & Matsangas 2017, and the systematic review on sleep EEG) demonstrate physiological and behavioral links between caffeine intake and sleep disruption, including reduced sleep duration, lighter sleep states, and delayed bedtimes.