03.08.2023 **Tags** #areas/reading #areas/sleep #areas/biology #areas/fitness #areas/health # Caffeine Sleep pressure is caused by two things: the [[The Circadian Rhythm|circadian rhythm]] and a build up of adenosine. Adenosine builds up continuously after waking up and gets Caffeine intercepts adenosine by blocking the adenosine receptors, which leads to a feeling of alertness even if the adenosine concentration in the blood is high. The half-life of caffeine after consumption is between 5-7 hours. # References [[Why We Sleep - Unlocking the Power of Sleep and Dreams]]