Question: How does caffeine keep you awake

Petrina Lau answered on 13 Nov 2018:

Hi there! Caffeine is a type of drug that promotes alertness. it is a drug by a broad definition. Caffeine acts as an “adenosine receptor antagonist.” Adenosine is a substance in your body that promotes sleepiness. Caffeine blocks the adenosine receptor to keep you from feeling sleepy.

Caffeine begins to affect your body very quickly. It reaches a peak level in your blood within 30 to 60 minutes. It has a half-life of 3 to 5 hours. The half-life is the time it takes for your body to eliminate half of the drug. The remaining caffeine can stay in your body for a long time.