How does caffeine affect the nervous system?

Caffeine primarily affects the nervous system by blocking the effects of adenosine, a neurotransmitter that promotes relaxation and sleepiness. Under normal circumstances, adenosine levels in the brain gradually increase throughout the day, leading to increased feelings of drowsiness and decreased alertness. By binding to adenosine receptors without activating them, caffeine effectively inhibits adenosine’s ability to exert its calming effects. This antagonistic action leads to heightened alertness and a temporary improvement in cognitive functions, as it reduces drowsiness and enhances the feeling of wakefulness.

The pharmacological impact of caffeine can be particularly significant, as it stimulates the central nervous system and leads to increased neurotransmitter release, such as dopamine and norepinephrine, contributing to improved mood and energy levels. This mechanism of action is the primary reason why caffeine is commonly consumed to enhance focus and prevent fatigue. While it has a variety of effects on neurochemistry, its pivotal role in blocking adenosine is central to understanding how caffeine increases alertness.