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Why can drinking too much coffee interfere with sleep?

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Paper bags filled with roasted coffee beans, ground coffee, and instant coffee granules arranged closely together. — coffee Roasted coffee beans, ground coffee, and instant coffee in paper bags.

Drinking too much coffee can interfere with sleep because of caffeine, a stimulant that interacts with the body's natural sleep-regulation process.1

The brain naturally produces a compound called adenosine as a byproduct of neuron activity. When adenosine levels rise, the body prepares for sleep. Caffeine functions by mimicking adenosine and binding to its receptors in the nervous system. By doing so, it effectively tricks the body into remaining alert and delays the onset of sleep.1

The effects of caffeine typically last for five to six hours, though individual sensitivity varies based on genetics and health. To avoid sleep disturbances, it is generally recommended to limit consumption to three or four cups per day and to avoid drinking coffee after the midafternoon. Excessive intake is also associated with other side effects, such as anxiety and jitteriness.12