Coffee Jitters — What Are They?

A common side effect of caffeine is the coffee jitters; the anxious and nervous feeling many of us get after drinking one too many cups of coffee. It is also used to describe the rush of adrenaline followed by a crash in energy, making it hard to concentrate on any tasks at hand. But what causes these jitters? Let’s dive into the science behind it!

Caffeine is a naturally occurring chemical produced by coffee plants as a defense mechanism; when released into the soil, it kills surrounding plants that it would compete with for sunlight. When absorbed by the body it blocks adenosine, the chemical that causes drowsiness. This prevents signals of tiredness from being transmitted throughout the body, allowing you to feel awake and alert!

However, caffeine immediately sends adrenaline through your body, stimulating a “fight or flight mode” that causes increased blood pressure. As a vasoconstrictor, caffeine naturally narrows and constricts our blood vessels, causing our hearts to have to work harder to pump, making us feel more anxious and ‘jittery’. Consuming too much caffeine leads to a buildup of adrenaline with nowhere to go, further resulting in palpitations and jitters. 

Caffeine mimics the symptoms of stress (adrenaline, high blood pressure, sweatiness, and jitters), causing many people to feel anxious and over-stimulated. It doesn’t cause anxiety, but can make already prevalent symptoms worse! This is seen many times within students; drinking coffee when studying for a hard test tends to make their stress go up, causing them to lose focus.