The Neuroscience of Caffeine and an Anxious Nervous System

Dana Frayne, Advanced Clinical Fellow

Have you ever noticed that it feels difficult to quiet your thoughts? Maybe your mind is racing and you feel like you’re fluttering from one thing to the next. This intense sense of go-go-go energy can result in an overwhelmed nervous system that is out of touch with the present moment.

Anxiety is so complex that one direct cause can't be identified. However, there is neuroscience research that explores caffeine’s role in an anxious nervous system. UCLA Health explains that when caffeine enters your brain, it binds to the neurotransmitter adenosine that typically helps your nervous system relax. However, when caffeine is present, the adenosine (the neurotransmitter that helps with relaxation) can no longer fulfill its function.

Furthermore, UCLA Health notes that caffeine actively stimulates your central nervous system. The central nervous system is the home of the “fight or flight” response, and when the central nervous system is activated with a stimulant, such as caffeine, the body is guided into a more activated state. Some physical symptoms of this can include an increased heart rate, sweaty palms, or chest tension. 

A study published in April 2026 explored the health impacts of caffeinated drinks, and one positive effect the researchers found was related to coffee diversifying the gut’s microbiome. While there was increased diversity in the gut microbiome found in this study, it is important to note the researchers also found that “Behaviourally, coffee drinkers exhibited greater impulsivity and emotional reactivity, whereas non-coffee drinkers demonstrated better memory performance.” Therefore, when considering whether a caffeinated drink feels like the right choice for you, it is important to tune into what feels aligned for your system. 

Ultimately, there is a complex picture that is continuing to emerge about caffeine and its impact on the nervous system. When we zero in on anxiety specifically, it’s important to consider how caffeine can send your nervous system into “fight or flight.” If you know that your nervous system is more sensitive to caffeine, it can be supportive to explore the impact of caffeine on your body’s regulating systems.