Coffee is a beverage consumed worldwide with properties that increase energy by increasing alertness and decreasing sleepiness. Other beverages containing caffeine such as teas are leveraged for the same effect, but how does caffeine work in the body at the cellular level?
The feeling of sleepiness is the effect of the build-up of a molecule in the nervous system called adenosine. Adenosine is a chemical agent that acts as a neuromodulator or chemical messenger that slows the metabolic function of other cells. The longer you are awake, the more adenosine you will have in your body. Andrew Huberman, Professor of Neurobiology at Stanford University reiterated this principle; after sleeping 8 to 10 “deep, restful hours, adenosine is going to be very low in the brain; however, when you’ve been awake for 10, 15, or more hours, adenosine is going to be much higher.”
Caffeine functions by antagonizing adenosine by blocking adenosine receptors. When adenosine cannot bind to its proper receptor, it can no longer make you sleepy. Another molecule that is increased in our body after drinking caffeine is dopamine, which makes us feel more energetic and wakeful. Dopamine makes you feel good and motivated; furthermore, dopamine can be converted into adrenaline, otherwise called epinephrine, which increases attention and wakefulness.
It is critical to note that wakefulness is induced by caffeine at different rates in each individual. Huberman states that caffeine sensitivity varies: “some people are so sensitive to caffeine that they feel jittery if they drink it even in small amounts, other people can drink large amounts of caffeine and not feel jittery at all.” Because the amount of caffeine needed for optimal wakefulness and energy shifts from person to person, each individual should figure out their own effective dosage and intensity of caffeine.
