Caffeine has multiple effects on the brain, which is why many of us keep reaching for our daily cup of coffee. It increases alertness, boosts energy, and makes us feel good. To understand how caffeine manipulates the brain in these ways, we must first identify the bodily chemicals that caffeine affects. They are adenosine, adrenaline, and dopamine.
1. Caffeine Increases Alertness by Blocking Adenosine
Adenosine is a neurotransmitter that makes us tired. It limits brain stimulation by blocking other neurotransmitters that excite the brain. During the day, our bodies create adenosine; when we sleep at night, adenosine levels decrease.
Caffeine’s molecular structure is similar to adenosine, which is a scientific way of saying that caffeine looks like adenosine. It binds with the same receptors that adenosine binds with, thereby blocking adenosine from reaching our brain. By preventing adenosine from reaching the brain, caffeine keeps us awake and alert.
If the brain doesn’t regularly get enough adenosine, however, it will create more receptors. When there are more receptors, more caffeine is needed to block them. This is why regular coffee drinkers build up a tolerance to caffeine and need more coffee for the same effect.
2. Caffeine Boosts Energy by Increasing Adrenaline Production
By blocking adenosine, caffeine lets those excitatory neurotransmitters that stimulate the brain move about freely. This leads to an increase neuron firing, and the pituitary gland notices the uptick in activity. The pituitary gland, in turn, releases hormones that activate the adrenal glands, which produce adrenaline.
The end result of this long chain of reactions is an increase in adrenaline levels. Adrenaline is the more common name for epinephrine — the same epinephrine that is used in epi-pens to stimulate people’s bodies when they go into shock. Also known as the “fight or flight” hormone, adrenaline boosts energy by:
- increasing blood pressure and elevating heart rate
- opening airways
- redirecting blood from some organs, like the stomach, to muscles
- causing the liver to release sugars
3. Caffeine Improves Mood by Delaying Dopamine Reabsorption
Dopamine is a neurotransmitter that makes us feel good. For instance, the body releases extra dopamine after exercising, which is why people sometimes experience a “runner’s high” shortly after finishing a workout. There’s always some dopamine in the brain, but elevated levels lead to improved moods.
Caffeine increases the amount of dopamine in our brain by blocking its reabsorption into our bodies. It doesn’t increase the amount of dopamine our bodies make, but it slows the rate at which dopamine leaves our brains and returns to our bodies. At the same time, it doesn’t impact how quickly the chemical goes from our bodies to our brains. This leads to elevated dopamine levels for a short time, which make us feel good.
This is also why caffeine is addictive. We become accustomed to the elevated dopamine levels and miss them when we don’t have caffeine to produce them.
You probably don’t think about how caffeine is impacting your neurotransmitters when you have your cup of coffee, but every effect that you enjoy is rooted in biochemistry. Thankfully, you don’t need a doctorate to tell that caffeine increases alertness, boosts energy, and makes us feel good. You just need to drink another cup of coffee!