Your Brain on Coffee
By: Brian Hoeflinger, MD
March 16, 2025 | #38
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Disclaimer: Opinions are my own. Not medical advice.
Medical Trivia of the Week
Which organ is primarily responsible for metabolizing caffeine? (the correct answer is at the end of this email)
- A) Brain
- B) Kidneys
- C) Stomach
- D) Liver
Coffee, Caffeine, & Your Brain
What is it about coffee that leaves you dreaming about that first cup in the morning? Is it the tantalizing aroma, the bold taste, or the daily ritual? All of those are important factors, and none are wrong. However, science suggests that the primary reason lies in the effects of caffeine on the brain.
Caffeine is a major component of the average cup of coffee and has several strong positive, as well as some negative, effects on the brain. Let’s take a closer look.
The Positive Effects of Caffeine on the Brain
The primary benefits of caffeine include increased alertness, wakefulness, and focus, as well as an elevated mood.
- Blocking Adenosine Receptors
Caffeine binds to and blocks adenosine receptors. Adenosine is a substance in the brain responsible for feelings of sleepiness and tiredness. When adenosine binds to its receptors, it signals the brain to slow down, making you feel drowsy. Since caffeine has a similar structure to adenosine, it can bind to these receptors, effectively blocking its effects. This results in a feeling of alertness and focus, especially beneficial when you’re feeling tired or groggy in the morning.
- Stimulating Dopamine Release
Caffeine stimulates the release of dopamine, one of the brain’s “feel-good” hormones. Dopamine helps to elevate mood, increase focus and wakefulness, and enhance motivation throughout the day.
- Boosting Noradrenaline and Cortisol
Caffeine can also stimulate the release of noradrenaline and cortisol, further enhancing alertness and arousal.
The Potential Downsides of Caffeine
While coffee has many benefits, excessive consumption can lead to some negative effects.
- Overstimulation
Too much caffeine may cause overstimulation, making it difficult to focus or concentrate. Some people may even start to feel jittery or anxious.
- Increased Heart Rate and Blood Pressure
Caffeine can elevate blood pressure and heart rate, which may be problematic for individuals with hypertension or heart disease.
- Sleep Disruptions
Caffeine can cause sleep disturbances, including insomnia and poor sleep quality. To minimize sleep disruptions, it is generally recommended to avoid coffee in the late afternoon or evening. According to sleep expert Matthew Walker, it is best to have your last caffeine consumption 10 to 12 hours before your bedtime. A good rule of thumb is that the further your last sip of coffee is from your bedtime, the less likely it will affect your sleep.
How Much Caffeine Is Safe?
It is important to note that the effects of caffeine vary from person to person. The FDA recommends a moderate coffee intake of up to 400 mg of caffeine per day, which is roughly equivalent to two cups of coffee. This amount is generally considered safe for the average person. However, excessive consumption can lead to the negative effects mentioned above.
Additionally, what works for one person may not work for another. As with many things in life, you have to find what suits you best.
My Final Thoughts
There is much more we could discuss about coffee and its effects on the brain, but I wanted to provide a brief overview of some key and interesting information. Ultimately, everyone has their own relationship with coffee and caffeine. Some people don’t consume caffeine at all, while others get their caffeine from sources beyond coffee.
For me personally, I enjoy a nice cup of coffee in the morning, especially on my days off. I find the entire experience relaxing and pleasurable, perhaps even more important than the actual effects of caffeine itself.
☕ What’s your relationship with coffee? Do you drink it for the taste, the ritual, or the energy boost?
New Podcast Episode - How to Improve Your Mental Health Through Diet & Lifestyle Changes
Check out this week's new podcast episode with Dr. Drew Ramsey.
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Impactful Quote of the Week
"The most difficult thing is the decision to act.”
- Amelia Earhart
(quoted in Tiny Experiments by Anne-Laure Le Cunff)
Book I'm Currently Reading & Enjoying
Tiny Experiments by Anne-Laure Le Cunff. Anne-Laure also has a wonderful weekly newsletter called Ness Labs.
All my best,
Brian Hoeflinger
P.S. - if you enjoyed this newsletter, you may enjoy my book that details my life as neurosurgeon and the loss of my oldest son, Brian (see below a synopsis).
My Book
Life and Death . . . Two words with such opposite meaning and which inflict such contradictory emotions and yet are so closely intertwined in our lives. As parents, we bring meaning and life into this world through our children. Our lives become defined as a result. We learn the joy, hardship, and responsibility of shaping an innocent life. But a day will come when that life will be taken. For some, death will come too soon. This is the story of my son, Brian Nicholas Hoeflinger, who died unexpectedly at age 18.
https://doctorhoeflinger.com/products/the-night-he-died-the-harsh-reality-of-teenage-drinking
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Medical Trivia Answer:
The correct answer is D) Liver
