The Effect of Coffee on Sleep
How Does Drinking Coffee Affect Sleep?
Our basic life rhythm is primarily determined by two factors: the 24-hour circadian rhythm and the sleep drive.
Together, these regulate our daily cycle, especially the periods of sleep and wakefulness. Our circadian rhythm acts like an internal clock, providing a natural pace for our lives and helping our body stay in sync with the 24-hour cycle of the day.
However, there is another, lesser-known but equally important player in this dynamic: adenosine.
Adenosine is a compound that our body starts producing after waking, and its concentration gradually increases with every minute we stay awake. As the adenosine level rises, so does our drive to sleep. This sleep drive influences when we feel tired and when we need to rest.
When adenosine reaches a certain level, we experience an irresistible urge to sleep, typically after 12–16 hours of being awake. But what happens if we artificially suppress this sleep signal?
This is where coffee comes into play, one of the most widely used psychoactive stimulants worldwide that makes us feel more alert and refreshed. Many don’t realize that caffeine has a unique ability: it competes with adenosine by blocking its effects in the brain, thus delaying our sense of sleepiness.
Caffeine acts as a kind of barrier for adenosine, but it doesn’t stop adenosine from being produced—it just accumulates behind the wall raised by caffeine. This is a complex biochemical balancing act where caffeine temporarily overrides our natural need to sleep. However, once the caffeine is metabolized by our liver, the built-up adenosine is suddenly released, causing a strong sleep drive known as a "caffeine crash."
If you start your day immediately with coffee upon waking, you effectively block adenosine's effects right away, which means that by the afternoon, a lot more adenosine will have piled up in your system and will rush over you at once, intensifying that afternoon fatigue.
It’s best to wait at least 90 minutes after waking before having your first coffee. This gives time for the morning-produced adenosine to be absorbed, making your coffee feel more energizing in the hours after.
How Long Does Caffeine’s Effect Last?
Many people don’t realize that the caffeine in a single coffee can take 10 to 14 hours to completely clear from the body! This means that a coffee drunk at, say, 5 p.m. can still be active at 11 p.m., strongly impacting your sleep quality!
Caffeine isn’t limited to just coffee; it’s also found in tea, energy drinks, certain foods like ice creams, and medications—all of which affect our sleep patterns. Moreover, "decaffeinated" coffee isn’t truly caffeine-free. Most of these products contain 15–30% of the caffeine found in regular coffee, so consuming them in the evening can also disrupt sleep.
It’s also important to consider that caffeine metabolism can slow down with age, increasing its sleep-disrupting effects.
A quick side note: You probably know someone who can drink an espresso at 10 p.m. and still fall asleep easily an hour later. These people tend to have a liver enzyme (CYP1A2, a cytochrome P450 liver enzyme) that breaks down caffeine faster. Because of this, such individuals metabolize caffeine quicker than most of us and can enjoy late-evening coffee without consequences.
Understanding the relationship between coffee and sleep is key to developing healthy sleeping habits. The more we learn about the biology of sleep and caffeine’s effects, the better our ability to make conscious choices about how we influence our sleep patterns daily. Grasping the dynamics between adenosine and caffeine is a step toward managing our sleep and overall wellbeing more effectively.
Interesting Facts About Coffee
Goats Discovered Coffee
Legend has it that an Ethiopian shepherd named Kaldi noticed his goats becoming more energetic and lively after eating the red berries from a certain bush. That bush was the coffee plant.
The World’s Most Expensive Coffee: Kopi Luwak
This special coffee is made from coffee beans eaten and then excreted by a civet cat. The digestive enzymes impart a unique aroma to the beans—and its price can reach 360,000 HUF/kg.
Coffee Is the Second Most Traded Commodity in the World
Only oil surpasses it in global trade volume. Worldwide, 2.25 billion cups of coffee are consumed daily.
Coffee in the History of Bans
There have been several historical periods when coffee drinking was banned—such as in the Ottoman Empire and in 17th-century Europe—because it stimulated thinking and social gatherings.
The Scandinavian Countries Lead in Coffee Consumption
Most coffee is not consumed by Italians or Americans, but by populations like the Finnish, who consume on average 10–12 kg per person annually.
The Flavor of Coffee Isn’t Due to Caffeine
Caffeine is bitter, but the complex aroma of coffee comes from more than 800 volatile compounds—more than have ever been identified in wine or chocolate.
The World's Oldest Coffeehouse Is Still in Operation
The Caffè Florian in Venice has been operating since 1720 and is one of the world's oldest coffeehouses, visited by the likes of Goethe, Casanova, Lord Byron, and Charles Dickens.
The Smell of Coffee Also Has a Stimulating Effect
Studies show that even the aroma of coffee can improve alertness and cognitive performance, even if you don’t drink it.
CBD Oil with Coffee, or CBD Coffee
The combination of CBD Oil and coffee is becoming increasingly popular in the wellness world, but it's important to understand how these substances interact in our bodies. CBD has calming and anxiety-reducing properties, while caffeine is stimulating, raising the question: do they balance each other out or interfere with each other's effects?
How Do CBD and Caffeine Work Together?
Adenosine System: CBD increases adenosine levels in the brain, contributing to its relaxing and sleep-supporting effects. In contrast, caffeine blocks adenosine receptors, creating alertness. Consumed together, caffeine can inhibit CBD’s calming effects.
Anxiety and Nervousness: Excessive caffeine consumption can induce anxiety and nervousness. CBD, however, may help alleviate these symptoms, so the combination might provide a more balanced experience for some.
When Is It Best to Consume Them Separately?
If you primarily use CBD to improve sleep quality, it’s wise to avoid consuming it together with caffeine. Take your CBD Oil on an empty stomach in the morning, then wait at least 90 minutes before drinking coffee, so the CBD can exert its calming effect.
