How Awake Does Coffee Really Make You?

How Awake Does Coffee Really Make You?

Caffeine is considered the most consumed psychoactive substance in the world. The alkaloid maintains its unchallenged position in Austria in its most widely used form—adult Austrians drink about three cups of coffee every day on average. In this quantity, the popular hot beverage has many positive effects. Moderate coffee consumption is thought to reduce the risk of cardiovascular diseases and certain types of cancer.

However, most people reach for a steaming cup for an entirely different reason each day. The stimulating effect of caffeine on the central nervous system makes the drink an indispensable pick-me-up for many. But how significant is the awakening effect of coffee with regular consumption? Recent research paints a nuanced picture.

The stimulating effect of caffeine is undeniable and well-researched. When orally consumed, for example, in coffee, it is rapidly absorbed by the body, and the stimulating effect on the central nervous system begins after about 15 to 30 minutes. Caffeine keeps the neurotransmitter adenosine in check, which protects us from overexertion and signals fatigue. Simultaneously, there is an increased release of the neurotransmitter dopamine, which has an energizing effect.

However, the magnitude of the effect depends on various factors, not just the amount of caffeine. There are genetic differences in caffeine sensitivity, and other lifestyle habits also play a role, such as whether one smokes or not. Additionally, it is noteworthy that caffeine does not make individuals who are well-rested and alert even more awake or focused, according to Carolin Reichert from the Center for Chronobiology at the University Psychiatric Clinics Basel. The effect is unequivocal in the case of sleep deficits.

Withdrawal for Research

Nevertheless, habituation with caffeine is also a crucial factor. “If we want a stimulating effect from coffee, we must not consume it chronically,” says Reichert. “Coffee is only a stimulant when our receptors are sensitive to it, and this requires periods of abstinence.”

Studies, where coffee-loving participants had to abstain from caffeine for a while and were observed in a sleep lab, provide data on this. When they then resumed controlled amounts of coffee, the consequences became visible, says Reichert. “A group at the University of Zurich showed that just four days of abstinence are sufficient to induce reduced deep sleep with morning caffeine intake the following night.”

The impression that morning coffee has a pronounced effect is probably due to a different reason among habitual caffeine consumers, says the researcher. Daily coffee drinkers acclimate the brain to caffeine intake and undergo a mini-withdrawal during the night, causing fatigue. The first cup in the morning alleviates this withdrawal symptom, making one feel more awake.

Activating Expectation

However, the placebo effect, especially in habitual coffee drinkers, should not be underestimated. In a recent experiment, a team from the Portuguese University of Minho under the direction of Nuno Sousa examined the expectations of coffee lovers by giving study participants either coffee or the same amount of caffeine in tablet form. Their brain activity was also examined directly before and 30 minutes after intake using magnetic resonance imaging scans.

While changes in the prefrontal cortex indicating activation were observed in both groups after consumption, participants who had consumed coffee, not just swallowed caffeine capsules, showed additional effects. In them, connectivity increased in higher visual cortex areas and in the network for cognitive control—both parts of the brain crucial for working memory and goal-directed action.

Sousa and colleagues attribute this to expectations, as published in the journal Frontiers in Behavioral Neuroscience: “These effects were specific to coffee consumption and were triggered by factors such as the distinctive smell and taste of the drink or the psychological expectation associated with consuming this beverage.” This aligns with the result of an experiment a few years ago that found the aroma of coffee alone can have performance-enhancing effects.

For chronobiologist Reichert, however, coffee is much more than a stimulant. “In some studies, there are indications that regular caffeine consumption could protect against neurodegenerative diseases. In the psychiatric field, for example, with affective disorders, some studies suggest that regular consumption can be beneficial.” And then, amidst all the self-optimization, there is another good reason to indulge in a hot cup: pure enjoyment. But even that does not leave the brain’s reward center unaffected.