Habitual coffee consumption showed very low association with estimated patterns of sleep habits or perceived daytime sleepiness in a large cross-sectional cohort, suggesting coffee may be less impactful on sleep habits than previously thought.
Key Findings
Results
Habitual coffee consumption showed very low correlation with sleep quality and daytime sleepiness in a large Swedish cohort.
Cross-sectional study of 30,154 individuals participating in the Swedish Cardiopulmonary Bioimage Study (SCAPIS)
Different degrees of coffee consumption showed 'very low association with estimated patterns of sleep habits or perceived daytime sleepiness'
The study compared habitual coffee intake with sleep habits, subjective estimate of daytime sleepiness, and underlying genetic variants
Results held across a large, population-level sample allowing for broad generalizability
Methods
Self-reported coffee consumption was statistically confirmed through association with previously reported genetic variants related to coffee intake.
Genetic variants known to be associated with coffee consumption were used to validate self-reported habitual coffee intake
Statistical association with previously reported genetic variants confirmed different degrees of coffee consumption
This genetic validation strengthens the reliability of the coffee consumption measurement in the study
Discussion
Caffeine's well-characterized acute sleep-disrupting effects may be dampened in habitual adult coffee users through adaptive mechanisms of the adenosine system.
Caffeine exerts its psychoactive effects through interaction with adenosine receptors, which are involved in sleep regulation
While studies have shown a 'deleterious immediate effect of caffeine on sleep, less is known about the effects of chronic caffeine exposure'
Authors propose that 'adaptive capabilities of the adenosine system in adult coffee users may dampen its psychoactive potency' as a possible explanation
Alternatively, authors suggest coffee may simply 'be less impactful on sleep habits than previously thought'
Background
Coffee is identified as one of the most commonly consumed sources of caffeine globally, making caffeine one of the most widely used psychoactive substances.
Coffee is described as 'the most common drink in the world, second only to water'
This makes caffeine 'one of the most used psychoactive substances'
The large-scale population context motivates study of chronic rather than only acute caffeine effects on sleep
What This Means
This research suggests that people who regularly drink coffee do not appear to have meaningfully worse sleep or greater daytime sleepiness compared to those who drink less coffee. The study analyzed data from over 30,000 Swedish adults and used genetic markers associated with coffee drinking to confirm participants' reported intake, making the findings more reliable. Despite coffee being one of the world's most consumed beverages and caffeine being well-known for disrupting sleep in short-term experiments, the researchers found very little real-world connection between how much coffee people habitually drink and how well they sleep or how sleepy they feel during the day.
The findings point to a potentially important distinction between the immediate, acute effects of caffeine — which laboratory studies have consistently shown can interfere with sleep — and the long-term effects in people who drink coffee every day. The authors suggest that regular coffee drinkers may develop a kind of biological adaptation in their adenosine system (the brain pathway through which caffeine works), which could reduce caffeine's sleep-disrupting impact over time. This adaptation may explain why so many people report being able to drink coffee daily without feeling it harms their sleep.
This research matters because it challenges the common assumption that habitual coffee consumption is a major driver of poor sleep at the population level. However, it is a cross-sectional study, meaning it captures a snapshot in time rather than tracking individuals over time, which limits conclusions about cause and effect. The results suggest that for most regular adult coffee drinkers, habitual consumption may not be the primary factor behind sleep problems, though individual responses to caffeine can vary widely.