A Swedish study, published in PLOS ONE, investigated coffee consumption habits of ~30,000 middle-aged individuals and observed whether there was a correlation with sleep and sleepiness.
They found that individuals with higher coffee consumption reported sleep quality similar to low coffee consumers, with differences being minimal and potentially negligible. Factors such as BMI and stress may have higher impact on sleep according to the study. The researchers accounted for confounding factors including smoking, BMI, age, and sex. For example, men, smokers, and individuals with higher BMI report higher coffee consumption. Interestingly, in this middle aged group, over 80% of participants drink more than one cup a day.
There is a difference between acute and habitual coffee consumption. The nervous system adapts to habitual consumption, and the effects diminish over time. Effects persist only if consumption consistently increases, similar to other dependence patterns.
Many people experience discomfort when reducing coffee intake below their habitual level. Habitual coffee consumption mirrors regular dependence patterns. It could be better to use coffee as an “enhancer”, drinking occasionally rather than chronically, if we want to increase wakefulness, and perceived energy (not actual physiological energy).
One of the study’s limitations is that habitual coffee consumers may not perceive that they sleep poorly, even if objective measures could indicate a correlation. The study reports subjective factors self-reported by participants. Additionally, the researchers acknowledge the possibility of missing confounding factors that might have higher explanatory power for the outcomes.
In conclusion, regular coffee drinkers may not experience worse sleep if they maintain their current habits. However, they may not reap any possible “benefits” of coffee unless they shift to more occasional drinking, and may experience worsening if they reduce intake. If you choose to consume coffee occasionally, studies recommend drinking it before lunchtime to minimize sleep disruption (Gardiner et al., 2025).
Disclaimer: This article summarizes peer-reviewed research findings for educational purposes only and does not constitute medical advice. Individual tolerance to caffeine varies based on genetics, health conditions, and medication interactions. Consult a healthcare professional before making significant changes to your caffeine consumption habits.
Declaration of AI use: The author used Lumo AI for spelling, grammar-checking and proofreading during the preparation of this article.
References
Gardiner, C., et al. (2025). “Dose and timing effects of caffeine on subsequent sleep: a randomized clinical crossover trial.” Sleep, 48(4), zsae230. https://doi.org/10.1093/sleep/zsae230
Söderholm, S., et al. (2026). “Habitual coffee consumption poorly correlates with sleep quality and daytime sleepiness: A cross-sectional study.” PLOS ONE. https://doi.org/10.1371/journal.pone.0344479
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