How does caffeine impact your sleep? Research deep dive

How does caffeine impact your sleep? Research deep dive

HOW DOES CAFFEINE IMPACT YOUR SLEEP? RESEARCH DEEP DIVE

TLDR: CAFFEINE CONSISTENTLY REDUCES TOTAL SLEEP TIME, DELAYS SLEEP ONSET, AND WORSENS SLEEP QUALITY, WITH EFFECTS STRONGEST AT HIGHER DOSES AND WHEN CONSUMED CLOSER TO BEDTIME, THOUGH INDIVIDUAL SENSITIVITY AND HABITUAL USE CAN MODERATE THESE IMPACTS.

AN INTRODUCTION TO CAFFEINE AND SLEEP

Caffeine is the most widely consumed psychoactive substance globally, and its impact on sleep has been extensively studied across diverse populations and methodologies. The consensus from systematic reviews, meta-analyses, and experimental studies is that caffeine consumption—especially at higher doses and when ingested close to bedtime — significantly reduces total sleep time, increases sleep onset latency, decreases sleep efficiency, and impairs subjective sleep quality 1,2,13,16,48. Caffeine also alters sleep architecture, reducing deep (slow-wave) and REM sleep, and can delay the circadian phase, particularly when consumed in the evening 1,2,45. Individual differences, such as age, genetic variation (notably in the ADORA2A gene), habitual caffeine use, and sex, moderate these effects 2,19,31,47. While some studies in habitual users and specific populations (e.g., military, athletes, adolescents) report attenuated or variable effects, the overall evidence supports a robust negative impact of caffeine on sleep, with dose and timing being critical factors 7,11,41,28,49. Notably, caffeine’s alerting effects may lead to a cycle of increased daytime consumption to counteract sleep loss, further perpetuating sleep disturbances 5,25,33.

THE RESEARCH METHOD USED FOR THIS ARTICLE

A comprehensive search was conducted across over 170 million research paper, including databases such as Semantic Scholar and PubMed. In total, 1,037 papers were identified, 566 were screened, 411 were deemed eligible, and the top 50 most relevant and high-quality papers were included in this review. Our search strategy was as follows:

  • Identification: 1,037 papers identified related to our research question.

  • Screening: 566 papers were screened (removed papers with missing abstracts and duplicates).

  • Eligibility: 411 papers deemed eligible (removed papers with low relevance)

  • Selected: 50 papers selected (focused on the top 50 highest quality papers for this article).

OUR KEY FINDINGS BASED ON THE SCIENCE

Caffeine disrupts sleep by reducing duration, delaying onset, and limiting deep and REM stages. Meta-analyses and controlled trials consistently show that caffeine reduces total sleep time (by ~45 minutes), decreases sleep efficiency, increases sleep onset latency, and increases wake after sleep onset 1,2,13,16,48. Caffeine also increases light sleep (N1), reduces deep sleep (N3/N4), and impairs subjective sleep quality 1,2,11,41. These effects are dose-dependent and most pronounced when caffeine is consumed within 6–8 hours of bedtime 1,11,41,48.

Caffeine disrupts sleep by blocking adenosine, delaying your body’s sleep clock, and suppressing melatonin, especially when consumed later in the day. Caffeine acts primarily as an adenosine receptor antagonist, reducing sleep pressure and delaying the circadian phase, especially when consumed in the evening 3,14,18,45. It can also suppress melatonin secretion, further disrupting sleep timing 16,45. Chronic use may lead to some adaptation, but withdrawal can increase sleepiness and sleep propensity 17,34.

People vary in caffeine sensitivity based on age, genetics, and habits, which affects how much it disrupts their sleep. Older adults and those with certain genetic variants (e.g., in ADORA2A) are more sensitive to caffeine’s sleep-disrupting effects 2,19,31,47. Adolescents and children are also vulnerable, with higher caffeine intake linked to shorter sleep duration and poorer sleep quality 12,33,44,46,50. Habitual users may experience attenuated effects, but high chronic intake still shortens sleep 7,39.

Certain circumstances can amplify caffeine’s impact on sleep, leading to greater disruption and reduced recovery. Military personnel, athletes, and shift workers often use caffeine to counteract sleep deprivation, but this can impair recovery sleep and overall sleep quality 9,21,28,49. In adolescents, caffeine use is associated with delayed sleep timing and increased variability in sleep patterns 12,33,37,46. Some studies in unique environments (e.g., submarines) report mixed effects, possibly due to confounding factors 30.

THE ONGOING DISCUSSION

The research overwhelmingly supports that caffeine disrupts sleep, with the magnitude of effect depending on dose, timing, and individual susceptibility 1,2,11,41,48. The highest-quality evidence comes from meta-analyses and large experimental studies, which show robust, clinically meaningful reductions in sleep duration and quality, especially with high doses or late-day consumption 1,2,11,41,48. Mechanistically, caffeine’s antagonism of adenosine receptors and suppression of melatonin secretion explain its effects on both sleep homeostasis and circadian timing 3,14,16,18,45.

However, there is notable variability in individual responses, influenced by genetics (e.g., ADORA2A), age, sex, and habitual use 2,19,31,47. Some studies in habitual users or specific populations (e.g., military, athletes) report attenuated or mixed effects, suggesting possible adaptation or confounding by lifestyle factors 7,21,28,49. In children and adolescents, even moderate caffeine intake is associated with shorter sleep and poorer quality, raising public health concerns 12,33,44,46,50.

While some observational studies find weaker or null associations, these are often limited by self-report bias, confounding, or lack of objective sleep measures 6,24,30. The strongest evidence for causality comes from experimental and genetic studies 1,2,11,31,39,45. See below for a summary of key claims along with evidence, reasoning, and citations: 

  • Caffeine reduces total sleep time, efficiency, and increases sleep latency, especially at higher doses and when consumed close to bedtime: strong evidence for this claim supported by meta-analyses, RCTs, and consistent across populations 1,2,11,13,41,48

  • Caffeine disrupts sleep architecture, reducing deep and REM sleep: strong evidence for this claim supported by multiple electroencephalogram (EEG) and polysomnography (PSG) studies confirm changes in sleep stages 1,2,13,14,19,40

  • Evening caffeine delays circadian phase and suppresses melatonin: strong evidence for this claim supported by several experimental studies showing phase delays and reduced melatonin secretion 16,18,45

  • Individual sensitivity to caffeine’s sleep effects is influenced by genetics (ADORA2A), age, and habitual use: moderate evidence for this claim supported by genetic association and population studies showing variable responses 2,19,31,47

  • Habitual caffeine users may experience reduced sleep disruption, but high chronic intake still shortens sleep: moderate evidence for this claim supported by some observed adaptions, but high intake remains detrimental 7,17,39

  • In some observational studies, caffeine intake is not associated with sleep duration or quality: Weak evidence to support this claim as referenced cross-sectional and ecological studies show mixed or null results, likely due to confounding 6,24,30

LIMIT CAFFEINE AND MAKE SURE TO AVOID LATE INTAKE

Caffeine consistently impairs sleep duration, quality, and architecture, with the strongest effects at higher doses and when consumed later in the day. Individual differences in sensitivity exist, but the overall evidence supports limiting caffeine intake — especially in the afternoon and evening — to promote healthy sleep.

Despite robust evidence for caffeine’s negative impact on sleep, gaps remain regarding long-term adaptation, the role of genetic and sex differences, and the effects in under-studied populations (e.g., non-Western, older adults, children). More research is needed on interventions to mitigate caffeine’s sleep-disrupting effects and on the public health implications of widespread caffeine use. Future research should focus on clarifying the mechanisms of individual sensitivity, long-term adaptation to caffeine, and effective interventions to mitigate its sleep-disrupting effects.

In summary, the literature strongly supports that caffeine impairs sleep, with dose, timing, and individual factors shaping the magnitude of its effects, but important questions remain regarding long-term adaptation and personalized risk.

  • How do genetic and sex differences modulate individual sensitivity to caffeine's sleep-disrupting effects? Understanding these differences could enable personalized recommendations and identify at-risk populations for sleep disturbances.

  • What are the long-term effects of chronic caffeine consumption on sleep architecture and circadian rhythms? Most studies focus on acute or short-term effects; long-term impacts are less understood but highly relevant for public health.

  • Which interventions (behavioral or pharmacological) can effectively mitigate caffeine-induced sleep disruption? Identifying effective strategies could help individuals who rely on caffeine but wish to maintain healthy sleep patterns.

In summary, the literature strongly supports that caffeine impairs sleep, with dose, timing, and individual factors shaping the magnitude of its effects, but important questions remain regarding long-term adaptation and personalized risk.

SOURCES

  1. Gardiner, C., Weakley, J., Burke, L., Roach, G., Sargent, C., Maniar, N., Townshend, A., & Halson, S. (2023). The effect of caffeine on subsequent sleep: A systematic review and meta-analysis.. Sleep medicine reviews, 69, 101764 . https://doi.org/10.1016/j.smrv.2023.101764.

  2. Clark, I., & Landolt, H. (2017). Coffee, caffeine, and sleep: A systematic review of epidemiological studies and randomized controlled trials.. Sleep medicine reviews, 31, 70-78 . https://doi.org/10.1016/j.smrv.2016.01.006.

  3. Reichert, C., Deboer, T., & Landolt, H. (2022). Adenosine, caffeine, and sleep–wake regulation: state of the science and perspectives. Journal of Sleep Research, 31. https://doi.org/10.1111/jsr.13597.

  4. Thölke, P., Arcand-Lavigne, M., Lajnef, T., Frenette, S., Carrier, J., & Jerbi, K. (2025). Caffeine induces age-dependent increases in brain complexity and criticality during sleep. Communications Biology, 8. https://doi.org/10.1101/2024.05.27.596056.

  5. Roehrs, T., & Roth, T. (2008). Caffeine: sleep and daytime sleepiness.. Sleep medicine reviews, 12 2, 153-62 . https://doi.org/10.1016/J.SMRV.2007.07.004.

  6. Watson, E., Coates, A., Kohler, M., & Banks, S. (2016). Caffeine Consumption and Sleep Quality in Australian Adults. Nutrients, 8. https://doi.org/10.3390/nu8080479.

  7. Weibel, J., Lin, Y., Landolt, H., Kistler, J., Rehm, S., Rentsch, K., Slawik, H., Borgwardt, S., Cajochen, C., & Reichert, C. (2021). The impact of daily caffeine intake on nighttime sleep in young adult men. Scientific Reports, 11. https://doi.org/10.1038/s41598-021-84088-x.

  8. Weibel, J., Lin, Y., Landolt, H., Berthomier, C., Brandewinder, M., Kistler, J., Rehm, S., Rentsch, K., Meyer, M., Borgwardt, S., Cajochen, C., & Reichert, C. (2021). Regular Caffeine Intake Delays REM Sleep Promotion and Attenuates Sleep Quality in Healthy Men. Journal of Biological Rhythms, 36, 384 - 394. https://doi.org/10.1177/07487304211013995.

  9. Pauchon, B., Beauchamps, V., Gomez-Mérino, D., Erblang, M., Drogou, C., Beers, P., Guillard, M., Quiquempoix, M., Léger, D., Chennaoui, M., & Sauvet, F. (2024). Caffeine Intake Alters Recovery Sleep after Sleep Deprivation. Nutrients, 16. https://doi.org/10.3390/nu16203442.

  10. Van Der Linden, M., Olthof, M., & Wijnhoven, H. (2023). The Association between Caffeine Consumption from Coffee and Tea and Sleep Health in Male and Female Older Adults: A Cross-Sectional Study. Nutrients, 16. https://doi.org/10.3390/nu16010131.

  11. Gardiner, C., Weakley, J., Burke, L., Fernandez, F., Johnston, R., Leota, J., Russell, S., Munteanu, G., Townshend, A., & Halson, S. (2024). Dose and timing effects of caffeine on subsequent sleep: a randomized clinical crossover trial. Sleep, 48. https://doi.org/10.1093/sleep/zsae230.

  12. Reichert, C., Veitz, S., Bühler, M., Gruber, G., Deuring, G., Rehm, S., Rentsch, K., Garbazza, C., Meyer, M., Slawik, H., Lin, Y., & Weibel, J. (2020). Wide awake at bedtime? Effects of caffeine on sleep and circadian timing in male adolescents - a randomized crossover trial.. Biochemical pharmacology, 114283 . https://doi.org/10.1016/j.bcp.2020.114283.

  13. Karacan, I., Thornby, J., Anch, A., Booth, G., Williams, R., & Salis, P. (1976). Dose‐related sleep disturbances induced by coffee and caffeine. Clinical Pharmacology & Therapeutics, 20. https://doi.org/10.1002/cpt1976206682.

  14. Landolt, H., Rétey, J., Tönz, K., Gottselig, J., Khatami, R., Buckelmüller, I., & Achermann, P. (2004). Caffeine Attenuates Waking and Sleep Electroencephalographic Markers of Sleep Homeostasis in Humans. Neuropsychopharmacology, 29, 1933-1939. https://doi.org/10.1038/sj.npp.1300526.

  15. Das, N., Woolf, B., Page, S., Richmond, R., & Khouja, J. (2025). Exploring the Relationship between Caffeine Consumption, Caffeine Metabolism, and Sleep Behaviours: A Mendelian Randomisation Study. . https://doi.org/10.1101/2025.04.30.25326725.

  16. Shilo, L., Sabbah, H., Hadari, R., Kovatz, S., Weinberg, U., Dolev, S., Dagan, Y., & Shenkman, L. (2002). The effects of coffee consumption on sleep and melatonin secretion.. Sleep medicine, 3 3, 271-3 . https://doi.org/10.1016/S1389-9457(02)00015-1.

  17. Weibel, J., Lin, Y., Landolt, H., Garbazza, C., Kolodyazhniy, V., Kistler, J., Rehm, S., Rentsch, K., Borgwardt, S., Cajochen, C., & Reichert, C. (2019). Caffeine-dependent changes of sleep-wake regulation: Evidence for adaptation after repeated intake. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 99. https://doi.org/10.1101/641480.

  18. Landolt, H. (2015). Caffeine, the circadian clock, and sleep. Science, 349, 1289 - 1289. https://doi.org/10.1126/science.aad2958.

  19. Robillard, R., Bouchard, M., Cartier, A., Nicolau, L., & Carrier, J. (2015). Sleep is more sensitive to high doses of caffeine in the middle years of life. Journal of Psychopharmacology, 29, 688 - 697. https://doi.org/10.1177/0269881115575535.

  20. Schlichtiger, J., Brunner, S., Strüven, A., Hoppe, J., & Stremmel, C. (2025). Effects of Caffeine Intake on Self-Administered Sleeping Quality and Wearable Monitoring of Sleep in a Cohort of Young Healthy Adults. Nutrients, 17. https://doi.org/10.3390/nu17091503.

  21. Chaudhary, N., Taylor, B., Grandner, M., Troxel, W., & Chakravorty, S. (2021). The effects of caffeinated products on sleep and functioning in the military population: A focused review. Pharmacology Biochemistry and Behavior, 206. https://doi.org/10.1016/j.pbb.2021.173206.

  22. Březinová, V. (1974). Effect of caffeine on sleep: EEG study in late middle age people.. British journal of clinical pharmacology, 1 3, 203-8 . https://doi.org/10.1111/J.1365-2125.1974.TB00237.X.

  23. Wu, M., Ho, K., Crocker, A., Yue, Z., Koh, K., & Sehgal, A. (2009). The Effects of Caffeine on Sleep in Drosophila Require PKA Activity, But Not the Adenosine Receptor. The Journal of Neuroscience, 29, 11029 - 11037. https://doi.org/10.1523/JNEUROSCI.1653-09.2009.

  24. Hu, Y., Stephenson, K., & Klare, D. (2020). The dynamic relationship between daily caffeine intake and sleep duration in middle‐aged and older adults. Journal of Sleep Research, 29. https://doi.org/10.1111/jsr.12996.

  25. O'Callaghan, F., Muurlink, O., & Reid, N. (2018). Effects of caffeine on sleep quality and daytime functioning. Risk Management and Healthcare Policy, 11, 263 - 271. https://doi.org/10.2147/RMHP.S156404.

  26. Walsh, J., Muehlbach, M., Humm, T., Dickins, S., Sugerman, J., & Schweitzer, P. (2005). Effect of caffeine on physiological sleep tendency and ability to sustain wakefulness at night. Psychopharmacology, 101, 271-273. https://doi.org/10.1007/BF02244139.

  27. Schwierin, B., Borbély, A., & Tobler, I. (1996). Effects of N6-cyclopentyladenosine and caffeine on sleep regulation in the rat.. European journal of pharmacology, 300 3, 163-71 . https://doi.org/10.1016/0014-2999(96)00021-0.

  28. Bodur, M., Barkell, J., Li, X., & Hezaveh, Z. (2024). Does Caffeine Supplementation Affect Sleep in Athletes? A Systematic Review of Nine Randomized Controlled trials.. Clinical nutrition ESPEN. https://doi.org/10.1016/j.clnesp.2024.11.007.

  29. Teixeira, C., Bressan, J., Leal, A., Ribeiro, S., Juvanhol, L., Pimenta, A., & Hermsdorff, H. (2023). Higher caffeine consumption is associated with insufficient sleep time in Brazilian adults (CUME study). International Journal of Food Sciences and Nutrition, 74, 836 - 844. https://doi.org/10.1080/09637486.2023.2267793.

  30. Chabal, S., Folstein, J., Chinoy, E., Markwald, R., & Lieberman, H. (2023). Caffeine consumption and sleep in a submarine environment: An observational study. Journal of Sleep Research, 32. https://doi.org/10.1111/jsr.13901.

  31. Rétey, J., Adam, M., Khatami, R., Luhmann, U., Jung, H., Berger, W., & Landolt, H. (2007). A Genetic Variation in the Adenosine A2A Receptor Gene (ADORA2A) Contributes to Individual Sensitivity to Caffeine Effects on Sleep. Clinical Pharmacology & Therapeutics, 81. https://doi.org/10.1038/sj.clpt.6100102.

  32. Bonventre, S., Raymond, A., & Begdache, L. (2024). Caffeine Consumption, Sleep Quality and Anxiety Among College Students. Current Developments in Nutrition. https://doi.org/10.1016/j.cdnut.2024.103183.

  33. Mathew, G., Reichenberger, D., Master, L., Buxton, O., Chang, A., & Hale, L. (2021). Too Jittery to Sleep? Temporal Associations of Actigraphic Sleep and Caffeine in Adolescents. Nutrients, 14. https://doi.org/10.3390/nu14010031.

  34. Panagiotou, M., Meijer, M., Meijer, J., & Deboer, T. (2018). Effects of chronic caffeine consumption on sleep and the sleep electroencephalogram in mice. Journal of Psychopharmacology (Oxford, England), 33, 122 - 131. https://doi.org/10.1177/0269881118806300.

  35. Drapeau, C., Hamel-Hébert, I., Robillard, R., Selmaoui, B., Filipini, D., & Carrier, J. (2006). Challenging sleep in aging: the effects of 200 mg of caffeine during the evening in young and middle‐aged moderate caffeine consumers. Journal of Sleep Research, 15. https://doi.org/10.1111/j.1365-2869.2006.00518.x.

  36. Snel, J., & Lorist, M. (2011). Effects of caffeine on sleep and cognition.. Progress in brain research, 190, 105-17 . https://doi.org/10.1016/B978-0-444-53817-8.00006-2.

  37. Lunsford‐Avery, J., Kollins, S., Kansagra, S., Wang, K., & Engelhard, M. (2021). Impact of daily caffeine intake and timing on electroencephalogram-measured sleep in adolescents.. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine. https://doi.org/10.5664/jcsm.9736.

  38. Hwang, B., Lee, J., Lim, H., Huh, R., Ryu, M., Jee, S., & Kimm, H. (2025). Association between Caffeinated Beverages Consumption and Sleep Quality of Urban Workers. Korean Journal of Health Promotion. https://doi.org/10.15384/kjhp.2024.00101.

  39. Stucky, B., Henckel, L., Maathuis, M., Haba-Rubio, J., Marques-Vidal, P., Siclari, F., Heinzer, R., & Landolt, H. (2024). Community-based causal evidence that high habitual caffeine consumption alters distinct polysomnography-derived sleep variables. https://doi.org/10.1101/2024.12.11.24318776.

  40. Landolt, H., Dijk, D., Gaus, S., & Borbély, A. (1995). Caffeine Reduces Low-Frequency Delta Activity in the Human Sleep EEG. Neuropsychopharmacology, 12, 229-238. https://doi.org/10.1016/0893-133X(94)00079-F.

  41. Gardiner, C., Weakley, J., Johnston, R., Fernandez, F., Townshend, A., & Halson, S. (2023). O050 The Dose and Timing Relationship between Caffeine and Subsequent Sleep. Sleep Advances: A Journal of the Sleep Research Society, 4, A19 - A20. https://doi.org/10.1093/sleepadvances/zpad035.050.

  42. Chaudhary, N., Grandner, M., Jackson, N., & Chakravorty, S. (2016). Caffeine consumption, insomnia, and sleep duration: Results from a nationally representative sample.. Nutrition, 32 11-12, 1193-9 . https://doi.org/10.1016/j.nut.2016.04.005.

  43. Ramos-Campo, D., Pérez, A., Ávila-Gandía, V., Pérez-Piñero, S., & Rubio-Arias, J. (2019). Impact of Caffeine Intake on 800-m Running Performance and Sleep Quality in Trained Runners. Nutrients, 11. https://doi.org/10.3390/nu11092040.

  44. Jessel, C., Narang, A., Zuberi, R., & Bousman, C. (2023). Sleep Quality and Duration in Children That Consume Caffeine: Impact of Dose and Genetic Variation in ADORA2A and CYP1A. Genes, 14. https://doi.org/10.3390/genes14020289.

  45. Burke, T., Markwald, R., McHill, A., Chinoy, E., Snider, J., Bessman, S., Jung, C., O’Neill, J., & Wright, K. (2015). Effects of caffeine on the human circadian clock in vivo and in vitro. Science Translational Medicine, 7, 305ra146 - 305ra146. https://doi.org/10.1126/scitranslmed.aac5125.

  46. Halldorsson, T., Kristjansson, A., Thorisdottir, I., Oddsdóttir, C., Sveinbjörnsson, J., Benediktsson, R., Sigfusdottir, I., Jörundsdóttir, H., & H, G. (2021). Caffeine exposure from beverages and its association with self-reported sleep duration and quality in a large sample of Icelandic adolescents.. Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 112549 . https://doi.org/10.1016/j.fct.2021.112549.

  47. Erblang, M., Drogou, C., Gomez-Mérino, D., Metlaine, A., Boland, A., Deleuze, J., Thomas, C., Sauvet, F., & Chennaoui, M. (2019). The Impact of Genetic Variations in ADORA2A in the Association between Caffeine Consumption and Sleep. Genes, 10. https://doi.org/10.3390/genes10121021.

  48. Drake, C., Roehrs, T., Shambroom, J., & Roth, T. (2013). Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed.. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine, 9 11, 1195-200 . https://doi.org/10.5664/jcsm.3170.

  49. Hezaveh, S., Bodur, M., Barkell, J., & Li, X. (2024). P122 Various factors determine the impact of Caffeine on Athletes’ sleep. Sleep Advances: A Journal of the Sleep Research Society, 5, A70 - A71. https://doi.org/10.1093/sleepadvances/zpae070.204.

  50. Pollak, C., & Bright, D. (2003). Caffeine consumption and weekly sleep patterns in US seventh-, eighth-, and ninth-graders.. Pediatrics, 111 1, 42-6 . https://doi.org/10.1542/PEDS.111.1.42.