{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T16:45:15Z","timestamp":1790613915802,"version":"4.1.0"},"reference-count":108,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T00:00:00Z","timestamp":1776038400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100009687","name":"Wroc\u0142aw Medical University","doi-asserted-by":"publisher","award":["SUBZ.L010.26.045"],"award-info":[{"award-number":["SUBZ.L010.26.045"]}],"id":[{"id":"10.13039\/501100009687","id-type":"DOI","asserted-by":"publisher"}]},{"award":["SUBZ.L010.26.045"],"award-info":[{"award-number":["SUBZ.L010.26.045"]}],"id":[{"id":"https:\/\/ror.org\/01qpw1b93","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Introduction: Caffeine is the most widely consumed psychoactive stimulant worldwide and acts primarily through antagonism of adenosine A1 and A2A receptors, thereby reducing sleep pressure and promoting wakefulness. Although its alerting and performance-enhancing effects are well established, its influence on sleep-related electroencephalography (EEG) has been investigated across diverse paradigms with substantial methodological heterogeneity. This systematic and mechanistic review aimed to synthesize human evidence on how caffeine affects sleep architecture, quantitative sleep EEG, and neurophysiological markers of sleep homeostasis, and to interpret these findings within current models of adenosine-mediated sleep\u2013wake regulation. Materials and Methods: A systematic search of PubMed\/MEDLINE, Web of Science, Scopus, Embase, PsycINFO, ResearchGate, and Google Scholar was conducted for studies published between January 1980 and January 2026, with the final search performed on 10 January 2026. Eligible studies were original human investigations examining caffeine exposure or administration and reporting sleep-related EEG outcomes, including polysomnographic sleep staging, spectral EEG analyses, or other EEG-derived sleep metrics. Two reviewers independently screened records and assessed eligibility, with disagreements resolved by consensus. Data on study design, participant characteristics, caffeine interventions, EEG methodology, and outcomes were extracted using a predefined form. Risk of bias was evaluated using the RoB 2 and ROBINS-I tools. Owing to marked heterogeneity across studies, findings were synthesized narratively within a mechanistic interpretive framework. Results: Thirty-two studies were included. Across highly heterogeneous paradigms\u2014including acute bedtime or evening dosing, daytime or repeated caffeine use before nocturnal sleep, administration during prolonged wakefulness followed by recovery sleep, withdrawal protocols, and ambulatory\/home EEG monitoring\u2014the most consistent finding was suppression of low-frequency NREM EEG activity, particularly slow-wave activity and the lowest delta frequencies. Caffeine frequently increased faster EEG activity, including sigma\/spindle and beta ranges, producing a lighter, more aroused, and more wake-like sleep EEG profile. These effects were especially prominent during early-night NREM sleep and in recovery sleep after sleep deprivation, where caffeine attenuated the expected homeostatic rebound in low-frequency power. REM-related effects were less consistent, but some studies reported delayed REM timing and subtler alterations in REM EEG. Emerging evidence further suggests that caffeine increases EEG complexity and shifts sleep dynamics toward a more excitation-dominant state. Several studies indicated that quantitative EEG measures were more sensitive than conventional sleep-stage variables in detecting caffeine-related sleep disruption. Dose, timing, habitual caffeine use, withdrawal state, age, circadian context, and adenosinergic genetic variation, particularly involving ADORA2A, moderated the magnitude of effects. We also highlighted the connection between current results and sports and sports science. Conclusions: Caffeine reliably alters the neurophysiological architecture of human sleep in a direction consistent with reduced sleep depth and weakened homeostatic recovery. The overall evidence supports a mechanistic model centered on adenosine receptor antagonism, attenuation of sleep-pressure build-up and expression, and a shift toward greater cortical arousal during sleep. Sleep EEG appears to be a sensitive marker of these effects, often revealing physiological disruption even when conventional sleep architecture changes are modest. Future research should prioritize larger and more diverse samples, pharmacokinetic and pharmacogenetic characterization, and ecologically valid high-resolution sleep monitoring to clarify the real-world and functional consequences of caffeine-induced EEG changes.<\/jats:p>","DOI":"10.3390\/nu18081220","type":"journal-article","created":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T13:12:26Z","timestamp":1776085946000},"page":"1220","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["The Caffeinated Brain Part 2: The Effect of Caffeine on Sleep-Related Electroencephalography (EEG)\u2014A Systematic and Mechanistic Review"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-5320-3658","authenticated-orcid":false,"given":"James","family":"Chmiel","sequence":"first","affiliation":[{"name":"Faculty of Physical Culture and Health, Institute of Physical Culture Sciences, University of Szczecin, Al. Piast\u00f3w 40B blok 6, 71-065 Szczecin, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6996-8920","authenticated-orcid":false,"given":"Donata","family":"Kurpas","sequence":"additional","affiliation":[{"name":"Division of Research Methodology, Department of Nursing, Faculty of Nursing and Midwifery, Wroclaw Medical University, ul. Bartla 5, 51-618 Wroc\u0142aw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"e13597","DOI":"10.1111\/jsr.13597","article-title":"Adenosine, caffeine, and sleep-wake regulation: State of the science and perspectives","volume":"31","author":"Reichert","year":"2022","journal-title":"J. Sleep Res."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1007\/BF02245786","article-title":"Effects of caffeine on alertness","volume":"100","author":"Roehrs","year":"1990","journal-title":"Psychopharmacology"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"457","DOI":"10.2147\/NSS.S342922","article-title":"Effects of Caffeine Intake on Cognitive Performance Related to Total Sleep Deprivation and Time on Task: A Randomized Cross-Over Double-Blind Study","volume":"14","author":"Quiquempoix","year":"2022","journal-title":"Nat. Sci. Sleep"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"100051","DOI":"10.1016\/j.nbscr.2020.100051","article-title":"Multiple caffeine doses maintain vigilance, attention, complex motor sequence expression, and manual dexterity during 77 hours of total sleep deprivation","volume":"9","author":"Killgore","year":"2020","journal-title":"Neurobiol. Sleep Circadian Rhythm."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"479","DOI":"10.2147\/NSS.S401270","article-title":"Spotlight on Sleep Stage Classification Based on EEG","volume":"15","author":"Lambert","year":"2023","journal-title":"Nat. Sci. Sleep"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Pan, J., Wu, J., Liu, J., Wu, J., and Wang, F. (2021). A Systematic Review of Sleep in Patients with Disorders of Consciousness: From Diagnosis to Prognosis. Brain Sci., 11.","DOI":"10.3390\/brainsci11081072"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"277","DOI":"10.1016\/j.smrv.2007.05.001","article-title":"The use of evoked potentials in sleep research","volume":"11","author":"Colrain","year":"2007","journal-title":"Sleep Med. Rev."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Lustenberger, C., and Huber, R. (2012). High density electroencephalography in sleep research: Potential, problems, future perspective. Front. Neurol., 3.","DOI":"10.3389\/fneur.2012.00077"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1016\/j.neuron.2011.02.043","article-title":"Regional slow waves and spindles in human sleep","volume":"70","author":"Nir","year":"2011","journal-title":"Neuron"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1933","DOI":"10.1038\/sj.npp.1300526","article-title":"Caffeine Attenuates Waking and Sleep Electroencephalographic Markers of Sleep Homeostasis in Humans","volume":"29","author":"Landolt","year":"2004","journal-title":"Neuropsychopharmacology"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"685","DOI":"10.1038\/s42003-025-08090-z","article-title":"Caffeine induces age-dependent increases in brain complexity and criticality during sleep","volume":"8","author":"Lajnef","year":"2025","journal-title":"Commun. Biol."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Pauchon, B., Beauchamps, V., Gomez-M\u00e9rino, D., Erblang, M., Drogou, C., Beers, P.V., Guillard, M., Quiquempoix, M., L\u00e9ger, D., and Chennaoui, M. (2024). Caffeine Intake Alters Recovery Sleep after Sleep Deprivation. Nutrients, 16.","DOI":"10.3390\/nu16203442"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"e14140","DOI":"10.1111\/jsr.14140","article-title":"Concentration-effect relationships of plasma caffeine on EEG delta power and cardiac autonomic activity during human sleep","volume":"33","author":"Baur","year":"2024","journal-title":"J. Sleep Res."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1016\/0893-133X(94)00079-F","article-title":"Caffeine reduces low-frequency delta activity in the human sleep EEG","volume":"12","author":"Landolt","year":"1995","journal-title":"Neuropsychopharmacology"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1016\/0006-8993(95)00040-W","article-title":"Caffeine intake (200 mg) in the morning affects human sleep and EEG power spectra at night","volume":"675","author":"Landolt","year":"1995","journal-title":"Brain Res."},{"key":"ref_16","first-page":"108","article-title":"Caffeine effects on recovery sleep following 27 h total sleep deprivation","volume":"76","author":"LaJambe","year":"2005","journal-title":"Aviat. Space Environ. Med."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1016","DOI":"10.1016\/j.sleep.2009.01.001","article-title":"Effects of caffeine on daytime recovery sleep: A double challenge to the sleep-wake cycle in aging","volume":"10","author":"Carrier","year":"2009","journal-title":"Sleep Med."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"964","DOI":"10.1038\/sj.npp.1301198","article-title":"Effects of caffeine are more marked on daytime recovery sleep than on nocturnal sleep","volume":"32","author":"Carrier","year":"2007","journal-title":"Neuropsychopharmacology"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1111\/j.1365-2125.1974.tb00237.x","article-title":"Effect of caffeine on sleep: EEG study in late middle age people","volume":"1","year":"1974","journal-title":"Br. J. Clin. Pharmacol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"487","DOI":"10.1177\/0269881109104852","article-title":"Effects on sleep stages and microarchitecture of caffeine and its combination with zolpidem or trazodone in healthy volunteers","volume":"23","author":"Paterson","year":"2009","journal-title":"J. Psychopharmacol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"877","DOI":"10.5664\/jcsm.9736","article-title":"Impact of daily caffeine intake and timing on electroencephalogram-measured sleep in adolescents","volume":"18","author":"Kollins","year":"2022","journal-title":"J. Clin. Sleep Med."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1111\/j.1365-2869.2006.00518.x","article-title":"Challenging sleep in aging: The effects of 200 mg of caffeine during the evening in young and middle-aged moderate caffeine consumers","volume":"15","author":"Drapeau","year":"2006","journal-title":"J. Sleep Res."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"688","DOI":"10.1177\/0269881115575535","article-title":"Sleep is more sensitive to high doses of caffeine in the middle years of life","volume":"29","author":"Robillard","year":"2015","journal-title":"J. Psychopharmacol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1159\/000082851","article-title":"Recovery after prolonged sleep deprivation: Residual effects of slow-release caffeine on recovery sleep, sleepiness and cognitive functions","volume":"51","author":"Beaumont","year":"2005","journal-title":"Neuropsychobiology"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"114283","DOI":"10.1016\/j.bcp.2020.114283","article-title":"Wide awake at bedtime? Effects of caffeine on sleep and circadian timing in male adolescents\u2014A randomized crossover trial","volume":"191","author":"Reichert","year":"2021","journal-title":"Biochem. Pharmacol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"682","DOI":"10.1002\/cpt1976206682","article-title":"Dose-related sleep disturbances induced by coffee and caffeine","volume":"20","author":"Karacan","year":"1976","journal-title":"Clin. Pharmacol. Ther."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"109851","DOI":"10.1016\/j.pnpbp.2019.109851","article-title":"Caffeine-dependent changes of sleep-wake regulation: Evidence for adaptation after repeated intake","volume":"99","author":"Weibel","year":"2020","journal-title":"Prog. Neuropsychopharmacol. Biol. Psychiatry"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"777","DOI":"10.1016\/0031-9384(95)02093-4","article-title":"Metabolic rate and the restorative function of sleep","volume":"59","author":"Bonnet","year":"1996","journal-title":"Physiol. Behav."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"813","DOI":"10.1093\/sleep\/24.7.813","article-title":"Caffeine eliminates psychomotor vigilance deficits from sleep inertia","volume":"24","author":"Dongen","year":"2001","journal-title":"Sleep"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"692","DOI":"10.1038\/sj.clpt.6100102","article-title":"A genetic variation in the adenosine A2A receptor gene (ADORA2A) contributes to individual sensitivity to caffeine effects on sleep","volume":"81","author":"Adam","year":"2007","journal-title":"Clin. Pharmacol. Ther."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"196","DOI":"10.5664\/jcsm.28109","article-title":"Clinical and physiological correlates of caffeine and caffeine metabolites in primary insomnia","volume":"7","author":"Youngberg","year":"2011","journal-title":"J. Clin. Sleep Med."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1009","DOI":"10.1080\/00140139408963714","article-title":"The use of prophylactic naps and caffeine to maintain performance during a continuous operation","volume":"37","author":"Bonnet","year":"1994","journal-title":"Ergonomics"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"4668","DOI":"10.1038\/s41598-021-84088-x","article-title":"The impact of daily caffeine intake on nighttime sleep in young adult men","volume":"11","author":"Weibel","year":"2021","journal-title":"Sci. Rep."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1904","DOI":"10.1111\/j.1476-5381.2011.01689.x","article-title":"Polymorphisms of ADORA2A modulate psychomotor vigilance and the effects of caffeine on neurobehavioural performance and sleep EEG after sleep deprivation","volume":"165","author":"Bodenmann","year":"2012","journal-title":"Br. J. Pharmacol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"384","DOI":"10.1177\/07487304211013995","article-title":"Regular Caffeine Intake Delays REM Sleep Promotion and Attenuates Sleep Quality in Healthy Men","volume":"36","author":"Weibel","year":"2021","journal-title":"J. Biol. Rhythm."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"10472","DOI":"10.1523\/JNEUROSCI.1538-06.2006","article-title":"Adenosinergic mechanisms contribute to individual differences in sleep deprivation-induced changes in neurobehavioral function and brain rhythmic activity","volume":"26","author":"Adam","year":"2006","journal-title":"J. Neurosci."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1195","DOI":"10.5664\/jcsm.3170","article-title":"Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed","volume":"9","author":"Drake","year":"2013","journal-title":"J. Clin. Sleep Med."},{"key":"ref_38","first-page":"526","article-title":"Caffeine use as a model of acute and chronic insomnia","volume":"15","author":"Bonnet","year":"1992","journal-title":"Sleep"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"567","DOI":"10.1016\/j.sleep.2006.03.019","article-title":"Stress-related sleep disturbance and polysomnographic response to caffeine","volume":"7","author":"Drake","year":"2006","journal-title":"Sleep Med."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"zsae230","DOI":"10.1093\/sleep\/zsae230","article-title":"Dose and timing effects of caffeine on subsequent sleep: A randomized clinical crossover trial","volume":"48","author":"Gardiner","year":"2025","journal-title":"Sleep"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1002\/(SICI)1099-1077(199605)11:3<185::AID-HUP786>3.0.CO;2-M","article-title":"Caffeine-induced sleep disruption: Effects on waking the following day and its reversal with an hypnotic","volume":"11","author":"Alford","year":"1996","journal-title":"Hum. Psychopharmacol. Clin. Exp."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1265","DOI":"10.1126\/science.276.5316.1265","article-title":"Adenosine: A mediator of the sleep-inducing effects of prolonged wakefulness","volume":"276","author":"Strecker","year":"1997","journal-title":"Science"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1007\/BF01061844","article-title":"Comparative pharmacokinetics of caffeine in young and elderly men","volume":"11","author":"Blanchard","year":"1983","journal-title":"J. Pharmacokinet. Biopharm."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"1598","DOI":"10.1038\/s41593-019-0467-3","article-title":"Mechanisms of systems memory consolidation during sleep","volume":"22","author":"Klinzing","year":"2019","journal-title":"Nat. Neurosci."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1016\/j.smrv.2005.05.002","article-title":"Sleep function and synaptic homeostasis","volume":"10","author":"Tononi","year":"2006","journal-title":"Sleep Med. Rev."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/S0031-6997(24)01396-6","article-title":"Actions of caffeine in the brain with special reference to factors that contribute to its widespread use","volume":"51","author":"Fredholm","year":"1999","journal-title":"Pharmacol. Rev."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"1723","DOI":"10.2967\/jnumed.112.105114","article-title":"Caffeine occupancy of human cerebral A1 adenosine receptors: In vivo quantification with 18F-CPFPX and PET","volume":"53","author":"Elmenhorst","year":"2012","journal-title":"J. Nucl. Med."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"853","DOI":"10.1002\/mds.28897","article-title":"Adenosine A2A Receptor Occupancy by Caffeine After Coffee Intake in Parkinson\u2019s Disease","volume":"37","author":"Ishibashi","year":"2022","journal-title":"Mov. Disord."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"409","DOI":"10.1097\/00007691-200008000-00008","article-title":"Evaluation of caffeine as an in vivo probe for CYP1A2 using measurements in plasma, saliva, and urine","volume":"22","author":"Carrillo","year":"2000","journal-title":"Ther. Drug Monit."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Lin, Y.S., Weibel, J., Landolt, H.P., Santini, F., Garbazza, C., Kistler, J., Rehm, S., Rentsch, K., Borgwardt, S., and Cajochen, C. (2022). Time to Recover From Daily Caffeine Intake. Front. Nutr., 8.","DOI":"10.3389\/fnut.2021.787225"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"105194","DOI":"10.1016\/j.yrtph.2022.105194","article-title":"A double-blind, randomized, two-part, two-period crossover study to evaluate the pharmacokinetics of caffeine versus d9-caffeine in healthy subjects","volume":"133","author":"Sherman","year":"2022","journal-title":"Regul. Toxicol. Pharmacol."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1007\/978-3-642-13443-2_3","article-title":"Pharmacokinetics and metabolism of natural methylxanthines in animal and man","volume":"200","author":"Arnaud","year":"2011","journal-title":"Handb. Exp. Pharmacol."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1016\/0014-2999(82)90359-4","article-title":"Xanthine derivatives as adenosine receptor antagonists","volume":"81","author":"Fredholm","year":"1982","journal-title":"Eur. J. Pharmacol."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"262","DOI":"10.1007\/BF00171056","article-title":"Adenosine A2A receptors mediate the inhibitory effect of adenosine on formyl-Met-Leu-Phe-stimulated respiratory burst in neutrophil leucocytes","volume":"354","author":"Fredholm","year":"1996","journal-title":"Naunyn-Schmiedeberg\u2019s Arch. Pharmacol."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"684","DOI":"10.1016\/0009-9236(95)90025-X","article-title":"Sympathomimetic effects of paraxanthine and caffeine in humans","volume":"58","author":"Benowitz","year":"1995","journal-title":"Clin. Pharmacol. Ther."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"930","DOI":"10.1093\/sleep\/33.7.930","article-title":"Effects of paraxanthine and caffeine on sleep, locomotor activity, and body temperature in orexin\/ataxin-3 transgenic narcoleptic mice","volume":"33","author":"Okuro","year":"2010","journal-title":"Sleep"},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"637","DOI":"10.1016\/S0022-3565(25)09521-7","article-title":"Caffeine enhances acetylcholine release in the hippocampus in vivo by a selective interaction with adenosine A1 receptors","volume":"273","author":"Carter","year":"1995","journal-title":"J. Pharmacol. Exp. Ther."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"6321","DOI":"10.1523\/JNEUROSCI.22-15-06321.2002","article-title":"Caffeine induces dopamine and glutamate release in the shell of the nucleus accumbens","volume":"22","author":"Solinas","year":"2002","journal-title":"J. Neurosci."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"e549","DOI":"10.1038\/tp.2015.46","article-title":"Caffeine increases striatal dopamine D2\/D3 receptor availability in the human brain","volume":"5","author":"Volkow","year":"2015","journal-title":"Transl. Psychiatry"},{"key":"ref_60","doi-asserted-by":"crossref","unstructured":"Pic\u00f3-P\u00e9rez, M., Magalh\u00e3es, R., Esteves, M., Vieira, R., Castanho, T.C., Amorim, L., Sousa, M., Coelho, A., Moreira, P.S., and Cunha, R.A. (2023). Coffee consumption decreases the connectivity of the posterior Default Mode Network (DMN) at rest. Front. Behav. Neurosci., 17.","DOI":"10.3389\/fnbeh.2023.1176382"},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"2352","DOI":"10.1111\/j.1460-9568.2004.03310.x","article-title":"Expectation of caffeine induces dopaminergic responses in humans","volume":"19","author":"Kaasinen","year":"2004","journal-title":"Eur. J. Neurosci."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"101764","DOI":"10.1016\/j.smrv.2023.101764","article-title":"The effect of caffeine on subsequent sleep: A systematic review and meta-analysis","volume":"69","author":"Gardiner","year":"2023","journal-title":"Sleep Med. Rev."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"573","DOI":"10.1007\/s00213-009-1489-4","article-title":"Caffeine withdrawal, acute effects, tolerance, and absence of net beneficial effects of chronic administration: Cerebral blood flow velocity, quantitative EEG, and subjective effects","volume":"204","author":"Sigmon","year":"2009","journal-title":"Psychopharmacology"},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"3102","DOI":"10.1002\/hbm.20732","article-title":"The effect of daily caffeine use on cerebral blood flow: How much caffeine can we tolerate?","volume":"30","author":"Addicott","year":"2009","journal-title":"Hum. Brain Mapp."},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"305ra146","DOI":"10.1126\/scitranslmed.aac5125","article-title":"Effects of caffeine on the human circadian clock in vivo and in vitro","volume":"7","author":"Burke","year":"2015","journal-title":"Sci. Transl. Med."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"e12695","DOI":"10.1111\/jsr.12695","article-title":"Investigating genetic correlations and causal effects between caffeine consumption and sleep behaviours","volume":"27","author":"Treur","year":"2018","journal-title":"J. Sleep Res."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"4652","DOI":"10.1038\/s41467-022-32326-9","article-title":"Rhythmic transcription of Bmal1 stabilizes the circadian timekeeping system in mammals","volume":"13","author":"Abe","year":"2022","journal-title":"Nat. Commun."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"1564","DOI":"10.1126\/science.280.5369.1564","article-title":"Role of the CLOCK protein in the mammalian circadian mechanism","volume":"280","author":"Gekakis","year":"1998","journal-title":"Science"},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/B978-0-444-53839-0.00007-7","article-title":"Slow oscillations orchestrating fast oscillations and memory consolidation","volume":"193","author":"Born","year":"2011","journal-title":"Prog. Brain Res."},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"1411","DOI":"10.5665\/SLEEP.1290","article-title":"Fast and slow spindles during the sleep slow oscillation: Disparate coalescence and engagement in memory processing","volume":"34","author":"Bergmann","year":"2011","journal-title":"Sleep"},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1177\/155005940503600106","article-title":"Approximate entropy in the electroencephalogram during wake and sleep","volume":"36","author":"Burioka","year":"2005","journal-title":"Clin. EEG Neurosci."},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"zsaa226","DOI":"10.1093\/sleep\/zsaa226","article-title":"Changes in EEG permutation entropy in the evening and in the transition from wake to sleep","volume":"44","author":"Hou","year":"2021","journal-title":"Sleep"},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1016\/j.brainresbull.2003.09.004","article-title":"Sleep and synaptic homeostasis: A hypothesis","volume":"62","author":"Tononi","year":"2003","journal-title":"Brain Res. Bull."},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"2742","DOI":"10.1152\/jn.00575.2014","article-title":"Lempel-Ziv complexity of cortical activity during sleep and waking in rats","volume":"113","author":"Simons","year":"2015","journal-title":"J. Neurophysiol."},{"key":"ref_75","doi-asserted-by":"crossref","unstructured":"Aamodt, A., Sevenius Nilsen, A., Markhus, R., Kusztor, A., HasanzadehMoghadam, F., Kauppi, N., Th\u00fcrer, B., Storm, J.F., and Juel, B.E. (2023). EEG Lempel-Ziv complexity varies with sleep stage, but does not seem to track dream experience. Front. Hum. Neurosci., 16.","DOI":"10.3389\/fnhum.2022.987714"},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"ENEURO.0259-23.2024","DOI":"10.1523\/ENEURO.0259-23.2024","article-title":"Spectral Slope and Lempel-Ziv Complexity as Robust Markers of Brain States during Sleep and Wakefulness","volume":"11","author":"Hahn","year":"2024","journal-title":"eNeuro"},{"key":"ref_77","first-page":"1","article-title":"Low frequency oscillations drive EEG\u2019s complexity changes during wakefulness and sleep","volume":"494","author":"Mateos","year":"2022","journal-title":"Neuroscience"},{"key":"ref_78","first-page":"647","article-title":"Caffeine maintains vigilance and improves run times during night operations for Special Forces","volume":"76","author":"McLellan","year":"2005","journal-title":"Aviat. Space Environ. Med."},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"1193","DOI":"10.1016\/j.nut.2016.04.005","article-title":"Caffeine consumption, insomnia, and sleep duration: Results from a nationally representative sample","volume":"32","author":"Chaudhary","year":"2016","journal-title":"Nutrition"},{"key":"ref_80","doi-asserted-by":"crossref","first-page":"726","DOI":"10.1016\/j.nutres.2013.06.005","article-title":"Caffeine intake reduces sleep duration in adolescents","volume":"33","author":"Lodato","year":"2013","journal-title":"Nutr. Res."},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"899","DOI":"10.5665\/sleep.1942","article-title":"\u201cNo thanks, coffee keeps me awake\u201d: Individual caffeine sensitivity depends on ADORA2A genotype","volume":"35","author":"Landolt","year":"2012","journal-title":"Sleep"},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1111\/j.1365-2125.1986.tb05246.x","article-title":"Comparative pharmacokinetics of caffeine and its primary demethylated metabolites paraxanthine, theobromine and theophylline in man","volume":"22","author":"Lelo","year":"1986","journal-title":"Br. J. Clin. Pharmacol."},{"key":"ref_83","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1007\/s40279-014-0260-0","article-title":"Sleep and athletic performance: The effects of sleep loss on exercise performance, and physiological and cognitive responses to exercise","volume":"45","author":"Fullagar","year":"2015","journal-title":"Sports Med."},{"key":"ref_84","doi-asserted-by":"crossref","first-page":"S13","DOI":"10.1007\/s40279-014-0147-0","article-title":"Sleep in elite athletes and nutritional interventions to enhance sleep","volume":"44","author":"Halson","year":"2014","journal-title":"Sports Med."},{"key":"ref_85","doi-asserted-by":"crossref","first-page":"683","DOI":"10.1007\/s40279-017-0832-x","article-title":"Sleep Interventions Designed to Improve Athletic Performance and Recovery: A Systematic Review of Current Approaches","volume":"48","author":"Bonnar","year":"2018","journal-title":"Sports Med."},{"key":"ref_86","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1097\/BPO.0000000000000151","article-title":"Chronic lack of sleep is associated with increased sports injuries in adolescent athletes","volume":"34","author":"Milewski","year":"2014","journal-title":"J. Pediatr. Orthop."},{"key":"ref_87","doi-asserted-by":"crossref","first-page":"943","DOI":"10.5665\/SLEEP.1132","article-title":"The effects of sleep extension on the athletic performance of collegiate basketball players","volume":"34","author":"Mah","year":"2011","journal-title":"Sleep"},{"key":"ref_88","doi-asserted-by":"crossref","first-page":"1154","DOI":"10.1016\/j.neubiorev.2010.12.003","article-title":"The function of the sleep spindle: A physiological index of intelligence and a mechanism for sleep-dependent memory consolidation","volume":"35","author":"Fogel","year":"2011","journal-title":"Neurosci. Biobehav. Rev."},{"key":"ref_89","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1016\/S0896-6273(02)00746-8","article-title":"Practice with sleep makes perfect: Sleep-dependent motor skill learning","volume":"35","author":"Walker","year":"2002","journal-title":"Neuron"},{"key":"ref_90","doi-asserted-by":"crossref","first-page":"s683","DOI":"10.2741\/1064","article-title":"Mathematical models of sleep regulation","volume":"8","author":"Achermann","year":"2003","journal-title":"Front Biosci."},{"key":"ref_91","doi-asserted-by":"crossref","first-page":"483","DOI":"10.1016\/0013-4694(81)90225-X","article-title":"Sleep deprivation: Effect on sleep stages and EEG power density in man","volume":"51","author":"Baumann","year":"1981","journal-title":"Electroencephalogr. Clin. Neurophysiol."},{"key":"ref_92","doi-asserted-by":"crossref","unstructured":"Nishida, M., and Walker, M.P. (2007). Daytime naps, motor memory consolidation and regionally specific sleep spindles. PLoS ONE, 2.","DOI":"10.1371\/journal.pone.0000341"},{"key":"ref_93","first-page":"1149","article-title":"Motor sequence learning increases sleep spindles and fast frequencies in post-training sleep","volume":"31","author":"Morin","year":"2008","journal-title":"Sleep"},{"key":"ref_94","doi-asserted-by":"crossref","first-page":"94","DOI":"10.1080\/17461391.2014.932016","article-title":"Sleep\/wake behaviours of elite athletes from individual and team sports","volume":"15","author":"Lastella","year":"2015","journal-title":"Eur. J. Sport Sci."},{"key":"ref_95","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1016\/j.jsams.2014.02.007","article-title":"Understanding sleep disturbance in athletes prior to important competitions","volume":"18","author":"Juliff","year":"2015","journal-title":"J. Sci. Med. Sport"},{"key":"ref_96","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1080\/02640414.2014.942690","article-title":"Sleep\/wake behaviour of endurance cyclists before and during competition","volume":"33","author":"Lastella","year":"2015","journal-title":"J. Sports Sci."},{"key":"ref_97","doi-asserted-by":"crossref","first-page":"1387","DOI":"10.1007\/s40279-015-0358-z","article-title":"Stress, Sleep and Recovery in Elite Soccer: A Critical Review of the Literature","volume":"45","author":"Halson","year":"2015","journal-title":"Sports Med."},{"key":"ref_98","doi-asserted-by":"crossref","first-page":"681","DOI":"10.1136\/bjsports-2018-100278","article-title":"Wake up and smell the coffee: Caffeine supplementation and exercise performance-an umbrella review of 21 published meta-analyses","volume":"54","author":"Grgic","year":"2020","journal-title":"Br. J. Sports Med."},{"key":"ref_99","doi-asserted-by":"crossref","first-page":"S175","DOI":"10.1007\/s40279-014-0257-8","article-title":"Exercise and sport performance with low doses of caffeine","volume":"44","author":"Spriet","year":"2014","journal-title":"Sports Med."},{"key":"ref_100","doi-asserted-by":"crossref","unstructured":"Kocak, A., Georgousopoulou, E., Knight-Agarwal, C.R., Matthews, R., and Minehan, M. (2025). The Effect of Consuming Caffeine Before Late Afternoon\/Evening Training or Competition on Sleep: A Systematic Review with Meta-Analysis. Sports, 13.","DOI":"10.3390\/sports13090317"},{"key":"ref_101","doi-asserted-by":"crossref","unstructured":"Barnard, J., Roberts, S., Lastella, M., Aisbett, B., and Condo, D. (2022). The Impact of Dietary Factors on the Sleep of Athletically Trained Populations: A Systematic Review. Nutrients, 14.","DOI":"10.3390\/nu14163271"},{"key":"ref_102","doi-asserted-by":"crossref","unstructured":"Filip-Stachnik, A. (2022). Does Acute Caffeine Intake before Evening Training Sessions Impact Sleep Quality and Recovery-Stress State? Preliminary Results from a Study on Highly Trained Judo Athletes. Appl. Sci., 12.","DOI":"10.3390\/app12199957"},{"key":"ref_103","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1007\/s40279-017-0776-1","article-title":"Are the Current Guidelines on Caffeine Use in Sport Optimal for Everyone? Inter-individual Variation in Caffeine Ergogenicity, and a Move Towards Personalised Sports Nutrition","volume":"48","author":"Pickering","year":"2018","journal-title":"Sports Med."},{"key":"ref_104","doi-asserted-by":"crossref","first-page":"623","DOI":"10.1016\/j.sleh.2020.01.016","article-title":"Subjective and objective sleep differ in male and female collegiate athletes","volume":"6","author":"Carter","year":"2020","journal-title":"Sleep Health"},{"key":"ref_105","doi-asserted-by":"crossref","first-page":"1487","DOI":"10.1007\/s40279-019-01119-4","article-title":"Sleep Monitoring in Athletes: Motivation, Methods, Miscalculations and Why it Matters","volume":"49","author":"Halson","year":"2019","journal-title":"Sports Med."},{"key":"ref_106","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1186\/s40798-018-0140-5","article-title":"The Clinical Validation of the Athlete Sleep Screening Questionnaire: An Instrument to Identify Athletes that Need Further Sleep Assessment","volume":"4","author":"Bender","year":"2018","journal-title":"Sports Med. Open"},{"key":"ref_107","doi-asserted-by":"crossref","first-page":"425","DOI":"10.1007\/BF00544361","article-title":"Impairment of caffeine clearance by chronic use of low-dose oestrogen-containing oral contraceptives","volume":"28","author":"Abernethy","year":"1985","journal-title":"Eur. J. Clin. Pharmacol."},{"key":"ref_108","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s00213-004-2000-x","article-title":"A critical review of caffeine withdrawal: Empirical validation of symptoms and signs, incidence, severity, and associated features","volume":"176","author":"Juliano","year":"2004","journal-title":"Psychopharmacology"}],"container-title":["Nutrients"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6643\/18\/8\/1220\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,23]],"date-time":"2026-04-23T09:16:46Z","timestamp":1776935806000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6643\/18\/8\/1220"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,13]]},"references-count":108,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2026,4]]}},"alternative-id":["nu18081220"],"URL":"https:\/\/doi.org\/10.3390\/nu18081220","relation":{},"ISSN":["2072-6643"],"issn-type":[{"value":"2072-6643","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,13]]}}}