Journal of caffeine research最新文献

{"title":"Combined Effects of Ephedrine-Containing Dietary Supplements, Caffeine, and Nicotine on Morphology and Ultrastructure of Rat Hearts.","authors":"Christopher E Brown,&nbsp;Stanley E Trauth,&nbsp;Richard S Grippo,&nbsp;Bill J Gurley,&nbsp;Anne A Grippo","doi":"10.1089/jcr.2012.0021","DOIUrl":"https://doi.org/10.1089/jcr.2012.0021","url":null,"abstract":"<p><p>Cigarette smokers have an increased risk for coronary artery disease. Nicotine present in cigarettes can adversely affect the cardiovascular system via stimulation of both sympathetic and parasympathetic neurons. Caffeine, another cardiovascular and central nervous system (CNS) stimulant, is commonly found in <i>Ephedra</i> and <i>Ephedra</i>-free dietary supplements. These caffeine-containing supplements also have been linked to cardiovascular toxicities. Although no longer on the U.S market, <i>Ephedra</i>-containing supplements are another source of cardiovascular and CNS stimulants, namely the ephedrine alkaloids. Together caffeine, nicotine, and ephedrine can individually stress the cardiovascular system, and an overlap of these agents is predicted in smokers and dieters. To understand the collective effects of these stimulants on the heart morphology and ultrastructure, rats were exposed to synthetic combinations of nicotine (0.2 mg/kg/day), ephedrine (0-30 mg/kg/day), and/or caffeine (0-24 mg/kg/day) as well as an extract from a caffeine-containing <i>Ephedra</i> supplement (Metabolife 356). After exposure for 3 days, the hearts were removed and examined for hypersensitivity myocarditis and myocardial necrosis. None of the drugs tested alone affected heart tissue morphology, nor were atypical cardiac cells observed. However, in combination, significant interactions were found between caffeine and ephedrine; the interventricular septum was most susceptible, with a significant increase in atypical cardiac cells observed. Nicotine pretreatment caused greater susceptibility to cardiotoxicity associated with combinations of caffeine + ephedrine or Metabolife, particularly in the left ventricle wall. These results indicate that sympathomimetic combinations present in <i>Ephedra</i> supplements may have produced cardiotoxicity reported in consumers of these products. Moreover, the presence of nicotine exacerbates these toxic effects.</p>","PeriodicalId":89685,"journal":{"name":"Journal of caffeine research","volume":"2 3","pages":"123-132"},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/jcr.2012.0021","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32288439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Alcohol, Coffee, and Tobacco, Alone or in Combination, on Physiological Parameters and Anxiety in a Young Population.","authors":"Concepción Vinader-Caerols,&nbsp;Santiago Monleón,&nbsp;Carmen Carrasco,&nbsp;Andres Parra","doi":"10.1089/jcr.2012.0018","DOIUrl":"https://doi.org/10.1089/jcr.2012.0018","url":null,"abstract":"<p><strong>Objective: </strong>The objective was to evaluate the effects of a single dose of alcohol, caffeine, and nicotine, alone or in combination, on physiological parameters (systolic and diastolic blood pressure [SBP and DBP] and heart rate [HR]) and state-trait anxiety in healthy young volunteers.</p><p><strong>Method: </strong>The procedure reproduces the conditions under which the subjects (<i>n</i>=76) usually ingest alcohol (through an alcoholic beverage), caffeine (through a cup of coffee), and nicotine (by smoking a cigarette), separately or in combination, according to their consumption habits of each individual. SBP and DBP, HR, and state anxiety (SA) were registered before (phase 1) and after (phase 2) treatment.</p><p><strong>Results: </strong>Intake of alcohol or alcohol-nicotine reduced DBP. Comparisons between control and combined treatment (coffee-alcohol-nicotine) groups revealed a decrease in HR in the former group but not in the latter. The coffee consumers alone exhibited a tendency toward an increase in SA, while the control group showed a tendency toward a decrease in this measure. When Phase 1 and Phase 2 were compared, a decrease was observed in SBP (alcohol and coffee-alcohol groups), DBP (alcohol and alcohol-nicotine groups), HR (all groups, except coffee-alcohol and coffee-alcohol-nicotine groups), and SA (coffee-alcohol-nicotine group).</p><p><strong>Conclusions: </strong>(i) A low dose of alcohol, either alone or in combination with a cigarette, decreases DBP but not SBP; (ii) the polyconsumption of coffee, alcohol, and nicotine blocks the adaptation response (the reduction in HR in control subjects in the second phase); (iii) an increase of SA is observed after consuming coffee, while the opposite occurs in control subjects (a decrease of SA).</p>","PeriodicalId":89685,"journal":{"name":"Journal of caffeine research","volume":"2 2","pages":"70-76"},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/jcr.2012.0018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32286926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differential Effect of Caffeine Consumption on Diverse Brain Areas of Pregnant Rats.","authors":"Inmaculada Ballesteros-Yáñez,&nbsp;Carlos Alberto Castillo,&nbsp;Mariano Amo-Salas,&nbsp;José Luis Albasanz,&nbsp;Mairena Martín","doi":"10.1089/jcr.2012.0011","DOIUrl":"https://doi.org/10.1089/jcr.2012.0011","url":null,"abstract":"<p><strong>Background: </strong>It has previously been shown that during gestation, the mother's brain has an increase in glial fibrillary acidic protein (GFAP)-immunoreactivity (-ir) and a decrease in the mRNA level of A1 adenosine receptor. Little is known about the A2A adenosine receptor in the maternal brain, and whether caffeine consumption throughout gestational period modifies GFAP and adenosine receptor density in specific brain areas. This study was undertaken to investigate the protein density of GFAP and adenosine receptors (A1 and A2A subtypes) in different regions of pregnant rat brain and the possible effect of caffeine on these proteins.</p><p><strong>Methods: </strong>For this purpose, we examined the GFAP-, A1- and A2A-ir in the cingulate cortex (Cg2), dentate gyrus (DG), medial preoptic area (mPOA), secondary somatosensory cortex (S2), and striatum (Str) of pregnant Wistar rats (drug-free tap water or water with 1g/L diluted caffeine).</p><p><strong>Results: </strong>We show a consistent and highly significant reduction of GFAP-ir in caffeine-treated pregnant rats in most of the areas analyzed. Our data demonstrate that caffeine consumption induces a significant increase of A2A-ir in Str. Concerning A1 receptor, the observed changes are dependent on the region analyzed; this receptor density is increased in Cg2, DG, and mPOA and decreased in the somatosensory cortex and Str. The results were confirmed by Western blotting.</p><p><strong>Conclusions: </strong>Our results suggest that chronic caffeine exposure could modify the physiolological situation of gestation by a reorganization of the neural circuits and the adenosine neuromodulator system.</p>","PeriodicalId":89685,"journal":{"name":"Journal of caffeine research","volume":"2 2","pages":"90-98"},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/jcr.2012.0011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32286928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alcohol Mixed with Energy Drink Use and Sexual Risk-Taking: Casual, Intoxicated, and Unprotected Sex.","authors":"Kathleen E Miller","doi":"10.1089/jcr.2012.0015","DOIUrl":"10.1089/jcr.2012.0015","url":null,"abstract":"<p><strong>Objective: </strong>This study examined the confluence of several behaviors common to U.S. young adults: caffeinated energy drink use, alcohol use, and sexual risk-taking. The author examined relationships between the use of energy drinks mixed with alcohol (AmEDs) and three sexual risk behaviors: casual sex (i.e., intercourse with a nonexclusive and/or nonromantic partner), intoxicated sex (i.e., intercourse while under the influence of alcohol and/or illicit drugs), and unprotected sex (i.e., intercourse without use of a condom).</p><p><strong>Method: </strong>Logistic regression analyses were employed to analyze data from a cross-sectional survey of 648 sexually active undergraduate students at a large public university.</p><p><strong>Results: </strong>After controlling for risk-taking norms and frequency of noncaffeinated alcohol use, AmED use was associated with elevated odds of casual sex and intoxicated sex but not unprotected sex.</p><p><strong>Conclusions: </strong>Although further studies are needed to test for event-level relationships, AmED use should be considered a possible risk factor for potentially health-compromising sexual behaviors.</p>","PeriodicalId":89685,"journal":{"name":"Journal of caffeine research","volume":"2 2","pages":"62-69"},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3621311/pdf/jcr.2012.0015.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32286925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Caffeine Enhances Heart Rate Variability in Middle-Aged Healthy, But Not Heart Failure Subjects.","authors":"Catherine F Notarius,&nbsp;John S Floras","doi":"10.1089/jcr.2012.0010","DOIUrl":"https://doi.org/10.1089/jcr.2012.0010","url":null,"abstract":"<p><strong>Background: </strong>In chronic heart failure (CHF) due to left ventricular dysfunction, diminished heart rate variability (HRV) is an independent predictor of poor prognosis. Caffeine has been shown to increase HRV in young healthy subjects. Such an increase may be of potential benefit to patients with CHF.</p><p><strong>Objective: </strong>We hypothesized that intravenous infusion of caffeine would increase HRV in CHF, and in age-matched healthy control subjects.</p><p><strong>Methods: </strong>On two separate days, 11 patients (1F) with CHF (age=51.3±4.6 years; left ventricular ejection fraction=18.6±2.7%; mean±standard error) and 10 healthy control subjects (age=48.0±4.0) according to a double-blind randomization design, received either saline or caffeine (4 mg/kg) infusion. We assessed HRV over 7 minutes of supine rest (fast Fourier Transform analysis) to determine total spectral power as well as its high-frequency (HF) (0.15-0.50 Hz) and low-frequency (LF) (0.05-0.15 Hz) components, and recorded muscle sympathetic nerve activity (MSNA) directly from the peroneal nerve (microneurography).</p><p><strong>Results: </strong>In healthy control subjects, compared with saline, caffeine reduced both heart rate and sympathetic nerve traffic (<i>p</i>≤0.003) and increased the ratio of HF/total power (<i>p</i>≤0.05). Baseline LF power and the ratio LF/HF were significantly lower in CHF compared with controls (<i>p</i>=0.02), but caffeine had no effect on any element of HRV.</p><p><strong>Conclusions: </strong>Caffeine increases cardiac vagal heart rate modulation and reduces MSNA in middle-aged healthy subjects, but not in those with CHF.</p>","PeriodicalId":89685,"journal":{"name":"Journal of caffeine research","volume":"2 2","pages":"77-82"},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/jcr.2012.0010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32286927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pilot Study of Caffeine Abstinence for Control of Chronic Glucose in Type 2 Diabetes.","authors":"James D Lane,&nbsp;Alex J Lane,&nbsp;Richard S Surwit,&nbsp;Cynthia M Kuhn,&nbsp;Mark N Feinglos","doi":"10.1089/jcr.2012.0003","DOIUrl":"https://doi.org/10.1089/jcr.2012.0003","url":null,"abstract":"<p><p>BACKGROUND: A growing body of evidence suggests that caffeinated beverages may impair chronic glucose control in type 2 diabetes. This pilot study tested the chronic effects of caffeine abstinence on glucose control in type 2 diabetic patients who were daily coffee drinkers. METHODS: Twelve coffee drinkers (six males) with established type 2 diabetes participated. Seven (five males) completed 3 months of total caffeine abstinence. Measures of chronic glucose control, long-term (hemoglobin A1c [HbA1c]) and short-term (1,5-anhydroglucitol [1,5-AG]), were collected at baseline and during follow-up. Abstinence was established by diaries confirmed by saliva caffeine assays. RESULTS: Abstinence produced significant decreases in HbA1c and increases in 1,5-AG, both indicating improvements in chronic glucose control. Fasting glucose and insulin did not change, nor were changes in body weight observed. CONCLUSIONS: Although preliminary, these results suggest that caffeine abstinence may be beneficial for patients with type 2 diabetes. This hypothesis should be confirmed in larger controlled clinical trials.</p>","PeriodicalId":89685,"journal":{"name":"Journal of caffeine research","volume":"2 1","pages":"45-47"},"PeriodicalIF":0.0,"publicationDate":"2012-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/jcr.2012.0003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31094672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Effects of Dietary Caffeine Use and Abstention on Blood Oxygen Level-Dependent Activation and Cerebral Blood Flow.","authors":"Merideth A Addicott,&nbsp;Ann M Peiffer,&nbsp;Paul J Laurienti","doi":"10.1089/jcr.2011.0027","DOIUrl":"https://doi.org/10.1089/jcr.2011.0027","url":null,"abstract":"<p><strong>Background: </strong>Caffeine is a known vasoconstrictor that reduces resting cerebral blood flow (CBF) throughout the brain. This effect may be problematic in functional magnetic resonance imaging (fMRI) research, as the blood oxygen level-dependent (BOLD) signal is a complex interaction of CBF and other factors that are dependent on changes in neural activity. It is unknown whether changes in the BOLD signal during an fMRI experiment could be affected by subjects' recent use or abstinence from dietary caffeine.</p><p><strong>Methods: </strong>Here, we report two similar studies (<i>n</i>=45 and 17) that measure the effects of caffeine on BOLD activation, BOLD time course parameters, and CBF. Using a factorial design, low, moderate, and high caffeine consumers received either caffeine (250 mg) or placebo during normal caffeine use (satiated state) or after 30 hours of abstention (abstinent state). The fMRI of a reaction time task and resting-state CBF were collected.</p><p><strong>Results: </strong>In general, acute caffeine administration reduced the time to peak and full width at half maximum of the BOLD time course, and CBF across both studies. Caffeine also produced a small reduction in BOLD activation. The majority of these reductions across measures were moderated by neither the level of caffeine use, nor the abstinent or satiated state.</p><p><strong>Conclusions: </strong>These results suggest that dietary caffeine use does not produce a significant effect on task-related BOLD activation.</p>","PeriodicalId":89685,"journal":{"name":"Journal of caffeine research","volume":"2 1","pages":"15-22"},"PeriodicalIF":0.0,"publicationDate":"2012-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/jcr.2011.0027","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32286924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating Dependence Criteria for Caffeine.","authors":"Catherine L W Striley,&nbsp;Roland R Griffiths,&nbsp;Linda B Cottler","doi":"10.1089/jcr.2011.0029","DOIUrl":"https://doi.org/10.1089/jcr.2011.0029","url":null,"abstract":"<p><p><b><i>Background:</i></b> Although caffeine is the most widely used mood-altering drug in the world, few studies have operationalized and characterized Diagnostic and Statistical Manual IV (DSM-IV) substance dependence criteria applied to caffeine. <b><i>Methods:</i></b> As a part of a nosological study of substance use disorders funded by the National Institute on Drug Abuse, we assessed caffeine use and dependence symptoms among high school and college students, drug treatment patients, and pain clinic patients who reported caffeine use in the last 7 days and also reported use of alcohol, nicotine, or illicit drugs within the past year (<i>n</i>=167). <b><i>Results:</i></b> Thirty-five percent met the criteria for dependence when all seven of the adopted DSM dependence criteria were used. Rates of endorsement of several of the most applicable diagnostic criteria were as follows: 26% withdrawal, 23% desire to cut down or control use, and 44% continued use despite harm. In addition, 34% endorsed craving, 26% said they needed caffeine to function, and 10% indicated that they talked to a physician or counselor about problems experienced with caffeine. There was a trend towards increased caffeine dependence among those dependent on nicotine or alcohol. Within a subgroup that had used caffeine, alcohol, and nicotine in the past year, 28% fulfilled criteria for caffeine dependence compared to 50% for alcohol and 80% for nicotine. <b><i>Conclusion:</i></b> The present study adds to a growing literature suggesting the reliability, validity, and clinical utility of the caffeine dependence diagnosis. Recognition of caffeine dependence in the DSM-V may be clinically useful.</p>","PeriodicalId":89685,"journal":{"name":"Journal of caffeine research","volume":"1 4","pages":"219-225"},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/jcr.2011.0029","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32286923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alcohol and Caffeine: The Perfect Storm.","authors":"Sergi Ferré,&nbsp;Mary Claire O'Brien","doi":"10.1089/jcr.2011.0017","DOIUrl":"https://doi.org/10.1089/jcr.2011.0017","url":null,"abstract":"<p><p>Although it is widely believed that caffeine antagonizes the intoxicating effects of alcohol, the molecular mechanisms underlying their interaction are incompletely understood. It is known that both caffeine and alcohol alter adenosine neurotransmission, but the relationship is complex, and may be dose dependent. In this article, we review the available literature on combining caffeine and alcohol. Ethical constraints prohibit laboratory studies that would mimic the high levels of alcohol intoxication achieved by many young people in real-world settings, with or without the addition of caffeine. We propose a possible neurochemical mechanism for the increase in alcohol consumption and alcohol-related consequences that have been observed in persons who simultaneously consume caffeine. Caffeine is a nonselective adenosine receptor antagonist. During acute alcohol intake, caffeine antagonizes the \"unwanted\" effects of alcohol by blocking the adenosine A₁ receptors that mediate alcohol's somnogenic and ataxic effects. The A₁ receptor-mediated \"unwanted\" anxiogenic effects of caffeine may be ameliorated by alcohol-induced increase in the extracellular concentration of adenosine. Moreover, by means of interactions between adenosine A_2A and dopamine D₂ receptors, caffeine-mediated blockade of adenosine A_2A receptors can potentiate the effects of alcohol-induced dopamine release. Chronic alcohol intake decreases adenosine tone. Caffeine may provide a \"treatment\" for the withdrawal effects of alcohol by blocking the effects of upregulated A₁ receptors. Finally, blockade of A_2A receptors by caffeine may contribute to the reinforcing effects of alcohol.</p>","PeriodicalId":89685,"journal":{"name":"Journal of caffeine research","volume":"1 3","pages":"153-162"},"PeriodicalIF":0.0,"publicationDate":"2011-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/jcr.2011.0017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32286922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gender Differences in Subjective and Physiological Responses to Caffeine and the Role of Steroid Hormones.","authors":"Jennifer L Temple,&nbsp;Amanda M Ziegler","doi":"10.1089/jcr.2011.0005","DOIUrl":"https://doi.org/10.1089/jcr.2011.0005","url":null,"abstract":"<p><strong>Background: </strong>We have shown previously that male and female adolescents differ in their responses to caffeine, but to date, the mechanisms underlying these gender differences are unknown.</p><p><strong>Objective: </strong>The purpose of this study was to test the hypothesis that differences in circulating steroid hormones mediate gender differences in response to caffeine.</p><p><strong>Methods: </strong>Subjective and physiological responses to caffeine were tested in adolescents using a double-blind, placebo controlled, crossover design. Participants were tested every 2 weeks for 8 weeks and received placebo and caffeine (2 mg/kg) twice each. Females were tested with placebo and caffeine in each phase of their menstrual cycle. Salivary concentrations of testosterone, estradiol, and progesterone were also measured.</p><p><strong>Results: </strong>Males showed greater positive subjective effects than females. In females, higher levels of estradiol were associated with little or no subjective responses to caffeine, but lower levels of estradiol were associated with negative subjective responses to caffeine relative to placebo. There were gender differences in cardiovascular responses to caffeine, with males showing greater decreases in heart rate after caffeine administration than females, but females showing greater increases in diastolic blood pressure than males after caffeine administration. These gender differences may be related to steroid hormone concentrations. Blood pressure responses to caffeine were lower in males when estradiol was high, but higher in females when estradiol was high.</p><p><strong>Conclusions: </strong>When taken together, these findings suggest that males and females differ in their responses to caffeine and that these differences may be mediated by changes in circulating steroid hormones.</p>","PeriodicalId":89685,"journal":{"name":"Journal of caffeine research","volume":"1 1","pages":"41-48"},"PeriodicalIF":0.0,"publicationDate":"2011-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/jcr.2011.0005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32286921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}