Short-term effects of espresso coffee on heart rate variability and blood pressure in habitual and non-habitual coffee consumers – A randomized crossover study

dP roo f

Frank Zimmermann-Viehoff 1,2 , Julian Thayer 3, Julian Koenig 3, Christian Herrmann 2, Cora S. Weber 2, Hans-Christian Deter 2 1

Department of Psychiatry and Psychotherapy, Charité University Medical Center, Berlin, Germany, Department of Psychosomatic Medicine and Psychotherapy, Charité University Medical Center, Berlin, Germany, 3Department of Psychology, Ohio State University, Columbus, USA 2

rre

cte

Objective: Coffee is one of the most widely consumed beverages worldwide. Aim of this study was to investigate short-term effects of espresso coffee on heart rate variability (HRV), a marker of vagal activity, in healthy habitual and non-habitual coffee consumers. Methods: Seventy-seven healthy subjects (38 habitual and 39 non-habitual coffee consumers, 74% women, mean age 26.97 ± 6.88 years) took part in three laboratory sessions in a randomized order. In condition 1, subjects consumed espresso; in condition 2, subjects consumed decaffeinated espresso; and in condition 3, subjects consumed warm water. HRV and blood pressure were assessed at rest before and after ingestion of the respective beverage. Results: HRV was significantly increased after consumption of caffeinated espresso, decaffeinated espresso, or water, indicating increased vagal activity in the course of the experiments. In the habitual coffee consumers, the increase in vagally mediated HRV was significantly lower after consumption of decaffeinated espresso compared to caffeinated espresso. Increases of systolic blood pressure were only found in the non-habitual consumers. Conclusion: We found no evidence for specific short-term effects of caffeinated espresso on vagal activity in healthy subjects. Instead, consumption of decaffeinated espresso inhibited vagal activity in habitual consumers. This may be explained by an attempt of the organism to establish a sympathovagal equilibrium comparable to that after caffeine consumption. In the absence of caffeine-induced sympathetic activation, this may have been achieved by relative vagal withdrawal.

Introduction

co

Keywords: Coffee, Caffeine, Autonomic nervous system, Heart rate variability, Blood pressure

Un

Coffee is one of the most widely consumed beverages worldwide. Despite concerns with respect to a potentially increased cardiovascular risk associated with coffee consumption in the past, more recent metaanalyses show that regular coffee consumption is associated with reduced risks of type 2 diabetes,1 cardiovascular disease,2,3 and all-cause mortality.4,5 Coffee is reported to contain more than a thousand bioactive compounds.6 Caffeine, considered to be the major active ingredient, is a purine alkaloid that appears to exert most of its biological effects through the antagonism of the A1 and A2 subtypes of the Correspondence to: Frank Zimmermann-Viehoff, Department of Psychiatry and Psychotherapy, Charité University Medical Center, Campus Benjamin Franklin, Eschenallee 3, 14050 Berlin, Germany. Email: [email protected]

© W. S. Maney & Son Ltd 2015 DOI 10.1179/1476830515Y.0000000018

adenosine receptor.6 Effects of caffeine on autonomic nervous system activity are mostly described as sympathomimetic. Caffeine acutely increases sympathetic nerve outflow,7 circulating catecholamine concentrations,8,9 plasma renin activity,9 and blood pressure (BP).7,8,10 However, the BP effects of caffeine were shown to habituate rapidly within 3–5 days.11,12 Influences of coffee or caffeine to the parasympathetic branch of the autonomic nervous system are less extensively investigated. Heart rate variability (HRV) is an established marker of parasympathetic (vagal) activity and predicts cardiovascular morbidity and mortality.13 Additionally, HRV is closely related to changes in immune and metabolic function.14,15 Because a number of previous studies indicate changes of HRV

Nutritional Neuroscience

2015

VOL.

0

NO.

0

1

Short-term effects of espresso coffee on heart rate variability and blood pressure

committee of the Charité University Medical Center, and written informed consent was obtained from all participants.

Study protocol The study utilizes a three-arm within-subjects crossover design. Each participant took part in three laboratory sessions in a randomized order. In condition 1 subjects consumed a triple espresso, in condition 2 subjects consumed an equivalent amount of decaffeinated espresso, and in condition 3 subjects consumed an equivalent amount of warm water. There was an interval of at least 48 hours between the sessions. The experimenter (CH) and all subjects were blinded with respect to caffeine content of the espresso preparations. All laboratory sessions started either at 8 a.m. or 10 a.m. One subject was always tested at the same time at all three occasions. The sessions took place at the Charité Medical Center Berlin in a quiet room with an ambient temperature of 20–24°C. Subjects were instructed not to consume caffeine-containing beverages 12 hours before testing. After arrival in the laboratory, participants were seated in a comfortable, high-backed chair and the instruments for heart rate and BP measurement were attached. The session started with a 20-minute resting period (baseline), during which the subjects were allowed to read newspapers or light magazines to avoid rumination effects. After that, subjects were served a freshly prepared triple espresso, a triple decaffeinated espresso, or an equivalent amount of warm water. Subjects were given a maximum of 10 minutes to consume the respective beverage. Thereafter, subjects rested for another 50 minutes while they were allowed to read.

rre

cte

related to caffeine consumption, potential effects of caffeine on HRV may be an important pathway by which coffee consumption affects health. A recent systematic review16 concluded that evidence on the impact of caffeine on HRV is still not clear. Shortterm increases in high frequency (HF) power of HRV were observed in five of the identified studies,17–21 suggesting that caffeine may increase parasympathetic activity. However, one of these studies found significant changes of HF power only in the supine position,18 one study found significant changes of HF power only during exercise,19 and one study found significant changes of HF power only in type 1 diabetic subjects and not in healthy controls.21 Two studies observed no significant changes of HRV at all,22,23 and one study reported even decreased HF power after 100 and 200 mg of caffeine.24 These differences are likely due to the heterogeneity in study designs, populations under investigation, controlling for confounders, and caffeine dosages. Most importantly, most studies did not differentiate between habitual and non-habitual coffee consumers. Aim of this study therefore was to investigate shortterm effects of a triple espresso on HRV in healthy habitual and non-habitual coffee consumers, using a randomized three-session crossover design (consumption of espresso, decaffeinated espresso, or water). Based on previous findings of short-term increases of HF power of HRV, we hypothesized that habitual coffee consumers would show a larger increase in vagal activity as indexed by HF power of HRV after consumption of caffeinated espresso compared to decaffeinated espresso and water, and that this difference would not be found in non-habitual consumers.

dP roo f

Zimmermann-Viehoff et al.

Methods Subjects

Un

co

A priori sample size calculation based on data of an unpublished pilot study at the Charité Medical Center Berlin revealed that 36 habitual coffee consumers would be needed to detect a significant difference in HRV responses after ingestion of caffeinated espresso versus decaffeinated espresso at a significance level of P < 0.05, with a power of 90%. Accounting for possible dropouts, 38 habitual consumers and 39 nonhabitual consumers were enrolled. Healthy subjects between 18 and 50 years were recruited by postings at local universities. Habitual coffee consumption was defined as daily coffee consumption, and nonhabitual coffee consumption was defined non-daily coffee consumption. Exclusion criteria were presence of any physical or mental disease, intake of medications, substance use, current smoking, obesity (body mass index >30 kg/m2), current participation in another study, and known hypersensitivity to caffeine. The study protocol was approved by the ethics

2

Nutritional Neuroscience

2015

VOL.

0

NO.

0

Espresso preparation

Espresso was prepared using a Jura® E75A fully automatic Espresso machine. One hundred percent Arabica coffee beans were used for caffeinated and decaffeinated espresso. For decaffeinated espresso, ‘Swiss water method’ heated beans were used. A triple espresso corresponded to a volume of 120 ml. Adding sugar or milk was not allowed to prevent possible effects on absorption. After every delivery, the espresso machine was irrigated with water. Caffeine content was analyzed by high-performance liquid chromatography from three random samples of caffeinated and decaffeinated espresso. The mean caffeine concentration of caffeinated espresso was 2.14 mg/ml (standard deviation 0.055), corresponding to a total amount of 256.80 mg of caffeine per cup. The mean caffeine concentration of decaffeinated espresso was 0.30 mg/ml (standard deviation 0.07), corresponding to a total amount of 36.00 mg of

Zimmermann-Viehoff et al.

Short-term effects of espresso coffee on heart rate variability and blood pressure

caffeine per cup. For comparison, a study in the USA found that the amount of caffeine in 240 ml of brewed coffee ranged from 72 to 130 mg, and the amount of caffeine in a single shot of espresso ranged from 58 to 76 mg.25

Results

Data from a total of 77 participants (57 females) were available for analysis. Characteristics of the sample are shown in Table 1. Analyses revealed no significant differences regarding any of the included sociodemographic variables between habitual and non-habitual coffee consumers, except for age (t (75) = 2.244, P = 0.029), indicating that habitual coffee consumers were older. Independent t-tests revealed no significant differences regarding any of the physiological variables before consumption of water, decaffeinated, or caffeinated espresso between groups (all P > 0.05). Also, there were no significant differences regarding any of the physiological variables after consumption

Un

co

rre

cte

Heart rate (HR) was continuously recorded using a Polar© HR monitor (Polar RS800CX). Data from the Polar device were transferred to a PC using the Polar electro interface. Prior to HRV analysis, the measured RR interval data were preprocessed for artifacts using the Polar Precision Performance™ software that came with the heart rate monitor. Analysis of HRV was performed using Kubios® HRV version 2.0 software.26 We calculated the root-mean square of differences between adjacent normal RR-intervals (RMSSD), HF power, and low frequency (LF) power according to standard methods. RMSSD and HF power of HRV mainly represent vagally mediated parasympathetic activity, with higher values indicating higher parasympathetic activity. LF power of HRV is influenced by both parasympathetic and sympathetic activity. The LF/HF ratio is often regarded as a measure of sympathovagal balance. However, as for the LF power of HRV, the LF/HF ratio should be interpreted with caution, as the exact contributing factors are not fully understood.27 Although vagally mediated parasympathetic activity is the major contributor to HRV, particularly regarding HF power and RMSSD, it should be noted that other factors, for example breathing frequency, may also influence HRV measures.27 All HRV values were logarithmically transformed before the analysis to achieve normal distribution. BP was measured using an automatic oscillometric device (Dinamp™, Criticon, Tampa, FL, USA) on the left arm at 1-minute intervals during the complete recording period as elsewhere described.28–31 Pulse pressure (PP) was calculated by subtracting diastolic blood pressure (DBP) from systolic blood pressure (SBP). HRV was analyzed over the first 20 minutes of recording (baseline) and over 20 minutes starting 30 minutes after espresso consumption. Accordingly, SBP and DBP values of the single measurements were averaged over the first 20 minutes of recording (baseline) and over 20 minutes starting 30 minutes after espresso consumption. This time frame was chosen because caffeine reaches peak plasma concentrations 30–45 minutes after coffee ingestion.32,33

dP roo f

Assessment of physiological parameters

using chi-square tests for categorical variables, and independent t-test for continuous variables. HF power of HRV was the main outcome parameter. Repeated-measures ANOVA was employed to test for main effects of within-subjects factors time (2; pre and post), and condition (3; water, decaffeinated espresso, and espresso), as well as between-subjects factor group (2; habitual consumption and non-habitual consumption), and their interaction. As Mauchly’s test revealed a violation of sphericity, Greenhouse Geisser corrected P-values are reported for main and interaction within subjects effects (time and condition). Between-subjects effects from repeated measures on physiological variables were derived for main effects of habitual vs. non-habitual caffeine consumption. Relative changes (Δ) in physiological variables were analyzed calculating the difference between pre- and post-measures. Differences on these relative changes between conditions and groups based on habitual or non-habitual coffee consumers were analyzed using dependent (within group between condition) or independent t-test (between groups) as applicable.

Statistical analysis Descriptive statistics were expressed as means and standard deviations (SD). Differences between habitual and non-habitual coffee consumers were analyzed

Table 1 Demographic characteristics of habitual and non-habitual caffeine consumers

Variable N (%) Male, n (%) Female, n (%) Age, mean years (SD) Height, mean cm (SD) Weight, mean kg (SD) BMI, mean kg/m2 (SD)

Habitual consumers (HC)

Non-habitual consumers (NHC)

38 (49.4) 8 (21.1) 30 (78.9)

39 (50.6) 12 (30.8) 27 (69.2)

0.437

28.71 (7.65)

25.28 (5.63)

0.029

171.66 (8.38)

172.79 (9.12)

0.570

66.18 (11.22)

65.26 (10.22)

0.706

22.35 (2.56)

21.77 (2.18)

0.288

P

P refers to differences between habitual and non-habitual caffeine consumers, based on chi-square test for categorical variables, and independent t-tests for continuous variables. SD, standard deviation.

Nutritional Neuroscience

2015

VOL.

0

NO.

0

3

Zimmermann-Viehoff et al.

Baseline values and relative change scores on cardiovascular measures by condition and group HC

Group Condition HR (bpm), baseline Relative change SBP (mmHg), baseline Relative change DBP (mmHg), baseline Relative change PP (mmHg), baseline Relative change RMSSD (log), baseline Relative change HF (log), baseline Relative change LF (log), baseline Relative change LF/HF (log), baseline Relative change

NHC

Water

Decaff

Espresso

Water

Decaff

Espresso

75.33 (10.16) −3.22 (3.09) 107.05 (8.61) −1.66 (2.75) 65.35 (6.25) −1.74 (4.95) 41.70 (7.56) 2.82 (4.56) 3.46 (0.61) 0.22 (0.27) 5.23 (1.26) 0.36 (0.58) 5.96 (0.92) 0.46 (0.42) 1.17 (0.19) 0.00 (0.10)

74.50 (10.50) −1.58 (4.39) 107.42 (7.96) −2.69 (3.55) 64.54 (6.75) −4.94 (4.34) 42.88 (6.94) 2.25 (4.35) 3.55 (0.65) 0.12 (0.27) 5.49 (1.27) 0.17 (0.57) 5.98 (0.90) 0.44 (0.49) 1.12 (0.20) 0.04 (0.09)

73.96 (10.02) −2.58 (4.20) 107.74 (9.46) −1.74 (3.40) 64.62 (6.24) −4.00 (4.59) 43.12 (7.92) 2.26 (4.80) 3.53 (0.59) 0.23 (0.27) 5.33 (1.12) 0.47 (0.53) 5.88 (0.75) 0.46 (0.56) 1.14 (0.19) −0.02 (0.11)

75.11 (9.63) −2.93 (3.96) 107.54 (8.03) −2.80 (3.54) 63.51 (6.32) −4.69 (3.73) 44.03 (6.91) 1.88 (3.75) 3.57 (0.59) 0.20 (0.30) 5.43 (1.15) 0.43 (0.57) 5.95 (0.87) 0.50 (0.45) 1.12 (0.15) 0.00 (0.08)

75.43 (9.52) −2.27 (4.56) 108.27 (8.52) −2.17 (3.83) 64.26 (5.72) −4.66 (3.35) 44.01 (7.82) 2.48 (3.97) 3.49 (0.58) 0.17 (0.27) 5.30 (1.15) 0.38 (0.56) 5.95 (0.83) 0.35 (0.36) 1.15 (0.17) −0.03 (0.09)

73.85 (9.76) −2.52 (4.48) 108.54 (8.16) 0.81 (4.68) 65.04 (5.78) −3.36 (4.55) 43.50 (7.19) 4.17 (4.76) 3.62 (0.56) 0.20 (0.30) 5.56 (1.10) 0.40 (0.58) 6.06 (0.89) 0.34 (0.47) 1.11 (0.13) −0.02 (0.10)

dP roo f

Table 2

Short-term effects of espresso coffee on heart rate variability and blood pressure

All values are means and standard deviations (SD) in brackets; log: natural log-transformed values.

habitual coffee consumers after the consumption of decaffeinated espresso (t (73) = 3.378, P = 0.001). While the LF/HF ratio increased in habitual consumers, it decreased in non-habitual consumers (Table 2). Further analysis within the group of habitual coffee consumers revealed significant differences on the relative change of physiological measures after the consumption of caffeinated espresso compared to decaffeinated espresso regarding RMSSD = −2.928, P = 0.006), HF (t = −3.588, P= (t (35) (35) 0.001), and LF/HF ratio (t (35) = 2.551, P = 0.015). These differences in RMSSD, HF, and LF/HF ratio were not found in non-habitual consumers, indicating that only habitual coffee consumers showed a relative greater increase in RMSSD and HF, as well a decrease in the LF/HF ratio, following the consumption of caffeinated espresso compared to decaffeinated espresso. Non-habitual coffee consumers showed differences in the BP response to the consumption of caffeinated beverages that were not found in habitual coffee consumers. In non-habitual consumers, the relative change in SBP following the consumption of caffeinated espresso significantly differed from the response following water (t (38) = −4.243, P < 0.0001) or decaffeinated espresso (t (38) = −3.923, P < 0.0001) consumption (Table 2). This pattern was also reflected in PP comparing relative change following the consumption of caffeinated espresso compared to water (t (38) = −2.122, P = 0.040) or decaffeinated espresso (t (38) = −2.335, P = 0.025) consumption. While the consumption of caffeinated espresso resulted in an increase of SBP in non-habitual consumers, it resulted in a decrease in habitual consumers.

Un

co

rre

cte

(all P > 0.05). Descriptive statistics on physiological measures by condition and group are given in Table 2. Repeated-measures ANOVA showed significant main effects of time (2; pre and post) for all parameters (all 0.05) found except for SBP (F = 31.712, P < 0.001), indicating that relative changes on physiological measures did not differ whether participants consumed water, decaffeinated espresso, or caffeinated espresso. The relative decrease in SBP after consumption of water (Δ = −2.24 (3.20)) or decaffeinated espresso (Δ = −2.43 (3.68)) was not found when subjects consumed caffeinated espresso (Δ = −0.45 (4.27)). Paired sample t-test revealed significant differences on relative SBP changes between the caffeinated espresso and decaffeinated espresso condition (t (76) = −3.791, P < 0.0001), as well as the caffeinated espresso and water condition (t (76) = −3.244, P = 0.002). A significant time–condition–group interaction was found for SBP (F = 6.844, P = 0.001), and the LF/HF ratio (F = 3.085, P = 0.049). The relative change in SBP after consuming caffeinated espresso differed significantly between habitual and non-habitual coffee consumers (t (75) = −2.734, P = 0.008). SBP decreased after the consumption of caffeinated espresso in habitual consumers, while it increased in non-habitual consumers (Table 2). The LF/HF ratio revealed significant differences between habitual and non-

4

Nutritional Neuroscience

2015

VOL.

0

NO.

0

Discussion Our results confirmed our hypothesis that consumption of caffeinated espresso would increase

be comparable. Coffee contains many bioactive compounds6 that may interact with caffeine or possess their own pharmacological properties with regard to autonomic effects. Previous studies which investigated effects of coffee preparations on HRV consistently found increases in HF components of HRV compared to decaffeinated coffee in healthy subjects17,18 and patients after myocardial infarction.23 Monda et al. 18 found significant differences only in the supine position, possibly because the sample size was too small to detect differences also in the seated position. The possibility that the observed differences were due to a reduced parasympathetic activation after decaffeinated coffee raises the question whether decaffeinated coffee could even be harmful, at least in habitual consumers with increased cardiovascular risk. Another finding of our study was an inverse SBP response following the consumption of caffeinated espresso in habitual (decrease) versus non-habitual consumers (increase). This observation is in line with previous evidence that the BP effects of caffeine are subject to habituation.11,12 Further, we observed no baseline differences with respect to HRV and BP between habitual and non-habitual coffee consumers on three different days, indicating that regular coffee consumption was not associated with changes in basal vagal activity or BP levels in younger healthy individuals. The observed drop in BP after ingestion of water (or decaffeinated espresso) is likely to be the result of increasing relaxation while the subjects rested. The relatively small amount of consumed fluid (120 ml of warm water) appears to be unlikely to have a substantial impact on sympathetic activation and/or BP. To our knowledge, our study is the first to investigate caffeine effects on vagal activity as indexed by HRV that differentiated between habitual and nonhabitual consumers. Further strengths of our study include the crossover design allowing for minimizing potential confounding by interindividual biological and psychological differences, and the implementation of two control conditions (decaffeinated espresso and water), which allowed controlling for both caffeineindependent effects of espresso as well as the natural course of autonomic parameters during the experiment. On the other hand, our study faces several limitations. First, only younger healthy subjects were studied. Thus, our findings may not be generalizable to older subjects, or subjects with cardiovascular or other diseases. Second, we applied only short-term measurements of cardiovascular parameters of a single dose of espresso or decaffeinated espresso. Therefore, no conclusions with respect to longerterm physiological effects, or the effects of repeated doses can be drawn. Twenty-four-hour measurements

Un

co

rre

cte

parasympathetic activity as indexed by RMSSD and HF power of HRV compared to decaffeinated espresso in habitual consumers. However, the observed increases in RMSSD and HF power of HRV were not significantly larger than those observed in habitual consumers after drinking water, and not significantly larger than those observed in non-habitual coffee consumers after drinking any of the three different beverages. Across subjects and conditions, HRV increased over the course of the experiment, probably due to increasing relaxation while the subjects rested and were allowed to read. Thus, decaffeinated espresso appeared to inhibit vagal activation in habitual coffee consumers. Which mechanisms could explain this unexpected finding? The physiological responses to caffeine include sympathetic activation.7–9 Exposure to caffeine-related stimuli (e.g., smell and taste of decaffeinated coffee) alone was previously shown to also elicit increases in subjective alertness as well as autonomic parameters, for example, electrodermal activity and startle eyeblink reflexes, which were comparable to those after caffeine.34,35 Thus, exposure to conditioned stimuli (consumption of decaffeinated espresso) may elicit a conditioned physiological response, that is, an autonomic activation comparable to that after caffeine consumption.34,35 In the absence of caffeine-induced sympathetic activation, this comparable level of autonomic activation may be achieved by relative vagal withdrawal. This hypothesis may be supported by the finding that the LF/HF ratio, indicating relative sympathetic predominance, increased in habitual consumers, while it decreased in non-habitual consumers. In line with our findings, the recent systematic review by Koenig et al. 16 concluded that the best evidence in their qualitative synthesis was given for an increase in HF components of HRV caused by caffeine or coffee ingestion compared to a control condition. Most studies were carried out in habitual coffee consumers only, and none of the studies had included a control condition which allowed for distinguishing pharmacological effects of caffeine from the natural course of HRV during the experiment. Thus, it is possible that the observed differences between the caffeine and control conditions do not reflect a caffeineinduced activation of parasympathetic activity, but rather an inhibition of parasympathetic activation after placebo administration. Of the studies that compared caffeine (tablets or intravenous application) with placebo in healthy subjects, four studies found a significant increase in HF,17,19,20,36 two studies found no significant differences,21,22 and one study found a decrease in HF.24 Although the majority of studies seem to support our findings, effects of caffeine and coffee may not

Short-term effects of espresso coffee on heart rate variability and blood pressure

dP roo f

Zimmermann-Viehoff et al.

Nutritional Neuroscience

2015

VOL.

0

NO.

0

5

Short-term effects of espresso coffee on heart rate variability and blood pressure

of physiological parameters may be desirable in future studies. Third, subjects were only investigated at rest, and physiological effects of caffeine may be different under physical or psychological stress. In summary, we found no evidence for specific short-term effects of caffeinated espresso on vagal activity in healthy subjects. HRV responses were blunted after consumption of decaffeinated espresso in habitual consumers. This may be explained by an attempt of the organism to establish a sympathovagal equilibrium comparable to that after caffeine consumption.

Acknowledgments We would like to thank all participants, and Mrs Bärbel Girresch for her helpful assistance.

Disclaimer statements Contributors FZV and CH designed the study and wrote the protocol. CH carried out the experiments. FZV wrote the first draft of the manuscript. FZV, CH, JFT, JK, CW, and HCD were involved in the analysis and interpretation of the data, assisted in writing the manuscript, carefully revised the manuscript, and approved its final content. Funding None.

cte

Conflicts of interest None.

rre

Ethics approval The study conformed with guidelines issued in the Declaration of Helsinki, and the Ethics Committee of the Charité University Medical Center Berlin approved the study.

References

Un

co

1 Ding M, Bhupathiraju SN, Chen M, van Dam RM, Hu FB. Caffeinated and decaffeinated coffee consumption and risk of type 2 diabetes: a systematic review and a dose-response metaanalysis. Diabetes Care 2014;37(2):569–86. 2 Ding M, Bhupathiraju SN, Satija A, van Dam RM, Hu FB. Long-term coffee consumption and risk of cardiovascular disease: a systematic review and a dose-response meta-analysis of prospective cohort studies. Circulation 2014;129(6):643–59. 3 Wu JN, Ho SC, Zhou C, Ling WH, Chen WQ, Wang CL, et al. Coffee consumption and risk of coronary heart diseases: a metaanalysis of 21 prospective cohort studies. Int J Cardiol 2009; 137(3):216–25. 4 Je Y, Giovannucci E. Coffee consumption and total mortality: a meta-analysis of twenty prospective cohort studies. Br J Nutr 2014;111(7):1162–73. 5 Malerba S, Turati F, Galeone C, Pelucchi C, Verga F, La Vecchia C, et al. A meta-analysis of prospective studies of coffee consumption and mortality for all causes, cancers and cardiovascular diseases. Eur J Epidemiol 2013;28(7):527–39. 6 Higdon JV, Frei B. Coffee and health: a review of recent human research. Crit Rev Food Sci Nutr 2006;46(2):101–23. 7 Corti R, Binggeli C, Sudano I, Spieker L, Hanseler E, Ruschitzka F, et al. Coffee acutely increases sympathetic nerve activity and blood pressure independently of caffeine content: role of habitual versus nonhabitual drinking. Circulation 2002; 106(23):2935–40. 8 Robertson D, Frolich JC, Carr RK, Watson JT, Hollifield JW, Shand DG, et al. Effects of caffeine on plasma renin activity, catecholamines and blood pressure. N Engl J Med 1978;298(4): 181–6.

6

9 Smits P, Pieters G, Thien T. The role of epinephrine in the circulatory effects of coffee. Clin Pharmacol Ther 1986;40(4):431–7. 10 Myers MG. Effects of caffeine on blood pressure. Arch Intern Med 1988;148(5):1189–93. 11 Ammon HP, Bieck PR, Mandalaz D, Verspohl EJ. Adaptation of blood pressure to continuous heavy coffee drinking in young volunteers. A double-blind crossover study. Br J Clin Pharmacol 1983;15(6):701–6. 12 Casiglia E, Paleari CD, Petucco S, Bongiovi S, Colangeli G, Baccilieri MS, et al. Haemodynamic effects of coffee and purified caffeine in normal volunteers: a placebo-controlled clinical study. J Hum Hypertens 1992;6(2):95–9. 13 Thayer JF, Lane RD. The role of vagal function in the risk for cardiovascular disease and mortality. Biol Psychol 2007;74(2): 224–42. 14 Jarczok MN, Li J, Mauss D, Fischer JE, Thayer JF. Heart rate variability is associated with glycemic status after controlling for components of the metabolic syndrome. Int J Cardiol 2013; 167(3):855–61. 15 Huston JM, Tracey KJ. The pulse of inflammation: heart rate variability, the cholinergic anti-inflammatory pathway and implications for therapy. J Intern Med 2011;269(1):45–53. 16 Koenig JJ, Kuhn W, Morsch K, Schäfer A, Hillecke TK, Thayer JF. Impact of caffeine on heart rate variability: a systematic review. J Caffeine Res 2013;3(1):22–37. 17 Hibino G, Moritani T, Kawada T, Fushiki T. Caffeine enhances modulation of parasympathetic nerve activity in humans: quantification using power spectral analysis. J Nutr 1997;127(7): 1422–7. 18 Monda M, Viggiano A, Vicidomini C, Viggiano A, Iannaccone T, Tafuri D, et al. Espresso coffee increases parasympathetic activity in young, healthy people. Nutr Neurosci 2009;12(1): 43–8. 19 Nishijima Y, Ikeda T, Takamatsu M, Kiso Y, Shibata H, Fushiki T, et al. Influence of caffeine ingestion on autonomic nervous activity during endurance exercise in humans. Eur J Appl Physiol 2002;87(6):475–80. 20 Notarius CF, Floras JS. Caffeine enhances heart rate variability in middle-aged healthy, but not heart failure subjects. J Caffeine Res 2012;2(2):77–82. 21 Richardson T, Rozkovec A, Thomas P, Ryder J, Meckes C, Kerr D. Influence of caffeine on heart rate variability in patients with long-standing type 1 diabetes. Diabetes Care 2004;27(5): 1127–31. 22 Rauh R, Burkert M, Siepmann M, Mueck-Weymann M. Acute effects of caffeine on heart rate variability in habitual caffeine consumers. Clin Physiol Funct Imaging 2006;26(3):163–6. 23 Richardson T, Baker J, Thomas PW, Meckes C, Rozkovec A, Kerr D. Randomized control trial investigating the influence of coffee on heart rate variability in patients with ST-segment elevation myocardial infarction. QJM 2009;102(8):555–61. 24 Sondermeijer HP, van Marle AG, Kamen P, Krum H. Acute effects of caffeine on heart rate variability. Am J Cardiol 2002; 90(8):906–7. 25 McCusker RR, Goldberger BA, Cone EJ. Caffeine content of specialty coffees. J Anal Toxicol 2003;27(7):520–2. 26 Niskanen JP, Tarvainen MP, Ranta-Aho PO, Karjalainen PA. Software for advanced HRV analysis. Comput Methods Programs Biomed 2004;76(1):73–81. 27 Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Heart rate variability: standards of measurement, physiological interpretation and clinical use. Circulation 1996;93(5):1043–65. 28 Buchholz K, Schachinger H, Wagner M, Schorr U, Sharma AM, Deter HC. Enhanced affective startle modulation in salt-sensitive subjects. Hypertension 2001;38(6):1325–9. 29 Sharma AM, Cetto C, Schorr U, Spies KP, Distler A. Renal acid-base excretion in normotensive salt-sensitive humans. Hypertension 1993;22(6):884–90. 30 Sharma AM, Schorr U, Distler A. Insulin resistance in young salt-sensitive normotensive subjects. Hypertension 1993;21(3): 273–9. 31 Zimmermann-Viehoff F, Weber CS, Merswolken M, Rudat M, Deter HC. Low anxiety males display higher degree of salt sensitivity, increased autonomic reactivity, and higher defensiveness. Am J Hypertens 2008;21(12):1292–7. 32 Marks V, Kelly JF. Absorption of caffeine from tea, coffee, and coca cola. Lancet 1973;1(7807):827. 33 Fredholm BB, Battig K, Holmen J, Nehlig A, Zvartau EE. Actions of caffeine in the brain with special reference to

dP roo f

Zimmermann-Viehoff et al.

Nutritional Neuroscience

2015

VOL.

0

NO.

0

Zimmermann-Viehoff et al.

Short-term effects of espresso coffee on heart rate variability and blood pressure

factors that contribute to its widespread use. Pharmacol Rev 1999;51(1):83–133. 34 Mikalsen A, Bertelsen B, Flaten MA. Effects of caffeine, caffeine-associated stimuli, and caffeine-related information on physiological and psychological arousal. Psychopharmacology (Berl) 2001;157(4):373–80.

Un

co

rre

cte

dP roo f

35 Flaten MA, Blumenthal TD. Caffeine-associated stimuli elicit conditioned responses: an experimental model of the placebo effect. Psychopharmacology (Berl) 1999;145(1):105–12. 36 Yeragani VK, Krishnan S, Engels HJ, Gretebeck R. Effects of caffeine on linear and nonlinear measures of heart rate variability before and after exercise. Depress Anxiety 2005;21(3):130–4.

Nutritional Neuroscience

2015

VOL.

0

NO.

0

7

Short-term effects of espresso coffee on heart rate variability and blood pressure in habitual and non-habitual coffee consumers--a randomized crossover study.

Coffee is one of the most widely consumed beverages worldwide. Aim of this study was to investigate short-term effects of espresso coffee on heart rat...
179KB Sizes 3 Downloads 7 Views