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Caffeine and taurine containing energy drink increases left ventricular contractility in healthy volunteers

DOI:10.1007/s10554-014-0577-7
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Jonas Doerner at University of Cologne
Jonas Doerner
Daniel Kuetting at Universitätsklinikum Bonn
Daniel Kuetting
Julian Luetkens at University of Bonn
Julian Luetkens
Claas Philip Nähle at University of Bonn
Claas Philip Nähle
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Abstract

To investigate the impact of a caffeine and taurine containing energy drink (ED) on myocardial contractility in healthy volunteers using cardiac MR and cardiac MR based strain analysis. 32 healthy volunteers (mean age 28 years) were investigated before and 1 h after consumption of a caffeine and taurine containing ED. For assessment of global cardiac functional parameters balanced SSFP-Cine imaging was performed, whereas CSPAMM tagging was used to evaluate global and regional myocardial strain. In addition, ten randomly chosen subjects were investigated once more using a caffeine only protocol to further evaluate the effect of caffeine solely. Heart rate and blood pressure were recorded throughout all studies. ED consumption led to a significant increase in peak systolic strain (PSS) and peak systolic strain rate (PSSR) 1 h after consumption (PSS: w/o ED -22.8 ± 2.1 %; w ED -24.3 ± 2.4 %, P = <0.0001 and PSSR: w/o ED -1.2 ± 0.1 1/s; w ED -1.3 ± 0.2 1/s, P = 0.0056), which was not observed in the caffeine only group. In contrast, global left ventricular function was unchanged (P = 0.2076). No significant changes of vital parameters and diastolic filling pattern were detected 1 h after ED consumption. Consumption of a caffeine and taurine containing ED results in a subtle, but significant increase of myocardial contractility 1 h after consumption.
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1 23
The International Journal of
Cardiovascular Imaging
X-Ray Imaging, Echocardiography,
Nuclear Cardiology Computed
Tomography and Magnetic Resonance
Imaging
ISSN 1569-5794
Int J Cardiovasc Imaging
DOI 10.1007/s10554-014-0577-7
Caffeine and taurine containing energy
drink increases left ventricular contractility
in healthy volunteers
Jonas M.Doerner, Daniel L.Kuetting,
Julian A.Luetkens, Claas P.Naehle,
Darius Dabir, Rami Homsi, Jennifer
Nadal, Hans H.Schild, et al.
1 23
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ORIGINAL PAPER
Caffeine and taurine containing energy drink increases left
ventricular contractility in healthy volunteers
Jonas M. Doerner •Daniel L. Kuetting •Julian A. Luetkens •
Claas P. Naehle •Darius Dabir •Rami Homsi •Jennifer Nadal •
Hans H. Schild •Daniel K. Thomas
Received: 30 June 2014 / Accepted: 19 November 2014
ÓSpringer Science+Business Media Dordrecht 2014
Abstract To investigate the impact of a caffeine and
taurine containing energy drink (ED) on myocardial con-
tractility in healthy volunteers using cardiac MR and car-
diac MR based strain analysis. 32 healthy volunteers (mean
age 28 years) were investigated before and 1 h after con-
sumption of a caffeine and taurine containing ED. For
assessment of global cardiac functional parameters bal-
anced SSFP-Cine imaging was performed, whereas
CSPAMM tagging was used to evaluate global and regio-
nal myocardial strain. In addition, ten randomly chosen
subjects were investigated once more using a caffeine only
protocol to further evaluate the effect of caffeine solely.
Heart rate and blood pressure were recorded throughout all
studies. ED consumption led to a significant increase in
peak systolic strain (PSS) and peak systolic strain rate
(PSSR) 1 h after consumption (PSS: w/o ED -22.8 ±
2.1 %; w ED -24.3 ±2.4 %, P=\0.0001 and PSSR:
w/o ED -1.2 ±0.1 1/s; w ED -1.3 ±0.2 1/s, P=
0.0056), which was not observed in the caffeine only
group. In contrast, global left ventricular function was
unchanged (P=0.2076). No significant changes of vital
parameters and diastolic filling pattern were detected 1 h
after ED consumption. Consumption of a caffeine and
taurine containing ED results in a subtle, but significant
increase of myocardial contractility 1 h after consumption.
Keywords Cardiac magnetic resonance imaging Strain
Myocardial contractility Energy drinks
Introduction
Energy drinks (ED) have become increasingly popular
among adolescents and young adults, especially in college
students, because of an promoted improvement of neuro-
cognitive performance [1] and positive ergogenic effect
[2]. ED usually contain high amounts of caffeine and
taurine as their main pharmacologic ingredients. Some ED
additionally contain supplements such as guarana or crea-
tine. Because the main ingredients i.e. caffeine and taurine
are known to have an impact on the cardiovascular system,
the potential alteration of cardiac function induced by ED
is of special interest. Caffeine has previously been shown
to increase blood pressure and arterial stiffness, as well as
to alter heart rate [3,4]. Taurine (aminoethane sulfonic
acid) is a metabolite of the amino acid cysteine and
therefore a natural body constituent, widely distributed in
humans—especially in the myocardium and skeletal mus-
cles. The pharmacological effects of taurine among others
are membrane stabilization and modulation of calcium
signaling [5–7]. Moreover, in recent studies taurine has
been shown to be essential for cardiac function in a taurine
depleted mouse model [8,9]. To date, there is a lack of data
showing direct in vivo changes of myocardial function
induced by ED.
Cardiac magnetic resonance (MR) based strain imaging
has emerged to be a robust and validated research tool for
the assessment of subtle alterations in global and regional
J. M. Doerner D. L. Kuetting J. A. Luetkens
C. P. Naehle D. Dabir R. Homsi H. H. Schild
D. K. Thomas (&)
Department of Radiology, University of Bonn, Sigmund-Freud-
Str. 25, 53127 Bonn, Germany
e-mail: daniel.thomas@ukb.uni-bonn.de
J. Nadal
Department of Medical Biometry, Informatics, and
Epidemiology, University of Bonn, Sigmund-Freud-Str. 25,
53127 Bonn, Germany
123
Int J Cardiovasc Imaging
DOI 10.1007/s10554-014-0577-7
Author's personal copy
myocardial contractility [10]. Furthermore, cardiac MR is
currently considered as the gold-standard for the assess-
ment of global myocardial function.
The aim of this study was to investigate the impact of a
caffeine and taurine containing ED on myocardial con-
tractility in healthy volunteers using cardiac MR and car-
diac MR based strain analysis.
Methods
Subjects and study design
The study was approved by the ethics committee of the
University of Bonn and conforms to the NIH guidelines for
investigations in humans. All volunteers gave written
informed consent prior to the investigation. Subjects were
screened for heart disease by means of a questionnaire and
ECG. Only healthy volunteers without an apparent medical
history were enrolled. In addition, caffeine and ED habits
were prompted. Exclusion criteria were any contraindica-
tions to MR imaging. Volunteers were instructed to refrain
from consuming caffeine containing drinks as well as
consumption of chocolate for at least 8 h prior to investi-
gation. All investigations were performed in the afternoon
using the same cardiac MR equipment. Volunteers were
investigated before and 1 h after ED consumption. Every
subject consumed a body surface (BSA) indexed amount
(168 ml/m
2
) of the same commercially available caffeine
(0.03 %) and taurine (0.4 %) containing ED outside the
scanner within 5 min subsequent to the baseline MR
examination (see also Fig. 1). BSA was calculated
according to Du Bois [11]. For a typical volunteer this
volume corresponds to a total amount of 105 mg caffeine,
1,304 mg taurine, and a fluid volume of 326 ml. Vital
parameters such as heart rate (HR) as well as systolic blood
pressure (SBP) and diastolic blood pressure (DBP) were
recorded every 5 min throughout the experiment.
From the initial study group, ten volunteers were ran-
domly chosen to serve as a caffeine only (CO) control
group. The subjects were examined using the same imaging
protocol on a different day ([1 week between studies),
however, a commercially available coffee drink containing
34 mg/100 ml caffeine was administered, keeping the total
amount of caffeine identical to the first examination.
Global cardiac function
All cardiac MR studies were performed on a clinical 1.5 T
whole body scanner (Intera, Philips Healthcare, Best, The
Netherlands). Retrospectively gated steady state free pre-
cision (SSFP) cine imaging with 30 cardiac phases per slice
were acquired in the standard cardiac axes [horizontal long
axis (HLA), vertical long axis (VLA), and short axis (SA)].
Scan parameters were as follows: field of view of 370 mm,
a typically time of echo/time of repetition (TE/TR) 1.4/
3.0 ms, slice thickness 8 mm, flip angle 50°, and an in
plane resolution of 1.4 mm. Images were analyzed offline
by one reader (3 years experience in cardiac MR) blinded
to volunteer data including applied study protocol, using
dedicated software (ViewForum, Philips, Best, The Neth-
erlands). Left ventricular (LV) end diastolic volume (LV-
EDV), LV end systolic volume (LV-ESV), LV ejection
fraction (LV-EF), and LV stroke volume (LV-SV) were
calculated. For the ten randomly chosen subjects who
underwent both investigations, early (E) and late (A) dia-
stolic filling rates were derived from the first derivation of
time volume curves and E/A ratios were calculated. This
method has been shown to provide reliable results using a
comparable number of cardiac phases [12].
Strain and torsion analysis
For LV strain and torsion analysis complementary spatial
modulation of magnetization (CSPAMM) tagging sequen-
ces were acquired in basal, midventricular, and apical SA
locations. Sequence parameters were as follows: grid- tag
pattern with a grid-gap of 8 mm; flip angle 25°, time of
echo/time of repetition (TE/TR) 6/33 ms, a field of view of
320 mm and 25 heart phases.
Data were analyzed offline by one reader (3 years
experience in cardiac MR) using harmonic phase-analysis
(Tag Track, GyroTools Ltd., Zurich, Switzerland) [13],
blinded to volunteer data including applied study protocol.
Briefly, a semiautomatic approach was used where epi-
cardial and endocardial track-lines were detected in a phase
with optimal myocardium-blood contrast and manually
adjusted to the anatomical contours. Short axis Lagrangian
circumferential strain (Ecc) values were derived from the
midventricular short axis slice. Rotational indices were
assessed using the apical and basal slices. Intra- and
interobserver variability for the assessment of strain indices
Fig. 1 Illustrating the applied study design. Volunteers were inves-
tigated before and one hour after consumption either of a caffeine and
taurine containing energy drink (ED) or a caffeine control (CO)
containing the same amount of caffeine than the ED. Cardiac MR
cardiac magnetic resonance)
Int J Cardiovasc Imaging
123
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using CSPAMM and HARP analysis has been shown to be
excellent in previous studies [14].
Strain indices
Strain curves and subsequently strain rate curves were
plotted. Peak systolic strain (PSS) was defined as the
maximum value of the global strain in the midventricular
slice. Peak systolic strain rate (PSSR) was defined as the
temporal derivative of strain. Peak diastolic strain rate
(PDSR) was defined as the minimum value of the strain
rate curve [15].
Cardiac MR rotational indices
LV rotation and LV twist were calculated as previously
described [16]. The amount of rotation in degrees for the
basal and apical slice, U, was calculated as the global
rotation in the slice relative to the LV center axis for each
phase. Positive Uindicates a counterclockwise rotation
when viewed from the apex. The global LV twist, H, was
calculated as the mean difference between Uat the apex
and Uat the base (H=U
apex
-U
base
). The peak
untwisting rate was calculated as the largest magnitude of
dH/dtfollowing maximum H. In addition, the circumfer-
ential-longitudinal shear angle (torsion) was calculated
taking cardiac diameter and length into account and thus
allowing for an objective comparison between torsion
values [17].
Statistical analysis
Statistical analysis was performed by the Institute for
Medical Biometry, Information Technology and Epidemi-
ology. All calculations were done using IBM SPSS Statistics
version 22.0. Results are expressed as mean ±SD. Paired
Student‘s ttest was used for comparison of pre- and post-
conditions. A Pvalue lower than 0.05 was considered
significant.
Results
A total of 32 participants (20 male and 12 female) were
investigated. The mean age was 28 ±3.5 years. Mean BSA
was 1.94 m
2
. ED consumption did not result in a significant
change of vital parameters (Table 1a). LV-EDV and LV-SV
increased significantly 1 h after ED consumption, whereas
LV-EF showed no significant change (LV-EDV: w/o ED
130.5 ±26.2 ml; w ED 132.5 ±27.0 ml, P=0.0058; LV-
SV: w/o ED 82.1 ±16.1 ml; w ED 85.0 ±16.6 ml,
P=0.0247; LV-EF: w/o ED 63.1 ±3.9 %; w ED
64.5 ±7.2 %, P=0.2076).
One hour after ED consumption, both systolic strain param-
eters PSS (w/o ED -22.8 ±2.1 %; w ED -24.3 ±2.4 %,
P=\0.0001) and PSSR (w/o ED -1.2 ±0.1 1/s; w ED
-1.3 ±0.2 1/s, P=0.0056) were significantly increased
(representative images and curves are shown in Fig. 2; all strain
and rotational parameters are shown in Fig. 3). Subgroup ana-
lysis revealed that both, men and women responded to ED
regarding PSS, although absolute values differed between gen-
ders for PSS (PSS: male w/o ED -22.2 ±1.7 %; w ED
-23.6 ±2.0 %, P=0.0011; PSS female w/o ED -23.8 ±
2.3 %; w ED -25.4 ±2.7 %, P=0.0039).
PDSR, a parameter for diastolic relaxation showed no
significant change compared to baseline (w/o ED
1.9 ±0.4 1/s; w ED 2.0 ±0.4 1/s, P=0.0772).
Both, systolic and diastolic rotational indices showed no
significant changes post ED consumption or CO con-
sumption compared to baseline (Table 2a).
In the CO group no significant change in HR and SBP was
observed (Table 1b), whereas DBP and mean arterial pres-
sure (MAP) were significantly increased compared to
Table 1 Clinical and global left ventricular parameters for pre and
post condition
Pre ED Post ED Pvalue
(a)
Heart rate (bpm) 64 ±963±9 0.2942
SBP (mmHg) 109 ±10 111 ±9 0.1330
DBP (mmHg) 62 ±863±5 0.3053
MAP (mmHg) 79 ±880±6 0.2102
RPP (bpm*mmHg) 7,107 ±1,397 7,095 ±1,272 0.9308
LV-EDV (ml) 130.5 ±26.2 132.5 ±27 0.0058
LV-SV (ml) 82.1 ±16.1 85.0 ±16.6 0.0247
LV-EF (%) 63.1 ±3.9 64.5 ±7.2 0.2076
E/A 3.3 ±0.9 3.2 ±1.3 0.7678
Pre CO Post CO Pvalue
(b)
Heart rate (bpm) 59 ±461±6 0.1013
SBP (mmHg) 108 ±8 111 ±7 0.1728
DBP (mmHg) 59 ±562±5 0.0184
MAP (mmHg) 77 ±380±4 0.0263
RPP (bpm*mmHg) 6,411 ±599 6,730 ±716 0.1232
LV-EDV (ml) 148.3 ±20.8 146.0 ±20.9 0.0259
LV-SV (ml) 88.4 ±12.4 86.6 ±12.4 0.0920
LV-EF (%) 59.8 ±4.9 59.4 ±3.8 0.4522
E/A 3.2 ±1.0 3.1 ±0.9 0.5543
ED energy drink, CO caffeine only, SBP systolic blood pressure, DBP
diastolic blood pressure, MAP mean arterial pressure, RPP rate
pressure product (HR*SBP), LV-EDV left ventricular end diastolic
volume, LV-SV left ventricular stroke volume, LV-EF left ventricular
ejection fraction, E/A ratio of early and late diastolic filling rate
Int J Cardiovasc Imaging
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baseline (DBP: w/o CO 59 ±5 mmHg; w CO 62 ±
5 mmHg, P=0.0184; MAP: w/o CO 77 ±3 mmHg; w CO
80 ±4 mmHg, P=0.0263).
LV-EDV was significantly decreased (LV-EDV: w/o CO
148.3 ±20.8 ml; w CO 146.0 ±20.9 ml, P=0.0259),
whereas LV-SV and LV-EF showed no significant change
Fig. 2 Representative images and strain curves. aRepresentative
SSFP cine images (left two images) and CSPAMM tagging (right two
pictures) in a short axis plane derived from the same patient in
diastole and systole, respectively. ED energy drink, x-axis in ms of
ECG RR-interval, y-axis dimensionless. bStrain curves from pre
(left) and post (right) energy drink condition showing a higher peak
systolic strain as well as a faster peak systolic strain rate for the post
condition
Fig. 3 Overview of all acquired strain parameters. Significant changes were only found for peak systolic strain and peak systolic strain rate in
the ED group, whereas all other strain parameters revealed no significant differences in both groups. ED energy drink, CO caffeine only
Int J Cardiovasc Imaging
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compared to baseline (LV-SV: w/o CO 88.4 ±12.4 ml; w
CO 86.6 ±12.4 ml, P=0.0920; LV-EF: w/o CO
59.8 ±4.9 %; w CO 59.4 ±3.8 %, P=0.4522).
One hour after CO consumption, both systolic and dia-
stolic strain parameters showed no significant changes
compared to baseline (Table 2b).
Furthermore, E/A ratios did not change significantly,
neither in the ED nor in the CO group (Table 1a, b; rep-
resentative curves are shown in Fig. 4).
Discussion
In this study short-term effects of a caffeine and taurine
containing ED on cardiac function were investigated using
cardiac MR and cardiac MR based strain analysis
(CSPAMM tagging). Cardiac MR tagging has previously
been shown to be capable of detecting subtle changes of
contractility in different pathologies of the heart. Because
of its well-known advantages over other invasive and non-
invasive modalities for measurement of contractility it is
regarded as the ideal tool to monitor contractile changes.
The main finding of this study is a subtle, but significant
increase in LV contractility 1 h after consumption of a
caffeine and taurine containing ED in healthy volunteers.
The main pharmacological components of ED are caf-
feine and taurine, as was the case with the ED used in this
study. Caffeine has several physiological effects such as
relaxation of smooth muscle cells, coronary and cerebral
vasoconstriction, increase of blood pressure, and stimula-
tion of diuresis [3,4]. However, an inotropic effect of
caffeine is still a matter of controversy [18–20].
Taurine is an aminoethane sulfonic acid, which is
molecularly related to the amino acid methionine. It has
several physiological effects, such as conjugation of bile
acids, anti-oxidation, osmoregulation, membrane stabil-
ization, and modulation of calcium signaling. In addition,
taurine is known to increase contractility and shows a
hypotonic effect on blood pressure [5–7].
Baum and Weiss [21] investigated the impact of the ED
Red Bull
TM
(RB) on cardiac parameters before and after
exercise in triathletes . It was found that ingestion of
500 ml RB did not lead to significant changes in HR or
stroke volume within 40 min after consumption under
resting conditions. However, post-exercise recovery
examination detected an increased stroke volume and an
increased LV end diastolic diameter which they related to
increased atrial contractility [21]. In contrast, we found an
increased LV-EDV and unaltered LV-EF resulting in an
increased LV-SV 1 h after ED consumption in a resting
state in healthy volunteers. However, the study by Baum
and Weiss had a methodological limitation in that a
diameter-based approach was used for assessment of car-
diac function, which is faster but less accurate than the
Fig. 4 Representative diastolic filling pattern curves for pre and post
condition. Representative diastolic filling pattern curves derived from
time volume curves of the left ventricle. E is the early filling rate,
which is mostly caused by blood suction after left ventricular
untwisting. A is the late filling rate, which is mostly caused by a
contraction of the left atrium in late diastole. x-axis in ms of the R–R
interval, y-axis dimensionless, Eearly diastolic filling, Elate diastolic
filling, ED energy drink
Table 2 Parameters of regional left ventricular function and strain
indices for pre and post condition
Pre ED Post ED Pvalue
(a)
PSS (%) -22.8 ±2.1 -24.3 ±2.4 \0.0001
PSSR (1/s) -1.2 ±0.1 -1.3 ±0.2 0.0056
PDSR (1/s) 1.9 ±0.4 2.0 ±0.4 0.0772
LV-twist (°) 14.5 ±2.8 15.0 ±3.4 0.2187
LV-torsion (°) 6.4 ±0.9 6.5 ±1.2 0.2604
LV-pUT (°/s) -114.3 ±20.3 -117.7 ±28.3 0.4043
Pre CO Post CO Pvalue
(b)
PSS (%) -23.0 ±2.4 -23.2 ±2.0 0.3978
PSSR (1/s) -1.2 ±0.1 -1.2 ±0.1 0.5912
PDSR (1/s) 1.7 ±0.2 1.8 ±0.2 0.4943
LV-twist (°) 14.9 ±1.8 15.0 ±1.5 0.7762
LV-torsion (°) 6.5 ±1.0 6.5 ±1.2 0.7066
LV-pUT (°/s) -110.0 ±21.4 -107.8 ±21.4 0.5664
ED Energy drink, CO caffeine only, PSS peak systolic strain, PSSR
peak systolic strain rate, PDSR peak diastolic strain rate, LV-twist left
ventricular twist, LV-torsion left ventricular torsion, LV-pUT left
ventricular peak untwist
Int J Cardiovasc Imaging
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volume-based approach employed in this study, which
might explain the different results with respect to LV-EF
and LV-EDV. Furthermore, in the present study cardiac
MR based strain analysis revealed an increased contrac-
tility in the ED group while no significant changes were
observed for E/A ratios. E/A ratios relate to passive filling
during early diastole to active (atrial contraction) filling
during late diastole. Also, no change of diastolic function,
including untwisting, was noted post ED consumption.
Theoretically the observed increase in systolic contractility
could be due to the direct effect of taurine on the myo-
cardium [7], the volume mediated shift of the Frank–
Starling curve (increased filling due to increased atrial
contractility), or both. Because no changes in E/A ratios
were observed in this study, the effect is more likely due to
the direct modulation of contractility of the left ventricle
rather than a shift of the Frank–Starling curve. The direct
effect on LV contractility can be explained by a taurine
related modulation of the activity of Ca
2?
transporters and
the modulation of Ca
2?
sensitivity of the myofibrils [7].
Furthermore, in a taurine depleted mouse model, the lack
of taurine has been shown to result in isolated decreased
fractional shortening, i.e. contractility [8,9]. In this study,
an impact of glucose intake and subsequent insulin excre-
tion on myocardial contractility cannot be ruled out.
However, the normal myocardial function depends mostly
on fatty acid metabolism and less on glucose metabolism.
Also, previous data regarding the inotropic effect of insulin
are controversy [22,23]. Interestingly, 1 h after con-
sumption, the CO group revealed no significant changes of
cardiac function compared to baseline. This leads to the
conclusion that the combination of caffeine and taurine or
taurine itself is responsible for this inotropic effect. Several
studies have demonstrated that the combination of caffeine
and taurine has different effects compared to the single
substances [21,24].
As expected, we observed an increase of diastolic and
MAP in the CO group, as caffeine is known to result in a
peripheral vasoconstriction. However, no change in HR
and only a trend towards an increased blood pressure was
observed in the ED group. This may be explained by the
taurine induced vasodilation and its hypotonic effect [5].
On the other hand a recent study indicated that statistical
significant differences in response to ED may be detected
1 h post consumption at the earliest, reaching peak values
between 80 and 90 min [25]. In our study, the follow-up
period was only 1 h plus scanning time (approximately
75 min), which may explain why statistically significant
differences were not observed for vital parameters.
It is noteworthy that in the subgroup analysis both, men
and women responded to ED with an increased contrac-
tility, although absolute values differed between genders
with higher values in women. Higher standard strain values
in women versus men under resting conditions have pre-
viously been described and are a well-known phenomenon
[26].
First limitation of our study is that it was performed at
rest, therefore it is still unclear how or if ED consumption
has an impact on daily life or athletic performance. Second,
we investigated young and healthy volunteers, therefore
effects to the heart of either younger or older subjects or
patients with medical conditions especially heart disease
are still unknown. Although we performed an intraindi-
vidual comparison, the number of subjects in the control
group (CO) is fairly small, limiting the statistical power of
this sub-analysis. In addition, future studies are needed to
study the clinical relevance of the presumed positive ino-
tropy of taurine. Third, we only investigated short-term
effects to the heart, thus further studies are needed to study
the dose-dependency of cardiac interaction as well as the
long-term impact of ED consumption.
To the best of our knowledge, this is the first study,
which directly showed that consumption of a caffeine and
taurine containing ED increases LV contractility in healthy
volunteers. Based on our findings, the increased left ven-
tricular contractility is most likely caused by a direct
myocardial modulation from one of the ingredients of the
ED. In this context, taurine is the most probable mediator
because of its known influence on myocardial Ca
2?
-
homeostasis and its associated positive inotropic effects.
Conflict of interest None.
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Int J Cardiovasc Imaging
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Author's personal copy
... Most published studies that looked at interactions between taurine and caffeine used CEDs as a comparator (Supplementary File S1). For example, six randomized double-blind control trials compared CEDs to caffeine alone when assessing effects on BP (Brothers et al., 2017, Doerner et al., 2015, Fletcher et al., 2017, Franks et al., 2012, Miles-Chan et al., 2015. One study reported significant SBP and DBP increase (Franks et al., 2012) while another reported significant SBP only (Fletcher et al., 2017) associated with CED intake. ...
... One study reported significant SBP and DBP increase (Franks et al., 2012) while another reported significant SBP only (Fletcher et al., 2017) associated with CED intake. However, the other trials did not observe significant differences between CEDs and caffeine alone groups (Brothers et al., 2017, Doerner et al., 2015, Miles-Chan et al., 2015. A meta analysis summarizing these results suggests these effects are due to caffeine alone (Shah et al., 2016a). ...
... With respect to myocardial performance, several studies which included a caffeine control group (Baum and Weiss, 2001, Doerner et al., 2015, Grasser et al., 2014, reported increased myocardial contractility 1-2 hours after consuming 1-2 servings of CED (average amount in 1 serving equivalent to 105 mg caffeine, 1304 mg taurine; 160 mg caffeine, 2000mg taurine in 2 servings). A double-blind crossover study examined the effect of CEDs on contractile function (stroke volume and fractional shortening) of endurance athletes before and after exercise (Baum and Weiss, 2001). ...
Caffeinated Energy Drinks in the Canadian Context: Health Risk Assessment with a Focus on Cardiovascular Effects
Article
  • May 2021
In Canada, caffeinated energy drinks (CEDs) currently sold under Temporary Marketing Authorizations must meet strict eligibility criteria. These criteria, which include compositional and labelling requirements, were developed based on the outcome of a health risk assessment conducted by Health Canada (HC) in 2013. HC updated its assessment by reviewing new information with the focus on potential cardiovascular effects associated with the consumption of CEDs available for sale in Canada. Due to limited data on CED consumption among Canadians to derive accurate exposure information, the composition of a typical CED was characterized to assess the potential effects of single ingredients and synergistic interactions between ingredients on the cardiovascular system. Surveillance data on potential adverse effects related to CED consumption was also analyzed. After extensive review, HC’s updated assessment confirms the current risk management approach for CEDs is health protective for Canadian consumers, including the potential for cardiovascular effects. The available evidence supports that moderate consumption (up to 500 mL per day) of a typical CED authorized for sale in Canada is safe for the general population of healthy adults and adolescents. It also re-confirms that vulnerable sub-populations (i.e., children, pregnant and/or breastfeeding women, and caffeine-sensitive individuals) should not consume CEDs. Novelty: Consumption up to 500 mL per day of a typical CED is not associated with an increased risk of cardiovascular effects. Children, pregnant and/or breastfeeding women, and caffeine-sensitive individuals should not consume CEDs.
... Another study evaluated cardiac magnetic resonance images of 32 healthy volunteers (mean age 28 years) at baseline and 1 h post-consumption of a caffeine and taurine containing ED. ED consumption led to a significant increase in peak systolic strain rate 1 h after consumption [43]. This was not observed in the caffeine only group. ...
... Also, taurine modulates calcium signaling and toxic levels can affect calcium concentration both intra-and extracellularly [11]. In addition, there is some evidence that taurine may enhance the physiologic actions of caffeine, leading to increased inotropy, and thus may contribute to coronary artery spasm [43,62]. ...
... Caffeine is a competitive antagonist of adenosine receptors A1 and A2A in the central nervous system and myocardium, altering neurotransmitter release and increasing heart rate respectively [8]. Caffeine also induces catecholamine release and causes a rise in intracellular calcium within myocytes [8,43]. Of special relevance, EDs are often consumed in a rapid manner and to excessive amounts, which may predispose to a surge in catecholamines [67]. ...
Cardiovascular Complications of Energy Drinks
Article
Full-text available
  • Jun 2015
... These ingredients account for a manifold of effects [1]. In previous work, Red Bull has been shown to exert cardiovascular effects at rest and during exercise [2][3][4][5][6][7][8][9][10][11]. ...
... These findings are supported by other studies [4,5,11]. Aside of that data two studies reported an unchanged heart rate [8,9]. A larger trial examining 68 young adults at rest demonstrated even a small drop in heart rate [10]. ...
... The researchers of this small-scale study (with 13 subjects) concluded that taurine, either alone or in combination with caffeine, is responsible for this increased contractility of the left atrium [11]. More recently, Doerner and co-workers demonstrated an increased left ventricular contractility assessed by cardiac magnetic resonance in 32 healthy resting volunteers [8]. ...
Red Bull Increases Heart Rate at Near Sea Level and Pulmonary Shunt Fraction at High Altitude in a Porcine Model
Article
Full-text available
  • Jun 2020
Red Bull energy drink is popular among athletes, students and drivers for stimulating effects or enhancing physical performance. In previous work, Red Bull has been shown to exert manifold cardiovascular effects at rest and during exercise. Red Bull with caffeine as the main ingredient increases blood pressure in resting individuals, probably due to an increased release of (nor)-epinephrine. Red Bull has been shown to alter heart rate or leaving it unchanged. Little is known about possible effects of caffeinated energy drinks on pulmonary ventilation/perfusion distribution at sea level or at altitude. Here, we hypothesized a possible alteration of pulmonary blood flow in ambient air and in hypoxia after Red Bull consumption. We subjected eight anesthetized piglets in normoxia (FiO2 = 0.21) and in hypoxia (FiO2 = 0.13), respectively, to 10 mL/kg Red Bull ingestion. Another eight animals served as controls receiving an equivalent amount of saline. In addition to cardiovascular data, ventilation/perfusion distribution of the lung was assessed by using the multiple inert gas elimination technique (MIGET). Heart rate increased in normoxic conditions but was not different from controls in acute short-term hypoxia after oral Red Bull ingestion in piglets. For the first time, we demonstrate an increased fraction of pulmonary shunt with unchanged distribution of pulmonary blood flow after Red Bull administration in acute short-term hypoxia. In summary, these findings do not oppose moderate consumption of caffeinated energy drinks even at altitude at rest and during exercise.
... Intervention studies on young healthy adults showed that ingestion of EDs with absorbed caffeine doses of around 100 mg and below did not result in significant changes in BP (Al-Fares et al., 2015;Alford et al., 2001;Doerner et al., 2015). However, acute 1 ED intakes with absorbed caffeine doses of up to 200 mg typically led to a significant increase in SBP by 3-9 mmHg (Elitok et al., 2015;Franks et al., 2012;Grasser et al., 2014Grasser et al., , 2015Majeed et al., 2017;Miles-Chan et al., 2015;Ragsdale et al., 2010;Steinke et al., 2009) and by 2-5 mmHg in DBP (Elitok et al., 2015;Grasser et al., 2014;Hajsadeghi et al., 2016;Majeed et al., 2017;Miles-Chan et al., 2015;Steinke et al., 2009) compared to baseline. ...
... The identified studies in which ED amounts with no more than 200 mg caffeine were ingested showed an increase in HR (+2 to + 8 bpm, + 16 bpm in connection with sport activity) (Alford et al., 2001;Baum and Weiss, 2001;Elitok et al., 2015;Franks et al., 2012;Grasser et al., 2014Grasser et al., , 2015Steinke et al., 2009), no change (Al-Fares et al., 2015;Doerner et al., 2015;Menci et al., 2013), or a drop in HR (-3 to -5 bpm) (Hajsadeghi et al., 2016;Ragsdale et al., 2010). For ED consumption with ingested caffeine doses of more than 200 mg up to 320 mg, two studies showed an increase in HR (although in one study not significantly (Fletcher et al., 2017)) by approximately + 3 to + 4 bpm (Basrai et al., 2019;Fletcher et al., 2017), while in other studies HR was hardly influenced (Higgins et al., 2017;Kurtz et al., 2013;Phan and Shah, 2014;Rashti et al., 2009;Shah et al., 2016bShah et al., , 2016cSvatikova et al., 2015). ...
... In several identified intervention studies an increased myocardial contractility was observed after ED consumption (Baum and Weiss, 2001;Doerner et al., 2015;Grasser et al., 2014Grasser et al., , 2015Menci et al., 2013;Miles-Chan et al., 2015). ...
Risk assessment of energy drinks with focus on cardiovascular parameters and energy drink consumption in Europe
Article
Full-text available
To assess the possible cardiovascular risks associated with energy drink (ED) consumption in Europe, a comprehensive literature research was performed in regard to (i) possible ED-induced dose-dependent cardiovascular outcomes, (ii) ED consumption patterns in Europe and (iii) the risks of EDs in combination with alcohol. The identified intervention studies primarily investigated acute ED effects in young healthy adults. Moderate consumption of EDs corresponding to an acute caffeine intake of up to 200 mg did not result in clinically relevant cardiovascular changes in young healthy adults. However, high intake of EDs (about 1 L) was associated with moderate to severe adverse effects in some participants (i.a. prolonged QTc interval, palpitations). Studies have indicated that on some occasions, a substantial proportion of ED consuming children and adolescents (12% in 16 EU Member States) drink EDs in high quantities (≥1 L). This could pose a possible health risk to this group since adverse effects by such high ED consumption have been observed already in young healthy adults. Among further measures that might be considered to minimize this identified risk, policy makers could develop information and educational programs with the aim of raising public awareness.
... Interestingly, Greulich et al. showed that two cups of coffee one hour before the examination caused a significant decrease in the ischemic stress, compared to caffeine-naïve adenosine stress cardiac MRI, probably due to coronary hyperemia [72]. The one previous study that analyzed the impact of coffee on cardiac function based on cardiac MRI in 10 subjects found a significant decrease in left ventricular end-diastolic volume but no significant change of left ventricular stroke volume and ejection fraction one hour after coffee consumption, compared to baseline [73]. The apparently differing results of this preliminary study with a small sample size compared to our study might be explained, inter alia, by the fact that they focused on acute effects of coffee consumption, whereas it is most likely that our study looked at long-term effects. ...
Significant Impact of Coffee Consumption on MR-Based Measures of Cardiac Function in a Population-Based Cohort Study without Manifest Cardiovascular Disease
Article
Full-text available
  • Apr 2021
Subclinical effects of coffee consumption (CC) with regard to metabolic, cardiac, and neurological complications were evaluated using a whole-body magnetic resonance imaging (MRI) protocol. A blended approach was used to estimate habitual CC in a population-based study cohort without a history of cardiovascular disease. Associations of CC with MRI markers of gray matter volume, white matter hyperintensities, cerebral microhemorrhages, total and visceral adipose tissue (VAT), hepatic proton density fat fraction, early/late diastolic filling rate, end-diastolic/-systolic and stroke volume, ejection fraction, peak ejection rate, and myocardial mass were evaluated by linear regression. In our analysis with 132 women and 168 men, CC was positively associated with MR-based cardiac function parameters including late diastolic filling rate, stroke volume (p < 0.01 each), and ejection fraction (p < 0.05) when adjusting for age, sex, smoking, hypertension, diabetes, Low-density lipoprotein (LDL), triglycerides, cholesterol, and alcohol consumption. CC was inversely associated with VAT independent of demographic variables and cardiovascular risk factors (p < 0.05), but this association did not remain significant after additional adjustment for alcohol consumption. CC was not significantly associated with potential neurodegeneration. We found a significant positive and independent association between CC and MRI-based systolic and diastolic cardiac function. CC was also inversely associated with VAT but not independent of alcohol consumption.
... 16 A study reported that these energy drinks improved myocardial contractility within one hour of consumption. 17 However, the adverse effects weigh far more than the therapeutic effects of the energy drinks. It was found in a study that students who are on sports drinks have more tendencies towards eating fried and high-sugar foods than those who did not. ...
Relationship of BMI with Junk Food, sleep pattern, exam performance and awareness about its ill health effects in healthy teenagers
Article
Full-text available
Objective: To evaluate the relationship of body mass index of healthy teenagers with junk food, sleep pattern, exam performance and awareness about its ill effects. Methods: The cross-sectional study was conducted from March to June 2017 at University Medical and Dental College, University of Faisalabad, Faisalabad, Pakistan, and comprised subjects aged 13-19. Data was collected using face-to-face interviews, getting the examnation results from respective educational insititutions and calculating the body mass index, Data was analysed using SPSS 22. Results: Of the 226 subjects, 96(42.5%) were boys with a mean age of 15.68 ±1.83 years, and 130(57.5%) were girls with a mean age of 17.00±1.74 years. Based on body mass index, 35(15.5%) subjects were underweight, 88(39%) were normal, 28(12.4%) overweight, 56(24.7%) pre-obese and 19(8.4%) were obese. The independent predictors of body mass index were higher consumption of soft drinks in males and higher consumption of soft drinks and salt in females (p<0.05). Conclusion: Teenagers were found to be well aware of the ill effects of junk food, but they were found to be happy with their dietary habits and unwilling to change it.
... Although isolated caffeinated beverages do not appear to have any significant cardiovascular effect, there was a significant increase in cardiological peak systolic flow after consumption of caffeine and taurine combination 10 . Some studies have shown that taurine and caffeine can interact together to increase cardiac contractility 11 . ...
Evaluation of the effect of energy drink consumption on retina and choroid: An optical coherence tomography and optical coherence tomography angiography study
Article
  • Apr 2020
PURPOSE: Evaluation of retinal and choroidal changes after energy drink consumption by optical coherence tomography and optical coherence tomography angiography. METHODS AND MATERIAL: Forty-two healthy volunteers with neither systemic nor ocular diseases were enrolled in the study. The energy drink (250 ml Red Bull energy drink) was provided to all volunteers. The vascular density of superficial (SCP) and deep capillary plexus (DCP), vascular density in FAZ region, its circumference (PERIM) and vascular density around 300 micron (FD-300), and blood flow in outer retinal and choriocapillaris were measured by OCT-A (AngioVue RTVue XR Avanti (Optovue, Fremont, CA)) before and thirty minutes after consumption of energy drink, in an interval of one hour, 2 hours, 3 hours, 6 hours and 24 hours. Central macular thickness (CMT) was measured by OCT (Heidelberg Engineering, Inc., Heidelberg, Germany), whereas choroid thickness (CT) and retinal nerve fiber layer (RNFL) measurements of the optic nerve were measured by enhanced depth imaging OCT. For control comparison, the same measurements were made after drinking 250 ml of water in the same healthy group. The obtained data were statistically analyzed. RESULTS: Among forty-two volunteers enrolled in study 25 (59,5%) were males and 17 (40,5%) were females, with an average age of 20,58 ± 0,71. The vascular density measurements of parafoveal and perifoveal deep capillary plexus obtained after energy drink consumption were statistically significant. This increase in vascular density of the deep capillary plexus after energy drink consumption seemed to start after half an hour and continued until measurement at 24th hour. On the other hand, the changes in measurements of vascular density from other regions, the blood flows, FAZ, CMT, CT and RNFL values were not statistically significant. In water consumption measurements; despite there was a statistically significant increase in choroidal thickness at 30 minutes and 1 hour (p:0.027, p:0.045, respectively), no significant difference was found in other parameters between consecutive measurements. CONCLUSION: The consumption of energy drinks acutely leads to changes in retinal vascular density parameters.
... Steinke et al. (34) reported a significant increase in HR of 5-7 beats/min within 4 h of administration of an ED. However, other studies have not identified any significant changes in HR (32,35,36,37), or observed a reduction in HR 15 min after consumption of an ED (38). Interestingly, no change was seen in HR or QTc interval 1 h after administration of the single components caffeine (CP + C) or taurine (CP + T). ...
Energy Drinks Induce Acute Cardiovascular and Metabolic Changes Pointing to Potential Risks for Young Adults: A Randomized Controlled Trial
Article
Background: Case reports suggest a link between energy drinks (EDs) and adverse events, including deaths. Objectives: We examined cardiovascular and metabolic effects of EDs and mixtures providing relevant ingredients of EDs compared to a similarly composed control product (CP) without these components. Methods: This randomized, crossover trial comprised 38 adults (19 women, mean BMI 23 kg/m2, mean age 22 y). We examined effects of a single administration of a commercial ED, the CP, and the CP supplemented with major ED-ingredients at the same concentrations as in the ED. The study products were administered at 2 volumes, 750 or 1000 mL. Results: Both volumes of the study products were acceptably tolerated with no dose-dependent effects on blood pressure (BP, primary outcome), heart rate, heart rate corrected duration of QT-segment in electrocardiography (QTc interval), and glucose metabolism. After ED consumption, 11% of the participants reported symptoms, in contrast to 0-3% caused by other study products. After 1 h, administration of an ED caused an increase in systolic BP (116.9 ± 10.4 to 120.7 ± 10.7 mmHg, mean ± SD, P < 0.01) and a QTc prolongation (393.3 ± 20.6 to 400.8 ± 24.1 ms, P < 0.01). Also caffeine, but not taurine or glucuronolactone, caused an increase in BP, but no QTc prolongation. The BP effects were most pronounced after 1 h and returned to normal after a few hours. All study products caused a decrease in serum glucose and an increase in insulin concentrations after 1 h compared to baseline values, corresponding to an elevation in the HOMA-IR (ED + 4.0, other products + 1.0-2.8, all P < 0.001). Conclusion: A single high-volume intake of ED caused adverse changes in BP, QTc, and insulin sensitivity in young, healthy individuals. These effects of EDs cannot be easily attributed to the single components caffeine, taurine, or glucuronolactone. This trial was registered at clinicaltrials.gov as NCT01421979.
... [10][11][12] In adults, caffeine also has haemodynamic effects, including an increase in blood pressure and cardiac contractility. [13,14] Only a few conflicting studies have investigated the cardiovascular effects of caffeine in preterm infants and none were conducted during transition period. A recent study in preterm infants has demonstrated that caffeine administration within minutes of delivery significantly increases the respiratory effort. ...
Haemodynamic effects of prenatal caffeine on the cardiovascular transition in ventilated preterm lambs
Article
Full-text available
Background Caffeine is routinely given to preterm infants hours after birth to treat apnea of prematurity. In view of it’s success, earlier administration in the delivery room is being considered, but little is known about how caffeine may effect the cardiovascular changes during the fetal to neonatal transition. Our aim was to determine the effect of prenatal caffeine administration on haemodynamic parameters in ventilated preterm lambs immediately after birth. Methods Catheters (carotid artery and jugular vein) and ultrasonic flow probes (pulmonary artery and carotid artery) were implanted in preterm lambs (~126 ±2 days of gestation; term is 147 days), immediately before delivery by caesarean section. Before the cord was clamped, lambs were intubated and a caffeine (10mg/kg caffeine-base; n = 9) or saline (n = 5) infusion was given intravenously to the ewe and lamb over a 15-minute period. Two minutes after clamping the cord, ventilation commenced with a sustained inflation (35 cm H2O for 30 seconds) followed by ventilation for 30 minutes (target tidal volume of 6-8ml/kg). Results Blood gas parameters and rectal body temperature were not different between the two groups. Changes in pulmonary blood flow (PBF) and carotid blood flow (CBF) did not differ significantly between groups. PBF increased significantly after ventilation onset in both groups (caffeine p = 0.022, saline p <0.001) and remained elevated thereafter. CBF did not increase but decreased after SI in the caffeine group. Blood pressure, heart rate, and peripheral oxygen saturation did not differ between groups at any stage of the study. Conclusion Prenatal caffeine infusion had no significant effect on acute haemodynamic parameters in ventilated preterm lambs during the cardiorespiratory transition.
The impact of acute energy drink consumption on electrical heart disease: A systematic review and meta-analysis
Article
Aims Energy Drink (ED)-associated cardiovascular emergency visits have increased in recent years. Although a toxicity threshold has been established for caffeine, the safety profile of whole ED consumption has not yet been defined. Methods This systematic review was conducted following the PRISMA guidelines. Three reviewers conducted two separate systematic searches on PubMed on October 24 and December 3, 2019. Out of 250 potential records, 43 prospective clinical studies assessing the effects of ED on heart rate (HR) and/or any electrocardiographic (ECG) parameters were included. A meta-analysis was conducted to estimate pooled p-values using metap command for STATA 10.0. Results After ED consumption, resting HR increased in 71.1% of studies (pooled p-value <0.001) but was only significant in 38%; HR during and after exercise increased in 55.5% (pooled p-value <0.001) and 71.4% of studies, respectively; QRS increased in all but two protocols; evidence on PR interval was contradictory, and corrected QT interval (QTc) increased compared to baseline in all but one study, exceeding the pathological limit value in two of them. T wave changes were seen in two studies, and one study reported a ratio of 5 to 1 in the number of ectopic beats. Conclusion Acute consumption of ED can alter the ECG in certain risk populations, posing a risk whose magnitude is yet to be determined. Caution should be exercised among at-risk and underage individuals but further research in these populations is warranted before restrictions are made.
Cardio- and cerebrovascular responses to the energy drink Red Bull in young adults: a randomized cross-over study
Article
Full-text available
Energy drinks are beverages containing vasoactive metabolites, usually a combination of caffeine, taurine, glucuronolactone and sugars. There are concerns about the safety of energy drinks with some countries banning their sales. We determined the acute effects of a popular energy drink, Red Bull, on cardiovascular and hemodynamic variables, cerebrovascular parameters and microvascular endothelial function. Twenty-five young non-obese and healthy subjects attended two experimental sessions on separate days according to a randomized crossover study design. During each session, primary measurements included beat-to-beat blood pressure measurements, impedance cardiography and transcranial Doppler measurements for at least 20 min baseline and for 2 h following the ingestion of either 355 mL of the energy drink or 355 mL of tap water; the endothelial function test was performed before and two hours after either drink. Unlike the water control load, Red Bull consumption led to increases in both systolic and diastolic blood pressure (p < 0.005), associated with increased heart rate and cardiac output (p < 0.05), with no significant changes in total peripheral resistance and without diminished endothelial response to acetylcholine; consequently, double product (reflecting myocardial load) was increased (p < 0.005). Red Bull consumption also led to increases in cerebrovascular resistance and breathing frequency (p < 0.005), as well as to decreases in cerebral blood flow velocity (p < 0.005) and end-tidal carbon dioxide (p < 0.005). Our results show an overall negative hemodynamic profile in response to ingestion of the energy drink Red Bull, in particular an elevated blood pressure and double product and a lower cerebral blood flow velocity.
Inter-study reproducibility of cardiovascular magnetic resonance tagging
Article
Full-text available
The aim of this study is to determine the test-retest reliability of the measurement of regional myocardial function by cardiovascular magnetic resonance (CMR) tagging using spatial modulation of magnetization. Twenty-five participants underwent CMR tagging twice over 12 ± 7 days. To assess the role of slice orientation on strain measurement, two healthy volunteers had a first exam, followed by image acquisition repeated with slices rotated ±15 degrees out of true short axis, followed by a second exam in the true short axis plane. To assess the role of slice location, two healthy volunteers had whole heart tagging. The harmonic phase (HARP) method was used to analyze the tagged images. Peak midwall circumferential strain (Ecc), radial strain (Err), Lambda 1, Lambda 2, and Angle α were determined in basal, mid and apical slices. LV torsion, systolic and early diastolic circumferential strain and torsion rates were also determined. LV Ecc and torsion had excellent intra-, interobserver, and inter-study intra-class correlation coefficients (ICC range, 0.7 to 0.9). Err, Lambda 1, Lambda 2 and angle had excellent intra- and interobserver ICC than inter-study ICC. Angle had least inter-study reproducibility. Torsion rates had superior intra-, interobserver, and inter-study reproducibility to strain rates. The measurements of LV Ecc were comparable in all three slices with different short axis orientations (standard deviation of mean Ecc was 0.09, 0.18 and 0.16 at basal, mid and apical slices, respectively). The mean difference in LV Ecc between slices was more pronounced in most of the basal slices compared to the rest of the heart. Intraobserver and interobserver reproducibility of all strain and torsion parameters was excellent. Inter-study reproducibility of CMR tagging by SPAMM varied between different parameters as described in the results above and was superior for Ecc and LV torsion. The variation in LV Ecc measurement due to altered slice orientation is negligible compared to the variation due to slice location. Trial registration This trial is registered as NCT00005487 at National Heart, Lung and Blood institute.
The effect of insulin on the heart
Article
Full-text available
  • May 2010
Positive inotropic effects of insulin were described early after the isolation of insulin from the pancreas but data on the effect of insulin on the heart are conflicting. Systemic insulin administration results in a reduction in circulating free fatty acids and an improvement in myocardial glucose uptake, which causes an efficiency improvement in the myocardial cell. There is strong evidence that insulin administration results in functional improvement in dysfunctional myocardium. (Neth Heart J 2010;18:197-201.) Insulin-Heart-Metabolism-Heart Failure-Ventribular Function
Effects of a Caffeine-Containing Energy Drink on Simulated Soccer Performance
Article
Full-text available
To investigate the effects of a caffeine-containing energy drink on soccer performance during a simulated game. A second purpose was to assess the post-exercise urine caffeine concentration derived from the energy drink intake. Nineteen semiprofessional soccer players ingested 630 ± 52 mL of a commercially available energy drink (sugar-free Red Bull®) to provide 3 mg of caffeine per kg of body mass, or a decaffeinated control drink (0 mg/kg). After sixty minutes they performed a 15-s maximal jump test, a repeated sprint test (7 × 30 m; 30 s of active recovery) and played a simulated soccer game. Individual running distance and speed during the game were measured using global positioning satellite (GPS) devices. In comparison to the control drink, the ingestion of the energy drink increased mean jump height in the jump test (34.7 ± 4.7 v 35.8 ± 5.5 cm; P<0.05), mean running speed during the sprint test (25.6 ± 2.1 v 26.3 ± 1.8 km · h(-1); P<0.05) and total distance covered at a speed higher than 13 km · h(-1) during the game (1205 ± 289 v 1436 ± 326 m; P<0.05). In addition, the energy drink increased the number of sprints during the whole game (30 ± 10 v 24 ± 8; P<0.05). Post-exercise urine caffeine concentration was higher after the energy drink than after the control drink (4.1 ± 1.0 v 0.1 ± 0.1 µg · mL(-1); P<0.05). A caffeine-containing energy drink in a dose equivalent to 3 mg/kg increased the ability to repeatedly sprint and the distance covered at high intensity during a simulated soccer game. In addition, the caffeinated energy drink increased jump height which may represent a meaningful improvement for headers or when players are competing for a ball.
Magnetic resonance imaging detects significant sex differences in human myocardial strain
Article
Full-text available
The pathophysiology responsible for the significant outcome disparities between men and women with cardiac disease is largely unknown. Further investigation into basic cardiac physiological differences between the sexes is needed. This study utilized magnetic resonance imaging (MRI)-based multiparametric strain analysis to search for sex-based differences in regional myocardial contractile function. End-systolic strain (circumferential, longitudinal, and radial) was interpolated from MRI-based radiofrequency tissue tagging grid point displacements in each of 60 normal adult volunteers (32 females). The average global left ventricular (LV) strain among normal female volunteers (n = 32) was significantly larger in absolute value (functionally better) than in normal male volunteers (n = 28) in both the circumferential direction (Male/Female = -0.19 ± 0.02 vs. -0.21 ± 0.02; p = 0.025) and longitudinal direction (Male/Female = -0.14 ± 0.03 vs. -0.16 ± 0.02; p = 0.007). The finding of significantly larger circumferential and longitudinal LV strain among normal female volunteers suggests that baseline contractile differences between the sexes may contribute to the well-recognized divergence in cardiovascular disease outcomes. Further work is needed in order to determine the pathologic changes that occur in LV strain between women and men with the onset of cardiovascular disease.
Cardiac and skeletal muscle abnormality in taurine transporter-knockout mice
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Taurine, a sulfur-containing beta-amino acid, is highly contained in heart and skeletal muscle. Taurine has a variety of biological actions, such as ion movement, calcium handling and cytoprotection in the cardiac and skeletal muscles. Meanwhile, taurine deficiency leads various pathologies, including dilated cardiomyopathy, in cat and fox. However, the essential role of taurine depletion on pathogenesis has not been fully clarified. To address the physiological role of taurine in mammalian tissues, taurine transporter-(TauT-) knockout models were recently generated. TauTKO mice exhibited loss of body weight, abnormal cardiac function and the reduced exercise capacity with tissue taurine depletion. In this chapter, we summarize pathological profile and histological feature of heart and skeletal muscle in TauTKO mice.
Physiological roles of taurine in heart and muscle
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Taurine (aminoethane sulfonic acid) is an ubiquitous compound, found in very high concentrations in heart and muscle. Although taurine is classified as an amino acid, it does not participate in peptide bond formation. Nonetheless, the amino group of taurine is involved in a number of important conjugation reactions as well as in the scavenging of hypochlorous acid. Because taurine is a fairly inert compound, it is an ideal modulator of basic processes, such as osmotic pressure, cation homeostasis, enzyme activity, receptor regulation, cell development and cell signalling. The present review discusses several physiological functions of taurine. First, the observation that taurine depletion leads to the development of a cardiomyopathy indicates a role for taurine in the maintenance of normal contractile function. Evidence is provided that this function of taurine is mediated by changes in the activity of key Ca2+ transporters and the modulation Ca2+ sensitivity of the myofibrils. Second, in some species, taurine is an established osmoregulator, however, in mammalian heart the osmoregulatory function of taurine has recently been questioned. Third, taurine functions as an indirect regulator of oxidative stress. Although this action of taurine has been widely discussed, its mechanism of action is unclear. A potential mechanism for the antioxidant activity of taurine is discussed. Fourth, taurine stabilizes membranes through direct interactions with phospholipids. However, its inhibition of the enzyme, phospholipid N-methyltransferase, alters the phosphatidylcholine and phosphatidylethanolamine content of membranes, which in turn affects the function of key proteins within the membrane. Finally, taurine serves as a modulator of protein kinases and phosphatases within the cardiomyocyte. The mechanism of this action has not been studied. Taurine is a chemically simple compound, but it has profound effects on cells. This has led to the suggestion that taurine is an essential or semi-essential nutrient for many mammals.
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Positive inotropic effects of insulin were described early after the isolation of insulin from the pancreas but data on the effect of insulin on the heart are conflicting. Systemic insulin administration results in a reduction in circulating free fatty acids and an improvement in myocardial glucose uptake, which causes an efficiency improvement in the myocardial cell. There is strong evidence that insulin administration results in functional improvement in dysfunctional myocardium. (Neth Heart J 2010;18:197-201.).
The Cardiovascular Effects of Methylxanthines
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In the concentration range that is normally achieved in humans, e.g., after the drinking of coffee or in patients treated with theophylline, the cardiovascular effects of methylxanthines are primarily due to antagonism of adenosine A(1) and A(2) receptors. Inhibition of phosphodiesterases or mobilization of intracellular calcium requires much higher concentrations. In conscious humans, acute exposure to caffeine results in an increase in blood pressure by an increased total peripheral resistance, and a slight decrease in heart rate. This overall hemodynamic response is composed of direct effects of caffeine on vascular tone, on myocardial contractility and conduction, and on the sympathetic nervous system. Caffeine is the most widely consumed methylxanthine, mainly derived from coffee intake. Regular coffee consumption can affect various traditional cardiovascular risk factors, including a slight increase in blood pressure, an increase in plasma cholesterol and homocysteine levels, and a reduced incidence of type 2 diabetes mellitus. Although most prospective studies have not reported an association between coffee consumption and coronary heart disease, these findings do not exclude that the acute hemodynamic and neurohumoral effects of coffee consumption could have an adverse effect in selected patient groups who are more vulnerable for these effects, based on their genetic profile or medication use.
Left Ventricular Torsion. An Expanding Role in the Analysis of Myocardial Dysfunction
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  • Jun 2009
During left ventricular (LV) torsion, the base rotates in an overall clockwise direction and the apex rotates in a counterclockwise direction when viewed from apex to base. LV torsion is followed by rapid untwisting, which contributes to ventricular filling. Because LV torsion is directly related to fiber orientation, it might depict subclinical abnormalities in heart function. Recently, ultrasound speckle tracking was introduced for quantification of LV torsion. This fast, widely available technique may contribute to a more rapid introduction of LV torsion as a clinical tool for detection of myocardial dysfunction. However, knowledge of the exact function and structure of the heart is fundamental for understanding the value of LV torsion. LV torsion has been investigated with different measurement methods during the past 2 decades, using cardiac magnetic resonance as the gold standard. The results obtained over the years are helpful for developing a standardized method to quantify LV torsion and have facilitated the interpretation and value of LV torsion before it can be used as a clinical tool.