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Caffeine and Energy
Jay R. Hoffman, PhD
Department of Health and Exercise Science, The College of New Jersey, Ewing, New Jersey
MENT (41.7% OF THE 403 ATH-
Recent research has indicated
that energy drinks are the most
popular supplement besides
multivitamins in the American adoles-
cent and young adult population
(17,28). More than 30% of all American
male and female adolescents use these
supplements on a regular basis. Energy
drinks are also reported to be the most
popular supplement (41.7% of the 403
athletes surveyed) among young
(17.7 62.0 years) elite British athletes
(40). The primary reason for their use is
thought to be related to a desire for
reducing or controlling body fat
(6,13,17,28). However, many competi-
tive athletes also use these energy
drinks for their potential ergogenic
effect. The basic active ingredient in
these energy drinks is caffeine, and
although ergogenic benefits have been
seen with caffeine supplementation in
doses ranging from 3 to 9 mgkg
(equivalent to approximately 1.5-3.5
cups of automatic drip coffee in a 70-kg
person), there does appear to be
a difference in the ergogenic potential
when caffeine is ingested in a food
source (coffee or sports drink) com-
pared with its anhydrous form.
Although both forms have been shown
to provide an ergogenic effect, the
magnitude of performance improve-
ments appears to be greater when
caffeine is ingested in tablet form
(21). To maximize the effectiveness of
caffeine in an energy drink, supplement
companies will often add several addi-
tional ingredients to exacerbate the
stimulatory potential of caffeine. This
brief review will examine the efficacy of
these energy drinks regarding perfor-
mance improvements and metabolic
enhancement. In addition, issues re-
lating to the safety of energy drink
consumption will also be discussed.
Caffeine alone has been demonstrated
to be effective in enhancing lipolysis,
fat oxidation, and reducing glycogen
breakdown (1,15); however, when it
is combined with other thermogenic
agents, its effectiveness appears to be
magnified (12,27). Caffeine, in combi-
nation with ephedra, has been shown
to be an effective supplement for
increasing metabolic rate and stimulat-
ing fat loss (8,23). However, as a result
of the Federal Drug Administration’s
ban on ephedrine alkaloids in 2004, the
use of alternative therapeutic means
to combat obesity has also been exam-
ined. Synephrine is a mild stimulant
and is thought to contribute to appetite
suppression, increased metabolic rate,
and lipolysis (18). To maximize its
effectiveness as an effective weight loss
supplement, it appears that synephrine
may need to be combined with
other herbal products (26). Some of
these products may include yohimbine,
yerba mate extract, hordenine, phen-
ylethylamine, and methyl tetradecylth-
ioacetic acid. All of which have been
shown to play a role in enhancing
lipolysis and increasing energy expen-
diture (3,5,19). However, many of these
additive ingredients are used for dual
purposes. For instance, phenylethyl-
amine is an endogenous neuroamine
that is often included in weight loss
supplements to enhance mood. Several
studies have shown that phenylethyl-
amine can relieve depression and
improve mood in clinical populations
(24,46). Whether these ingredients
can enhance mood in an apparently
healthy population is not well estab-
lished. A recent examination of an
energy drink containing several ingre-
dients including phenylethylamine was
unable to demonstrate any significant
effect on mood state (32).
A recent study examined the thermo-
genic effect of an acute ingestion of an
energy drink marketed as Redline Prin-
cess (Vital Pharmaceuticals, Inc.,
sports nutrition; supplements; ergogenic
Copyright ÓNational Strength and Conditioning Association Strength and Conditioning Journal | 15
Davie, FL) (32). The supplement con-
tained ahost of ingredients that included
caffeine, beta-alanine, vitamin C, beta-
phenylethylene, hordenine HCL,
evodiamine, N-methyl tyramine, 5-
hydroxytryptophan, potassium citrate,
vinpocetine, yohimbine HCL, and St.
John’s wort extract. Results of the study
indicated that acute ingestion of the
supplement enhanced fat utilization, as
reflected by a greater caloric expenditure
from fat (see Figure 1). Other studies
have shown that an acute ingestion
of a supplement containing caffeine,
citrus aurantium, garcinia cambogia,
and chromium polynicotinate can
significantly increase caloric expendi-
ture (30,49). These multi-ingredient for-
mulations do appear to be effective in
stimulating metabolic changes. The role
thateach ingredient contributesthough is
not well understood. Part of the problem
in understanding individual contribution
of these ingredients is related to the
proprietary nature of the ingredient
panel. To maintain a competitive advan-
tage, sport supplement companies are not
apt to disclose specific ingredient con-
centrations and tend to group various
ingredients as specific ‘‘matrixes.’’
The effect of prolonged consumption
of energy drinks on weight loss has
shown some promising results. In
a clinical examination, Boozer et al.
(8) have reported significant decreases
in body mass and body fat, with
positive alterations to lipid profiles
following 6 months of using an ephed-
rine and caffeine supplement. Providing
further support, an additional study
examining a combination of ephedra,
caffeine, omega-3 fatty acids, and
several vitamins for 9 months in
women showed significant decreases
in body mass, body fat, and improve-
ments in various metabolic indices such
as insulin sensitivity and lipid profiles
(25). The beneficial effect of energy
drinks in short-duration studies and
without the use of ephedra compounds
has also been reported. Roberts and
et al. (44) demonstrated that following
28 days of consuming the energy drink
Celsius (containing 200 mg caffeine,
guarana extract, green tea leaf extract,
glucuronolactone, ginger extract, and
taurine), a significant decrease in body
fat and body mass in healthy college-
aged athletes was seen. These beneficial
effects observed for the multi-ingredient
energy formulations have been dem-
onstrated without concomitant alter-
ations to diet or exercise habits.
Whether the addition of energy drink
consumption to a dietary and exercise
intervention can exacerbate weight and
body fat loss is not well understood. In
consideration of the large obesity
epidemic within the United States
(48), additional research appears war-
ranted to determine whether energy
drinks can play a significant role, in
combination with dietary and exercise
intervention, in the treatment options
associated with weight loss.
Energy drinks are often used by
athletes as a pre-exercise or pre-game
supplement to either enhance the
quality of their workout or improve
athletic performance. Although caf-
feine has been used as an ergogenic
aid for many years, consistent benefits
have only been seen during endurance
activities, in which time to exhaustion
is often reported to increase
(14,20,21,31). This delay in fatigue is
thought to be related to caffeine’s
ability to alter exercise metabolism by
enhancing fat oxidation, thereby pre-
serving muscle glycogen content (47).
Although caffeine has also been sug-
gested to augment strength and power
performance by enhancing muscle
contraction efficiency through acceler-
ated mobilization of intracellular cal-
cium ions from the sarcoplasmic
reticulum (35) and/or by enhancing
glycolytic regulatory enzyme kinetics
(47), evidence demonstrating its ergo-
genic benefit during anaerobic perfor-
mance has been limited.
Figure 1. Average 3-hour caloric expenditure from fat. *Significant difference (p,0.05) between the supplement Redline Princess
and placebo. Data are reported as mean 6SD.
Caffeine and Energy Drinks
To increase the ergogenic potential of
energy drinks, caffeine is often com-
bined with other ingredients to provide
a synergistic effect and increase the
probability of a performance response.
Several recent studies have demon-
strated that a pre-exercise energy
supplement can delay fatigue and
improve the quality of a resistance
training workout (31,33,41). The com-
bination of 450 mg of caffeine, 1,200
mg of garcinia cambogia (50% hydrox-
ycitric acid), 360 mg of citrus auran-
tium extract (6%), and 225 mgof
chromium polynicotinate in an en-
riched coffee drink was shown to
significantly enhance time to exhaus-
tion during cycle ergometer exercise by
29% compared with subjects consum-
ing decaffeinated coffee (31). However,
within the same study, no difference
in anaerobic power performance was
noted between the consumption of
the supplement and placebo (decaf-
feinated coffee). These results were
similar to another study that showed
that an energy supplement (Red Bull
energy drink; Red Bull GmbH, Fuschl
am See, Austria) increased upper-body
muscle endurance but had no effect on
power performance during repeat
Wingate anaerobic power tests (16).
Improvements in the volume of
training (defined as total number of
sets 3repetitions in a workout) from
an energy drink were also confirmed
by a recent study by Hoffman et al.
(33). They showed that an energy
drink containing 110 mg of caffeine,
1,500 mg of L-taurine, 350 mg of
glucuronolactone, and 5.2 g of
branched-chain amino acids consumed
10 minutes before a resistance exercise
session enhanced acute exercise per-
formance by increasing the number of
repetitions and the total volume of
exercise performed during that training
session. The greater volume of training
was also shown to augment both the
growth hormone and the insulin
response to exercise, indicating that
consumption of this pre-exercise en-
ergy supplement enhanced the ana-
bolic response to the training session.
Energy drinks improve endurance per-
formance and the quality of a resistance
exercise workout; however, many ath-
letes use energy drinks primarily for its
stimulatory effect, specifically to en-
hance focus, alertness, and reaction time.
The datato support this effectare limited
but they do provide evidence to support
many of these empirical claims made by
athletes. The popular energy drink Red
Bull has been shown to enhance cogni-
tive performance through improved
choice reaction time, concentration,
and memory, which reflected an im-
proved alertness (2). Recently, Hoffman
et al. (29) examining an energy drink
containing caffeine and a number of
additional herbal and botanical com-
pounds that included evodiamine,
N-acetyl-L-tyrosine, hordenine, 5-
hydroxytryptophan, potassium citrate,
N-methyl tyramine, sulbutiamine, vin-
pocetine, yohimbine HCL, and St.
John’s wort extract (marketed as Redline
Extreme; Vital Pharmaceuticals, Inc.,
Davie, FL) reported significant increases
in focus, alertness, and reaction time.
Improvements in reaction time (see
Figure 2) were assessed through both
visual and auditory stimuli. Interestingly,
despite a significant improvement in
reaction ability, no significant improve-
ments were noted in anaerobic power
performance as assessed by repeated
Wingate anaerobic power tests.
As mentioned earlier, caffeine is a mild
stimulant and is commonly found in
coffee, tea, chocolate, and soft drinks.
The concentration of caffeine in these
products has been reported to range
from 40 to 150 mg (37). In contrast, the
top selling energy drinks have caffeine
levels that range from 75 to 174 mg per
Figure 2. Reaction time: Average percentage of successful hits from total possible targets.*Significant difference (p,0.05) between
the supplement Redline Extreme and placebo. Data are reported as mean 6SD.
Strength and Conditioning Journal | 17
serving, while in some of the higher
caffeine energy drinks, levels may
exceed 500 mg per serving (42). The
adverse effects seen with caffeine in
these doses include insomnia, nervous-
ness, headache, and tachycardia (9).
However, changes in the blood pres-
sure response have been inconclusive.
Several studies have reported signifi-
cant elevations in systolic blood pres-
sure (30,49), while others have shown
no change (2,10,32,45). Differences
between the studies are not clear, but
they are likely related to differences
within the combination of ingredients
that are generally associated with these
energy drinks. These studies have
consistently shown no alterations in
diastolic blood pressure. Interestingly,
a recent discussion of the safety issues
associated with energy drinks sug-
gested that the products that are
generally added to these supplements
such as guarana, ginseng, and tuarine
are in concentrations that are far below
the amounts associated with adverse
events (9). However, in energy drinks
that contain ephedra alkaloids or other
b-agonists such as citrus aurantium
(e.g., synephrine), a higher risk for an
exaggerated sympathetic response may
be present.
Several case reports have indicated
that energy drinks may increase the
risk for ventricular tachycardia (38) or
myocardial ischemia (7). However, a
European study has reported no asso-
ciation between caffeine consumption
and cardiac conduction abnormalities
(36). A health concern though has
been raised if energy drinks are con-
sumed with alcohol. A recent study has
reported a blunted cardiac autonomic
control in healthy subjects consuming
energy drinks mixed with alcohol (50).
Although no significant arrhythmias
were reported, the authors suggested
that individuals who were predisposed
to arrhythmia may be at an increased
risk for a significant adverse event if
they combine alcohol with an energy
A concern that energy drinks can
increase the risk for dehydration was
raised based on evidence that caffeine
can induce diuresis and natriuresis (43).
However, in several well-designed
studies, caffeine consumption has not
been shown to impair hydration,
exacerbate dehydration, or impair
thermoregulation (11,22). In a recent
review of the literature, Armstrong
et al. (4) have surmised that caffeine
does not reduce exercise-heat toler-
ance or increase the risk for hyperther-
mia. However, it should be
acknowledged that energy drinks that
contain ephedra or other b-agonistic
compounds may not have the same
benign risk. Several well-documented
heat deaths of professional athletes
who were using ephedra had resulted
in part to the banning of that herbal
ingredient in 2004. It may be prudent
to advise against the use of energy
drinks that contain these ingredients
in individuals who are poorly condi-
tioned, overweight, and exercising in
the heat.
Additional concerns recently raised
about energy drinks surround the
issues relating to dependence, with-
drawal, and tolerance (42). Although
many of these issues have been studied
with caffeine, direct studies with en-
ergy drink consumption are limited.
There is considerable debate whether
caffeine can produce a dependence
syndrome that is similar to that
associated with a narcotic. A few
studies have suggested that habitual
caffeine users may fulfill diagnostic
criteria for substance dependence
(34,39); however, there is no evidence
to suggest such behaviors in individuals
consuming energy drinks. The issue
of withdrawal has been noted in more
than 60 studies published in the
medical literature in the past 10 years
(42). Symptoms such as headache,
tiredness/fatigue, sleepiness, and irri-
tability are associated with caffeine
withdrawal. How this is affected by
energy drink consumption is also not
well understood. The issue of tolerance
is a major concern for athletes who use
energy drinks on a regular basis during
their competitive season. In athletes
who play on a daily basis such as in
baseball, the issue of tolerance may
have important implications as the
season progresses. Although high
caffeine ingestion has been associated
with tolerance (42), there are no
studies to date that have examined
the issue of tolerance in energy drinks.
Energy drinks are the most popular
supplement being used by young adult
and athletic populations today.
Although caffeine is the primary active
ingredient in these drinks, the combi-
nation of various other ingredients
including herbal and botanical com-
pounds makes it quite difficult to
provide a general statement of effi-
ciency for energy drinks. The answer
regarding the efficacy and risk associ-
ated with an energy drink is specific to
the ingredients within each respective
supplement. Based on a number of
studies examining various energy drink
formulations, the efficacy of these
supplements has been established
regarding improvements in exercise
endurance (e.g., delaying fatigue).
However, ingestion of energy drinks
does not appear to provide any
significant effect on strength and
power performance but does appear
to enhance the quality of a resistance
training workout. In addition, many
strength/power athletes use energy
drinks for their stimulatory potential.
Ingestion of these drinks has been
shown to enhance alertness, focus,
and reaction time to various stimuli.
Energy drinks have also been shown to
increase energy expenditure and
enhance fat utilization. Several studies
of various durations have provided
interesting evidence, suggesting that
energy drinks may have a role in
weight loss regimens and may provide
a potential therapeutic effect when
combined with dietary and exercise
interventions. However, additional
research is still warranted in this area.
The majority of energy drinks appear
to be well tolerated with minimal risks
associated with their use. However,
energy drinks containing ephedra
alkaloids or other b-agonists may
increase the sympathetic response
Caffeine and Energy Drinks
(i.e., elevations in heart rate and blood
pressure) that can potentially exacer-
bate an underlying cardiovascular
problem. Interestingly, there are a num-
ber of well-controlled clinical studies
that showed that a low-dose ephedra/
caffeine combination can significantly
alter body composition. With appro-
priate medical supervision, the use of
such energy drink combinations may
prove to be beneficial. Regardless,
prudence should be used in the use
of these supplements for individuals
who are untrained, over fat, and
exercising in the heat.
Jay Hoffman is
a professor and
chair of the
Department of
Health and Exer-
cise Science at The
College of New
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Caffeine and Energy Drinks
... Energy drinks (EDs) have been available at the global market for almost 100 years and today, they are advertised as 'tools' boost energy, enhance physical performance and mental alertness. According to several reports, EDs are one of the most popular supplement commodities in the United States second only multivitamins (Froiland et al. 2004;Hoffman 2010;Campbell et al. 2013). EDs have not only appealed to the adult population but to children and adolescents too, as we have seen an increase in the consumption rate within these population groups. ...
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Energy drinks (EDs) have been available at the global market for almost 100 years and today, they are advertised as ’tools’ boost energy, enhance physical performance and mental alertness. Some of the main chemical components in EDs include caffeine, ginseng, and taurine. The market and consumption of these beverages is growing exponentially, and this is becoming a public health problem due to the adverse effects associated with these drinks. The main objective of this article is to review important ingredients in popular EDs in South Africa and look at their molecular mechanisms of action and interaction with other compounds within the body. At the same time, the authors aim to review the global consumption pattern of EDs among children and adolescents. Finally, this review article will provide an overview the health risks associated with EDs consumption. A literature review was conducted using scholarly databases. Keywords such as energy drinks, adverse effects, advertising, alcohol, caffeine, taurine, and regulations were used. Despite the claims of having significant benefits to mental and physical stamina, long-term consumption of EDs could have detrimental public health implications; and could result in increasing rates of the central nervous system disorders and the cardiovascular complications. A knowledge gap exists on how the lack of education impacts the decision of consumers of EDs and the parental guidance provided to children and adolescents in relation to the consumption of these beverages in South Africa. To address the issue of excessive ED consumption, communities need to be made aware of the harmful effects of these beverages through health education and implementing strict regulatory measures through policy.
... A lot of placebo-controlled crossover studies have showed the efficacy of EDs as contributing factors to mental function and physical performance [17,18]. Several studies have found that EDs improve endurance, although this effect can be attributed to caffeine or carbohydrates [19]. ...
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The energy drinks are beverages that contain caffeine and are consumed by students, children, adolescents and young adults to enhance their athletic and cognitive performance. Significant adverse effects have been reported. They vary from mild symptoms to death. The present study attempts to assess the risk of using energy drinks by exercisers and athletes. In order to achieve this, we evaluate the consumption and knowledge level of the consumers. The lack of awareness can lead to dangerous practices. Views on appropriate public health protection measures are also being investigated. The grade of consumption (35.5%) is within the bounds of the literature. The main source of knowledge is the advertisement (69.2%), which does not guarantee objective information. Therefore, although exercisers and athletes believe that they have adequate knowledge on the subject (91.2%), in fact this is not the case (the knowledge score is 10.12/18). Thus, half of them consume concurrently energy drinks with alcohol (a perilous practice). The study emphasizes the need of taking measures for public health protection.
... The primary purpose of energy drinks (EDs) and sports drinks is to enhance the body energy during sports, exercises, and other athletic activities (Raizel et al., 2019;Sankararaman et al., 2018). The literature shows their therapeutic potential and enhanced performance on caffeine content intake (Hoffman JR, 2010). Some investigations have framed with caffeinated EDs to show the effects. ...
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Objective: In the present society, the energy drinks (EDs) are used by general public and mainly by the sports persons. Though the caffeine content of EDs is creating health consequences on excess consumption, the present study targets their health benefits on central nervous system (CNS) focusing antidepressant and cognitive potentiality. The most typically used EDs have been selected for the study such as Red Bull, Monster and Enerzal for the present research. Methodology: The study started with in-silico studies to get information about the neurological receptor binding of the major and common chemical components of the EDs. The antidepressant study of energy drinks was carried out following FST (Forced Swim Test) and TST (Tail suspension test) methods. Their cognition effect was assessed by using Y-maze apparatus. Further, their mechanism of action was evaluated by estimating their effect on brain dopamine and serotonin level. Results: In-silico study revealed the enhanced agonistic binding of the major common components of the EDs to D2 and serotonin receptors. Further their significant (p<0.001) antidepressant property was estimated both in tail suspension and forced swim tests along with significant cognitive property.
... Caffeinated energy drinks are very common in sports, with a commonness of 73 percent in American college athletes [8], 75 percent in Canadian Varsity athletes [9], and 42 percent in British elite athletes [10]. Caffeine's pervasive usage in athletics is probably a combination of social and physiological factors: caffeine and caffeinated drinks are cheap, and their consumption is frequently related to social behaviors. ...
Objectives To examine the efficacy of caffeine on athletic performance, also to establish the most effective dose and form of caffeine intake that is needed to bring about a positive effect in performance. News Studies were searched in various electronic databases, including Web of Science, PubMed, Pedro, and CINAHL. Studies were excluded if: 1) it was conducted before January 2010; 2) caffeine was given along with other substance/exercise; 3) only abstract was available; 4) it included non-healthy athlete; 5) the population was not involved in any kind of sports; 6) Pedro score < 7. Thirty articles were included in this review after the removal of duplicates and applying exclusion criteria. A random-effect model was used in this meta-analysis to analyze the effect of caffeine on athletic performance using the standardized mean difference with a 95% confidence interval. Our meta-analysis showed that there is a significant effect, immediately (SMD: 0.82; 95% confidence interval: 0.27, 1.37; P = 0.003) and after 60 minutes (SMD: 0.26; 95% confidence interval: 0.05, 0.47; P = 0.02) of caffeine intake on jump height favouring the placebo group. There was a significant effect on reaction time (SMD: −0.40; 95% confidence interval: −0.76, −0.04; P = 0.03) and agility (SMD: −0.36; 95% confidence interval: −0.66, −0.07; P = 0.02) after 60 minutes of caffeine intake favouring the experimental group. Prospects and projects To back up the results presented in this study, more research into the effects of caffeine supplementation on non-athlete performance is required. Conclusion Caffeine supplementation is efficient in improving the reaction time and agility of an athlete. Agility and reaction time is seen to improve when an athlete is supplemented with caffeine at a dosage of 3 mg/kg of body mass and 6 mg/kg of body mass, respectively. Also, improvement in agility and reaction time favoring caffeine-supplemented group occurs after 60 minutes of caffeine ingestion.
... Furthermore, a previous investigation has suggested a synergetic interaction between ED ingredients, with greater performance benefits achieved by the whole beverage, with neither CAF nor GLU in isolation resulting in performance benefits. 6 It is common for athletes to consume ED prior to competition, 7 yet the efficacy of the functional ingredients contained in these drinks remains to be determined. It is unresolved whether the ED Red Bull® or its functional ingredients improve performance in short duration high intensity middle distance endurance events such as a 5-km race. 2 With close to 8 million people completing a 5-km event in the United States in 2015, 8 identifying the most appropriate pre-exercise dietary supplement to improve exercise performance is merited particularly when it is very challenging to consume appropriate amounts of supplements during running events that last 30 mins or less. ...
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Introduction: The purpose of this study was to evaluate the independent and combined effects of energy drink (ED) functional ingredients, caffeine (CAF), taurine (TAU), and glucose (GLU) on 5-km running time trial (5KTT) performance in recreational endurance runners. Methods: Twenty recreational endurance runners (10 men, 10 women, 21.3 ± 2.2 years) participated in a double blind, placebo controlled, repeated measures study. In the first session subjects completed the 5KTT without consuming a drink (control trial-CON). Subjects were then randomly assigned to supplement with 500 ml of a commercially available ED, CAF (160 mg), TAU (2g) and GLU (54g) 60 minutes before completing a 5KTT on a treadmill; separated by seven days. Time, heart rate, RPE, and affect were recorded at 500-m intervals during the time trial (TT). Session RPE and session Affect were obtained post TT. Results: TT performance did not differ across conditions (CON: p = .80). HR and RPE increased wile affect decreased during the TT, irrespective of the substance ingested (all p > 0.05). Session RPE was significantly higher in the ED trial (8.1 ± 1.1) compared to GLU (7.7 ± 1.2), TAU (7.5 ± 1.3) and CON (7.5 ± 1.3) but not CAF (7.8 ± 1.3) (p = 0.025). Conclusions: The present data does not unequivocally support an ergogenic potential of a popular ED above that of CAF, TAU, and GLU, if consumed sixty minutes before exercise in men and women recreational distance runners.
Despite emerging evidence about the influence of energy drinks on the quality of athletes' performance, there is little information about their effects on exercise-induced damage markers after long-term activities. This study aimed to investigate the acute effects of hype energy drink (HED) to ameliorate liver and muscle damage enzymes, and cardiovascular indices-induced by a soccer match. A total of 22 elite male soccer players (age 20.36 ± 1.91) were recruited. Participants performed two experimental conditions, separated by a 14-day washout period. They consumed 2 × 250 ml of HED or placebo for 5 d before the soccer match, on match day, and for 1-day post- match. Measurements of muscle (CK and LDH), and liver (ALT, AST, and ALP) damage indices, and blood pressure (BP) parameters were taken at baseline, pre- match, post- match, and 24 h post- match. The results showed that the levels of ALT, AST, ALP, CPK, and LDH enzymes significantly decreased in HED condition from pre- match to 24 h post- match, compared with placebo (p<0.001). Also, consumption of energy drinks reduced systolic, diastolic, and mean BP. In conclusion, elevated serum levels of muscle and liver damage enzymes, and higher values of BP indices are improved 24 hours after soccer match following HED ingestion, compared to placebo. Therefore, it seems that consuming HED can lead to faster recovery of muscle and liver damage and improve recovery in soccer players.
Poor eating and drinking habits and physical inactivity have contributed to the prevalence of chronic diseases in the USA such as obesity, diabetes, hypertension, and cardiovascular disease. These conditions are preventable by integrating healthy eating and drinking habits into daily life. Strategies for healthy eating such as volumetrics, mindful eating, and intuitive eating assist individuals in controlling their daily intake foods and beverages while supporting healthy food choices. There are also several resources available for the consumer to encourage healthy eating. One resource is the Dietary Guidelines for Americans, which provides scientific, evidence-based food and beverage recommendations for toddlers through the elder years. The Guidelines aim to promote health, prevent chronic disease, and help people reach and maintain a healthy weight. The purpose of this chapter is: (1) to address the role of the registered dietitian as the food and nutrition expert who can assist individuals in integrating healthy eating and drinking practices in their lifestyle; (2) to review strategies for healthy eating such as volumetrics, mindful eating, and intuitive eating; (3) to discuss the resources and tools for healthy eating such as the 2015–2020 Dietary Guidelines for Americans; (4) to review the beverages that consumers choose on a daily basis; and (5) to present reliable information on the Internet, social media, apps, and blogs about healthy dietary and fitness practices for consumers.
KEYPOINTS • la storia del doping, dalle sue origini fino alle recenti forme di contrasto come la creazione dell’Agenzia Mondiale Anti-doping (WADA) e della legge penale italiana in materia (n° 376/2000). • Le sostanze di abuso più comuni che si utilizzano in ambito sportivo attraverso una panoramica degli studi scientifici più importanti mostrandone sia i benefici sia i rischi legati all’assunzione. Tra queste: -L’amfetamina (proibita durante le competizioni); -La cocaina (proibita durante le competizioni); -La caffeina (monitorata ma non proibita); -La nicotina (monitorata ma non proibita); -La cannabis (proibita durante le competizioni); -L’alcol (non proibito).
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The thermogenic effect of a high energy supplement was examined in ten healthy and physically active female subjects that underwent two testing sessions administered in a randomized and double-blind fashion. The subjects reported to the Human Performance Laboratory after at least a 3-hour post-absorptive state and were provided either 120 ml of the supplement (SUP), or 120 ml of a placebo (PL). Following ingestion the subjects rested in a semi-recumbent position for 3 hours. The area under the curve analysis revealed no difference in oxygen consumption between SUP and PL for the 3 hours study period. No difference in en-ergy expenditure was seen between SUP (.92±.16 kcal·min -1) and PL (.89±.17 kcal·min -1). A signifi cant dif-ference in the utilization of stored fat as an energy source was seen between the groups during the 3 hours study (.42±.18 kcal·min -1 and .24±.10 kcal·min -1 in SUP and PL, respectively). These differences were seen in the fi rst (.35 ±.19 kcal·min -1 and .20±.13 kcal·min -1 in SUP and PL, respectively) and second hour (.46±.21 kcal·min -1 and .24±.11 kcal·min -1 in SUP and PL, respectively), but not in the third hour (.47±.25 kcal·min -1 and .33±.20 kcal·min -1 in SUP and PL, respectively). No differences in heart rate, blood pressure or mood were seen between the groups. The results indicate that although acute ingestion of this supplement does not increase energy expenditure, it does appear to stimulate a signifi cant increase in fat utilization.
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Abstract The purpose of this study was to examine the effects of ingesting JavaFit™ Energy Extreme (JEE) on aerobic and anaerobic performance measures in recreationally-active male and female coffee drinkers. Five male (27.6 ± 4.2 yrs, 93.2 ± 11.7 kg, 181.6 ± 6.9 cm) and five female (29 ± 4.6 yrs, 61.5 ± 9.2 kg, 167.6 ± 6.9 cm) regular coffee drinkers (i.e., 223.9 ± 62.7 mg·d<sup>-1 </sup>of caffeine) participated in this study. In a cross-over, randomized design, participants performed a baseline (BASELINE) graded treadmill test (GXT) for peak VO<sub>2 </sub>assessment and a Wingate test for peak power. Approximately 3–4 d following BASELINE testing, participants returned to the lab for the first trial and ingested 354 ml of either JEE or decaffeinated coffee (DECAF), after which they performed a GXT and Wingate test. Criterion measures during the GXT included an assessment of peakVO<sub>2 </sub>at maximal exercise, as well as VO<sub>2 </sub>at 3 minutes and 10 minutes post-exercise. Additionally, time-to-exhaustion (TTE), maximal RPE, mean heart rate (HR), mean systolic pressure (SBP), and mean diastolic blood pressure (DBP) were measured during each condition. Criterion measures for the Wingate included mean HR, SBP, DBP, peak power, and time to peak power (TTP). Participants then returned to the lab approximately one week later to perform the second trial under the same conditions as the first, except consuming the remaining coffee. Data were analyzed using a one way ANOVA (p < 0.05). Our results indicate that JEE significantly increased VO<sub>2 </sub>at 3 minutes post-exercise when compared to BASELINE (p = 0.04) and DECAF (p = 0.02) values, which may be beneficial in enhancing post-exercise fat metabolism.
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Background The purpose of this study was to examine the effects of a functional coffee beverage containing additional caffeine, green tea extracts, niacin and garcinia cambogia to regular coffee to determine the effects on resting energy expenditure (REE) and hemodynamic variables. Methods Subjects included five male (26 ± 2.1 y, 97.16 ± 10.05 kg, 183.89 ± 6.60 cm) and five female (28.8 ± 5.3 y, 142.2 ± 12.6 lbs) regular coffee drinkers. Subjects fasted for 10 hours and were assessed for 1 hour prior (PRE) and 3 hours following 1.5 cups of coffee ingestion [JavaFit™ Energy Extreme (JF) ~400 mg total caffeine; Folgers (F) ~200 mg total caffeine] in a double-blind, crossover design. REE, resting heart rate (RHR), and systolic (SBP) and diastolic (DBP) blood pressure was assessed at PRE and 1, 2, and 3-hours post coffee ingestion. Data were analyzed by three-factor repeated measures ANOVA (p < 0.05). Results JF trial resulted in a significant main effect for REE (p < 0.01), SBP (p < 0.01), RER (p < 0.01), and VO2 (p < 0.01) compared to F, with no difference between trials on the RHR and DBP variables. A significant interaction for trial and time point (p < 0.05) was observed for the variable REE. The JF trial resulted in a significant overall mean increase in REE of 14.4% (males = 12.1%, females = 17.9%) over the observation period (p < 0.05), while the F trial produced an overall decrease in REE of 5.7%. SBP was significantly higher in the JF trial; however, there was no significant increase from PRE to 3-hours post. Conclusion Results from this study suggest that JavaFit™ Energy Extreme coffee is more effective than Folgers regular caffeinated coffee at increasing REE in regular coffee drinkers for up to 3 hours following ingestion without any adverse hemodynamic effects.
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The purpose of this study was to examine the effect of a pre-exercise high energy drink on reaction time and anaerobic power in competitive strength/power athletes. In addition, the effect of the pre-exercise drink on subjective feelings of energy, fatigue, alertness and focus was also explored. Twelve male strength/power athletes (21.1 +/- 1.3 y; 179.8 +/- 7.1 cm; 88.6 +/- 12.1 kg; 17.6 +/- 3.3% body fat) underwent two testing sessions administered in a randomized and double-blind fashion. During each session, subjects reported to the Human Performance Laboratory and were provided with either 120 ml of a high energy drink (SUP), commercially marketed as Redline Extreme(R) or 120 ml of a placebo (PL) that was similar in taste and appearance but contained no active ingredients. Following consumption of the supplement or placebo subjects rested quietly for 10-minutes prior to completing a survey and commencing exercise. The survey consisted of 4 questions asking each subject to describe their feelings of energy, fatigue, alertness and focus for that moment. Following the completion of the questionnaire subjects performed a 2-minute quickness and reaction test on the Makoto testing device (Makoto USA, Centennial CO) and a 20-second Wingate Anaerobic Power test. Following a 10-minute rest subjects repeated the testing sequence and after a similar rest period a third and final testing sequence was performed. The Makoto testing device consisted of subjects reacting to both a visual and auditory stimulus and striking one out of 30 potential targets on three towers. Significant difference in reaction performance was seen between SUP and PL in both average number of targets struck (55.8 +/- 7.4 versus 51.9 +/- 7.4, respectively) and percent of targets struck (71.9 +/- 10.5% versus 66.8 +/- 10.9%, respectively). No significant differences between trials were seen in any anaerobic power measure. Subjective feelings of energy (3.5 +/- 0.5 versus 3.1 +/- 0.5) and focus (3.8 +/- 0.5 versus 3.3 +/- 0.7) were significantly higher during SUP compared to PL, respectively. In addition, a trend towards an increase in average alertness (p = 0.06) was seen in SUP compared to P. Results indicate a significant increase in reaction performance, with no effect on anaerobic power performance. In addition, ingestion of this supplement significantly improves subjective feelings of focus and energy in male strength/power athletes.
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The objective was to study nutritional supplement use among young elite UK athletes to establish whether a rationale versus practice incongruence exists, and to investigate the sources of information. Survey data were analysed for association between supplements used and motives for using such substances among young athletes along with the sources of advice and literature precedents on supplement effects. Participants were elite UK male and female athletes, within the age range between 12 and 21 (n = 403), mean age 17.66 +/- 1.99. Associations between type of supplements and reasons for using supplements were tested by calculating Pearson's chi2 and the strength of these symmetric associations shown by phi association coefficients. Single supplement use was reported by 48.1%, with energy drinks being the most popular, consumed by 41.7% of all athletes and 86.6% of the supplement users in the sample. No agreement was observed between athletes' rationale and behaviour in relation to nutritional supplements except for creatine. Among health professionals, nutritionists and physiotherapists, followed by coaches, were most frequently consulted. Answers regarding reasons and supplements used showed incongruence and suggest widespread misinformation regarding supplements and their effects is an issue for the young athlete. Widespread supplement taking behaviour was evidenced in the young elite athlete population with the most notable congruence between rationale and practice among young athletes being performance-related. Young athletes in the present sample appear to be less 'health conscious' and more 'performance focused' than their adult counterparts. Further research, using a full list of supplements, is warranted to test the hypothesis that health consciousness is less dominant in supplement choice by young athletes.
The purpose of this article is to determine whether some caffeine users endorse clinical indicators of dependence and abuse. We asked 162 randomly-selected caffeine users generic DSM-IV criteria for dependence, abuse, intoxication and withdrawal pertaining to their caffeine use in the last year via a structured telephone interview. The prevalence of endorsement of dependence items was 56% for strong desire or unsuccessful attempt to stop use, 50% for spending a great deal of time with the drug, 28% for using more than intended, 18% for withdrawal, 14% for using despite knowledge of harm, 8% for tolerance and 1% for foregoing activities to use. Seven percent of users met DSM-IV criteria for caffeine intoxication and, among those who had tried to stop caffeine permanently, 24% met DSM-IV research criteria for caffeine withdrawal. Test-retest interviews for dependency agreed in 29/30 cases (97%). Eight expert substance abuse clinicians agreed with self-endorsed caffeine dependence 91% of the time. Our results replicate earlier work and suggest that a substantial proportion of caffeine users exhibit dependence-like behaviors. Further studies are needed to determine whether such users exhibit a clinically significant syndrome of drug dependence.
An otherwise healthy 28-year-old man had a cardiac arrest after a day of motocross racing. He had consumed excessive amounts of a caffeinated "energy drink" throughout the day. We postulate that a combination of excessive ingestion of caffeine- and taurine-containing energy drinks and strenuous physical activity can produce myocardial ischaemia by inducing coronary vasospasm.
To investigate the effects of caffeine ingestion on thermoregulation and fluid-electrolyte losses during prolonged exercise in the heat. Seven endurance-trained ( .VO2max = 61 +/- 8 heat-acclimated cyclists pedaled for 120 min at 63% .VO2max in a hot-dry environment (36 degrees C; 29% humidity) on six occasions: 1) without rehydration (NF); 2) rehydrating 97% of sweat losses with water (WAT); 3) rehydrating the same volume with a 6% carbohydrate-electrolytes solution (CES); or combining these treatments with the ingestion of 6 mg (-1) body weight 45 min before exercise, that is, 4) C(AFF) + NF; 5) C(AFF) + WAT; and 6) C(AFF) + CES. Without fluid replacement (NF and C(AFF) + NF), final rectal temperature (T(REC)) reached 39.4 +/- 0.1 degrees C, whereas it remained at 38.7 +/- 0.1 degrees C during WAT (CES and C(AFF)+ WAT; (P < 0.05). Caffeine did not alter heat production, forearm skin blood flow, or sweat rate. However, C(AFF) + CES tended to elevate T(REC) above CES alone (38.9 +/- 0.1 degrees C vs 38.6 +/- 0.1 degrees C; P = 0.07). Caffeine ingestion increased sweat losses of sodium, chloride, and potassium ( approximately 14%; P < 0.05) and enlarged urine flow (28%; P < 0.05). Caffeine ingested alone or in combination with water or a sports drink was not thermogenic or impaired heat dissipation. However, C(AFF) + CES tended to have a higher T(REC) than CES alone. Caffeine increased urine flow and sweat electrolyte excretion, but these effects are not enough to affect dehydration or blood electrolyte levels when exercising for 120 min in a hot environment.
Media have anecdotally reported that drinking energy drinks in combination with alcohol and exercise could cause sudden cardiac death. This study investigated changes in the electrocardiogram (ECG) and heart rate variability after intake of an energy drink, taken in combination with alcohol and exercise. Ten healthy volunteers (five men and five women aged 19-30) performed maximal bicycle ergometer exercise for 30 min after: (i) intake of 0.75 l of an energy drink mixed with alcohol; (ii) intake of energy drink; and, (iii) no intake of any drink. ECG was continuously recorded for analysis of heart rate variability and heart rate recovery. No subject developed any clinically significant arrhythmias. Post-exercise recovery in heart rate and heart rate variability was slower after the subjects consumed energy drink and alcohol before exercise, than after exercise alone. The healthy subjects developed blunted cardiac autonomic modulation after exercising when they had consumed energy drinks mixed with alcohol. Although they did not develop any significant arrhythmia, individuals predisposed to arrhythmia by congenital or other rhythm disorders could have an increased risk for malignant cardiac arrhythmia in similar situations.