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The ergogenic effects of caffeine supplementation on repeated-sprint ability (RSA) have produced equivocal results. This study aimed to examine the effects of 200 mg of caffeine during repeated-sprint running on heart rate (HR), rating of perceived exertion (RPE), blood lactate (BLa) concentration, and sprint time (ST). Thirty-two individuals (males: n = 17, females: n = 15; age: 22 ± 1 years) participated in the study. The study followed a double-blind, randomized, placebo-controlled, crossover design, in which each participant ingested 200 mg of caffeine or placebo on separate visits 60 minutes prior to repeated-sprinting exercise. The repeated-sprint protocol consisted of three sets of six maximal-effort 30-meter sprints with 20 seconds and 5 minutes of active recovery in between sprints and sets, respectively. During each set, HR, RPE, BLa, and ST were recorded. Caffeine supplementation did not significantly (set 1: p = 0.535; set 2: p = 0.602; set 3: p = 0.189) impact HR during exercise. Similarly, RPE was not statistically (p = 0.052) altered between conditions during any of the sprint sets. The caffeine trials elicited greater BLa values after all three sets compared to the placebo trials (p < 0.001). Moreover, the caffeine trials demonstrated significantly reduced total STs during all sets compared to the placebo trials (p < 0.001). Thus, our findings suggested that 200 mg of caffeine supplementation elicited an increase in RSA in young, healthy non-athletes. These findings are accompanied by a blunted perceived exertion relative to an increase in exercise intensity during repeated-sprint exercise. [ABSTRACT FROM AUTHOR]

The placebo effect of caffeine has been poorly investigated in endurance exercise. Therefore, the aim of this study was to analyze the placebo effect of caffeine on 4 km running performance in amateur runners. Twenty-two healthy and recreational male runners (25.5 ± 8.4 yrs; 75.0 ± 7.1 kg; 173.7 ± 6.3 cm) underwent a deceptive experimental design consisting of three different sessions: a) control (CON) in which participants did not ingest any substance; b) placebo (PLA) in which participants ingested a capsule filled with maltodextrin but they were informed that they would receive caffeine; c) caffeine (CAF) in which participants were informed that they would receive caffeine and actually received caffeine. After 60 min for substances absorption, participants performed a 4-km test and they completed the distance as fast as possible. The time employed to cover the distance was lower in PLA (17.4 ± 1.5 min) and CAF (17.4 ± 1.4 min) than CON sessions (18.6 ± 2.8 min; P<0.05). There were no differences in the 4-km times between PLA and CAF (P>0.05) and no differences were reported between treatments for RPE (P>0.05). In conclusion, there was a placebo effect of caffeine on a 4-km maximal running trial which entailed that believing to have ingested caffeine improved performance to a similar extent than actually receiving caffeine. Therefore, the expectancy induced by caffeine may be one of the mechanisms behinds the ergogenic effect of this stimulant on endurance exercise. [ABSTRACT FROM AUTHOR]

Caffeine may impact post-exercise heart rate variability (HRV); although, studies have yielded inconsistent findings. We examined the effects of low dose caffeine on post-exercise HRV. Healthy, college-aged adults [n = 18; age: 22.1 ± 2.6 years; BMI: 26.9 ± 4.3 kg/m2; estimated maximal oxygen consumption (VO2max): 45.1 ± 8.3 ml·kg-1·min-1] participated in a repeated-measures, double-blind, placebo-controlled trial. During the experimental trials, participants were fitted with a heart rate monitor and a mouthpiece with a one-way nonrebreathing valve and then rested for 10 min during baseline HRV and expired gas assessments. Participants chewed either caffeine (~170mg) or placebo gum for 5 min. Following expectoration and a 5 min warmup, participants walked on a treadmill for 20 min at 60% of estimated VO2max and then rested for 30 min. HRV indices were calculated from 10 min measurements during baseline and post-exercise (post 1, 2, and 3). A main effect of treatment was found for standard deviation of RR intervals (SDNN), absolute power of low frequency band (LF), absolute power of high frequency band (HF), and the standard deviation perpendicular to the line-of-identity in Poincaré plot (SD1) (p < 0.05). Further, a trend for higher root mean square of successive RR interval differences (RMSSD) with caffeine was observed (p = 0.066). Post hoc t-tests revealed that post-exercise SDNN, LF, HF, and SD1 were higher with caffeine compared to placebo (p = 0.012). Results demonstrated that low dose caffeine did not delay the recovery of HRV indices reflective of parasympathetic nervous system activity following an acute bout of moderate exercise. [ABSTRACT FROM AUTHOR]

This study examined the effects of a caffeine treatment to improve nuclear reprogramming in porcine cloned embryos. Embryonic development and the expression of genes related to pluripotency (POU5F1, SOX2, NANOG, and CDX2) were compared after caffeine supplementation during manipulation at different concentrations (0, 1.25, 2.5, and 5.0 mM) and after varying the delayed activation time (control, 1, 2, and 4 h) after fusion. Caffeine added to media during manipulation produced a higher rate of development to blastocysts in the 1.25 mM group than in the other concentration groups (22.8% vs. 16.1%, 16.2%, and 19.2%; p < 0.05). When caffeine was added during the 4 h delayed activation, the 1.25 mM caffeine concentration produced a significantly higher rate of development than those in the other 4 h-activation-delayed caffeine concentration groups (22.4% vs. 9.4%, 14.0%, and 11.1%; p < 0.05). On the other hand, no significant improvement over that in the control group was observed when caffeine was supplemented during both the manipulation period and delayed activation period (16.0% vs. 15.2%), respectively. The levels of POU5F1, SOX2, and NANOG expression in blastocysts were significantly higher in the delayed activation caffeine group (4 h, 1.25 mM) than in the control group (1 h, 0 mM; p < 0.05). In conclusion, a caffeine treatment at 1.25 mM during delayed activation for 4 h can improve the preimplantation development of porcine somatic cell nuclear transfer embryos by activating nuclear reprogramming. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the acute effects of caffeine ingestion on flexibility of young females. Twelve young post-pubertal females (age: 17.4 ± 3.2 yrs; weight: 54.6 ± 6.4 kg; height: 162.2 ± 4.0 cm), who were physically active, participated in this study. On the first visit, preliminary measurements and familiarization steps were carried out. During the next two follow-up visits, using a double-blind, counterbalanced and crossover design, the subjects performed a flexibility test 1 hr after ingesting 5 mg∙kg-1 body mass of caffeine or placebo. Both right and left forward splits were significantly improved by caffeine (12.9 ± 9.8 and 19.0 ± 11.4 cm) when compared to the placebo (17.2 ± 8.4 and 25.0 ± 10.7 cm, P<0.05). However, caffeine had no effect on straddle split (P>0.05). The present study reveals that caffeine significantly improved the flexibility of young females. This is an important finding because an improvement in flexibility might promote a better quality of life and a higher performance during competitive sports that require a high level of flexibility. [ABSTRACT FROM AUTHOR]

This study analyzed the effect of caffeine supplementation on cholesterol in vascular occlusion during strength exercise in 12 men. Exercise protocol: 6 sets of bench press with a bar and vascular occlusion, until failure, with 20% of 1RM. Caffeine Supplementation: Intake of 420 mg of caffeine 60 min before exercise. Cholesterol was measured in 6 moments. In the supplement situation, there was a significant decrease during the 45-min recovery compared other moments. In the control situation, there was no significant difference between any of the moments (P>0.05). No significant difference was found between the supplementation and the control situations (P>0.05). The caffeine supplementation had no influence on the subjects' cholesterol in vascular occlusion exercise when compared without supplementation. But, there was a significant within moment difference in the supplementation at the 45-min recovery that shows caffeine may be beneficial in reducing acute cholesterol levels. [ABSTRACT FROM AUTHOR]

Prenatal exposure to caffeine can cause developmental problems. This study determined chronic influence of prenatal caffeine at relatively higher doses on cognitive functions in the rat offspring. Pregnant Sprague-Dawley rats (4-month-old) were exposed to caffeine (20 mg/kg, twice a day) for whole pregnancy from gestational day 4. Fetal and offspring body and brain weight was measured. Learning and memory were tested in adult offspring with Morris water maze. Learning and memory-related receptors were measured. The exposure to prenatal caffeine not only caused fetal growth restriction, but also showed long-term effects on learning and memory in the offspring. The caffeine offspring exhibited longer escape latency and path length in navigation testing. The number of passing the target was significantly reduced in those offspring. The expression of adenosine A1 and A2A receptors, nuclear PKA Cα, Cβ subunits, and pCREB were significantly increased in the fetal and neonatal brain, and suppressed in the hippocampus of the adult offspring. The expression of BDNF and TrkB were reduced regardless of various ages. The results suggest that intrauterine programming dysfunction of adenosine receptors and the down-stream of cAMP/PKA/pCREB system may play an important role in prenatal caffeine induced cognition disorders in the adult offspring. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effect of caffeine on creatine supplementation on electromyographic activity and torque. Sixteen males were supplemented with caffeine (6 mg·kg-1) and creatine (3 g). They did the knee extension test on the isokinetic dynamometer while electromyographic activity was monitored. The caffeine group achieved 4.57% increase in EMG activity and 4.25% increase in torque. The creatine group achieved a 17.07% decrease in the EMG activity and a 3.45% increase in torque. The caffeine and creatine group achieved a 3.07% increase in EMG activity and a 5.79% increase in torque. The findings indicate that the consumption of caffeine at 6 mg·kg-1 in association with 3 g of creatine for 7 days generated a significant improvement in performance, increased the production of torque, and improved the EMG muscle activity. Thus, it is more than reasonable to conclude that caffeine potentiates the effects of creatine during a physical exercise. [ABSTRACT FROM AUTHOR]

Purpose Diet, fluid intake and caffeine, alcohol and tobacco use may have effects on lower urinary tract symptoms. Constructive changes in these modifiable nonurological factors are suggested to improve lower urinary tract symptoms. To better understand the relationship between nonurological factors and lower urinary tract symptoms, we performed a systematic literature review to examine, grade and summarize reported associations between lower urinary tract symptoms and diet, fluid intake and caffeine, tobacco and alcohol use. Materials and Methods We performed PubMed® searches for eligible articles providing evidence on associations between 1 or more nonurological factors and lower urinary tract symptoms. A modified Oxford scale was used to grade the evidence. Results We reviewed 111 articles addressing diet (28 studies), fluid intake (21) and caffeine (21), alcohol (26) and tobacco use (44). The evidence grade was generally low (6% level 1, 24% level 2, 11% level 3 and 59% level 4). Fluid intake and caffeine use were associated with urinary frequency and urgency in men and women. Modest alcohol use was associated with decreased likelihood of benign prostatic hyperplasia diagnosis and reduced lower urinary tract symptoms in men. Associations between lower urinary tract symptoms and ingestion of certain foods and tobacco were inconsistent. Conclusions Evidence of associations between lower urinary tract symptoms and diet, fluid intake and caffeine, alcohol and tobacco use is sparse and mostly observational. However, there is evidence of associations between increased fluid and caffeine intake and urinary frequency/urgency, and between modest alcohol intake and decreased benign prostatic hyperplasia diagnosis and lower urinary tract symptoms. Given the importance of these nonurological factors in daily life, and their perceived impact on lower urinary tract symptoms, higher quality evidence is needed. [ABSTRACT FROM AUTHOR]

This study reports bench-scale feasibility study for production and recovery of theobromine from caffeine using metabolically engineered E. coli . The N 1 -demethylase genes used in this study were originally discovered in Pseudomonas putida CBB5. Five strains of E. coli engineered with multiple combinations of the two N -demethylase genes were compared for growth and activity. Strain pAD1dDD containing one copy of ndmA and three copies of ndmD in two compatible plasmids, gave the best results (98.5% molar conversion of caffeine to theobromine). The reaction was scaled up to 2 L and theobromine was separated and recovered in nearly 100% pure form via preparative chromatography and drying. Final yield was 80% relative to caffeine. Purity of the product was identical to an authentic standard as judged by LC-MS and NMR. This is the first report of theobromine production via a metabolically engineered strain, with the highest yield and purity reported of any biological method. This method also eliminates the harsh reaction conditions and environmental issues associated with the chemical process. [ABSTRACT FROM AUTHOR]

The purpose of this study is to determine how caffeine affects exercise blood pressure (BP) and active and passive recovery BP after vigorous intensity exercise in physically active college-aged females. Fifteen physically active, ACSM stratified low-risk females (age (y): 23.53 ± 4.07, weight (kg): 60.34 ± 3.67, height (cm): 165.14 ± 7.20, BMI (kg/M2): 22.18 ± 1.55) participated in two Bruce protocol exercise tests. Before each test participants consumed 1) a placebo or 2) 3.3 mg·kg-1 of caffeine at least one hour before exercise in a counterbalanced double-blinded fashion. After reaching 85% of their age-predicted maximum heart rate, BP was taken and participants began an active (i.e. walking) recovery phase for 6 minutes followed by a passive (i.e. sitting) recovery phase. BP was assessed every two minutes in each phase. Recovery times were assessed until active and passive BP equaled 20 mmHg and 10 mmHg above resting, respectively. Participants completed each test 1-2 weeks a part. Maximal systolic and diastolic blood pressures were not significantly different between the two trials. Active recovery, passive recovery, and total recovery times were all significantly longer during the caffeine trial than the placebo trial. Furthermore, the time to reach age-predicted maximum heart rate was significantly shorter in the placebo trial than the caffeine trial. While caffeine consumption did not significantly affect maximal blood pressure, it did affect active and passive recovery time following vigorous intensity exercise in physically active females. Exercise endurance also improved after consuming caffeine in this population. [ABSTRACT FROM AUTHOR]

Caffeine increases aerobic performance, but research findings are mixed regarding anaerobic performance (AnP). Thus, the purpose of this study was to investigate the effects of acute caffeine ingestion on high-intensity cycling anaerobic exercise in 14 healthy and physically active non-habitual caffeine users (mean age: 20.93 ± 1.73 yrs). After the subjects were familarized with the Wingate Anaerobic test (WAnT) intensity (on a separate date), placebo or caffeine treatments were performed. Both treatments were separated by 1 wk in a randomized, double-blind manner. One hr before the WAnT, the subjects ingested a drink mixture of water, lemonade, and Sprite as a placebo (PLA) or containing caffeine (CAF, 5 mg·kg-1); both drinks were equal in calories. The WAnT was performed for 30 sec with the resistance set at 7.5% of the subject's body mass. Peak power, mean power, and fatigue index were determined. A paired sample t-test was used to compare the AnP variables between treatments. Heart rate (HR), blood pressure (BP), blood lactate (LA), and glucose (GLU) levels were analyzed with a two-way repeated-measures ANOVA. The results showed no significant effect of caffeine on AnP (P>0.05). Increases in HR, BP, and blood LA levels were independent of treatments (P>0.05). However, blood GLU levels significantly differed between the treatments (P<0.05). The findings indicate that a single dose of CAF was insufficient to elicit an ergogenic effect on AnP in unaccustomed and non-habitual caffeine users. [ABSTRACT FROM AUTHOR]

Background: The positive effects of caffeine supplementation on strength-power and endurance performance in healthy athletes have been demonstrated in many studies. A possible mechanism for its ergogenic effect relates to its influence on the central nervous system. Post-traumatic complications in cervical spinal cord injury affect almost all body systems including the nervous system. For this reason, we expect that caffeine will have a different effect of performance in the group of athletes with spinal cord injuries. Objective: To examine the effects of caffeine supplementation on maximal aerobic power in elite wheelchair rugby players. Methods: Seven elite male wheelchair rugby players with complete cervical-level SCI (C4-Th1) were recruited (mean age: 28 ± 5.42 years; mean body mass index: 26 ± 2.84 kg/m2). The effect of caffeine was assessed by an incremental arm ergometer test until volitional exhaustion. The maximal oxygen uptake (VO2max/kg), maximum power (W max/kg), peak heart rate (HR peak), and intensity of perceived exertion (RPE) were measured. Participants performed the test twice with a two-week washout period. One hour before each exercise test subjects ingested a capsule of placebo or caffeine (3 mg per kg of body weight). The tests were applied in a double-blind, randomized, repeated-measures, and cross-over design. Wheelchair rugby players were chosen because of the expected high homogeneity of participants - in terms of the type and degree of disability, gender, and age of the players. Results: The monitored parameters were not significantly influenced by caffeine intervention as compared to placebo: VO2max/kg (p = .40), W max/kg (p = .34), HR peak (p = .50) and RPE (p = .50). Conclusions: The current findings suggest that a caffeine dose of 3 mg/kg body mass does not improve oxygen uptake and maximal power in elite wheelchair rugby players. [ABSTRACT FROM AUTHOR]

The effects of caffeine on salt chemotaxis learning were investigated using the nematodeCaenorhabditis elegans. To estimate the degree of salt chemotaxis learning, nematodes were placed in a mixed solution of NaCl and caffeine, and then the chemotaxis index of NaCl was obtained from the nematodes placed on agar medium after pre-exposure to caffeine concentrations of 0.01, 0.1, 0.3, and 1.0%. Locomotor activity and preference behavior for caffeine were also estimated under these caffeine conditions. Nematodes pre-exposed to 0.3% caffeine showed inhibition of salt chemotaxis learning. Additional experiments indicated that nematodes showed a preference response to the middle concentration of caffeine (0.1%), with preference behavior declining in the 0.3% caffeine condition. Stable locomotor activity was observed under 0.01–0.3% caffeine conditions. These results suggest that salt chemotaxis learning with 0.3% caffeine is useful for investigating the effects of caffeine on learning in nematodes. We developed the nematode as a model animal for studying the effects of caffeine on learning. Nematodes pre-exposed to 0.3% caffeine showed inhibition of learning. [ABSTRACT FROM PUBLISHER]

The Objective: The goal of the present investigation was to develop and test a brief therapist-guided manualized treatment for problematic caffeine use, including cognitive-behavioral strategies and 5 weeks of progressively decreased consumption. Method: Individuals seeking treatment for problematic caffeine use (mean daily caffeine consumption of 666 mg at baseline) were randomized using a waitlist-control design to receive immediate treatment (N = 33) or delayed treatment (~6 weeks later; N = 34). A 1-hr treatment session designed to help individuals quit or reduce caffeine consumption was provided by a trained counselor along with a take-home booklet. After the treatment session, participants completed daily diaries of caffeine consumption for 5 weeks. They returned for follow-up assessments at 6, 12, and 26 weeks and had a telephone interview at 52-weeks posttreatment. Results: Treatment resulted in a significant reduction in self-reported caffeine use and salivary caffeine levels. No significant posttreatment increases in caffeine use were observed for up to 1 year follow-up. Comparisons to the waitlist-control condition revealed that reductions in caffeine consumption were due to treatment and not the passing of time, with a treatment effect size of R² = .35 for the model. Conclusion: A brief 1-session manualized intervention with follow-up was efficacious at reducing caffeine consumption. Future researchers should replicate and extend these findings, as well as consider factors affecting dissemination of treatment for problematic caffeine use to those in need. [ABSTRACT FROM AUTHOR]

Caffeine enhances aerobic performance, but research is equivocal regarding anaerobic performance. This study examined effects of caffeine (7 mg/kg) on anaerobic performance in anaerobically active males (n = 10). Participants completed counterbalanced, double blind caffeine (Caf) and placebo (Pl) trials including a) 6 x 15 s upper body Wingates (UWant), b) 6 x 15 s lower body Wingates (LWant) and c) 6 x 15 s maximal effort static hand grip test (HG) with 3 min recovery between bouts, 30 min between exercises. Peak power (Ppeak), mean power (Pmean), and heart rate (HR) as well as perceptual measures included ratings of perceived exertion (RPE), muscle pain perception (MPP), and perceived recovery status (PRS) were recorded per bout. Session RPE (S-RPE) (15 min post) for each exercise mode and trial RPE (T-RPE) [10 min post relative to testing period for each treatment (Caf vs. Pl)]. A series of 2 (trial) x 6 (bout) ANOVA's assessed differences and Tukey's LSD post hoc test were used when necessary. Results showed increased performance (main effect) (UWant) for Ppeak (Caf: 6.72 ± 1.2 W/kg vs. Pl: 6.41 ± 1.0 W/kg); and Pmean (Caf: 5.39 ± 0.8 W/kg vs. Pl: 5.18 ± 0.8 W/kg); however no significant main effect for LWant or HG was observed. No significant differences were observed for perceptual measures. Caf improved anaerobic performance in repeated UWant (bouts 1-4) but not LWant or HG. Further studies are warranted to examine Caf ergogenic properties in repeated exercises dominated by anaerobic metabolic pathways given the equivocal results. [ABSTRACT FROM AUTHOR]

This literature review examines the relationship between caffeine and various health effects. This paper will review the research on health risks related to caffeine consumption and weigh the balance between the risks and benefits that caffeine can provide. Although there are several risks correlated with caffeine consumption, this literature review highlights how the benefits may offset any potentials risks. The main benefits that will be discussed are enhancing physical performance, alertness, pain relief, reducing cognitive impairment, hydration, and reducing the risk of cardiovascular and cerebrovascular diseases. [ABSTRACT FROM AUTHOR]

Abstract: I have used Ca2+- and pH-sensitive microelectrodes in and on large neurones in isolated ganglia of Helix aspersa to measure changes in intracellular Ca2+ (as V Ca) and surface pH caused by caffeine (20mM) application, and compared these changes with those caused by iontophoretic injection of Ca2+. Mitochondrial uptake was blocked by pressure-injection of Ru360. In 8 experiments the mean increase in V Ca in response to caffeine was 27.3±2.8mV (SEM) equivalent to a peak tenfold increase in ionised Ca2+. Iontophoretic injection of Ca2+ into the same 8 cells showed that the caffeine responses were equivalent to those caused by an average injection charge of 235±41nC. Surface pH changes produced by the PMCA pumping out Ca2+ released by caffeine averaged 0.025±.005 pH units (n =7), which was equivalent to surface pH changes induced by an average Ca2+ injection charge of 300±86nC. The average cell volume was 4.2nl. Assuming that the injection transport index was 0.48 as previously measured, these V Ca and pH changes suggest that the total Ca2+ content released by caffeine was about 0.175mmol/l cell volume. [Copyright &y& Elsevier]

To date there have been a number of studies that have assessed the effects of caffeine on Rated Perceived Exertion (RPE) and Pain Scale scores during continuous exercise. Presently there is little information about the effects of caffeine on RPE and Pain Scale scores during short term, anaerobic and muscle endurance activity. The purpose of the present investigation was to assess the effects of low-dose caffeine administration on RPE and Pain Scale scores after the one-minute pushup test and the Wingate Anaerobic cycling test. Ten college-aged males were recruited to participate in the investigation. The subjects were given either a piece of caffeinated chewing gum designed to deliver 100 mg of Caffeine in a buccal manner, or a placebo gum with identical shape and flavoring in a double-blind, placebo controlled, repeated measures design. The subjects chewed the gum (caffeine or placebo) for five minutes to allow for caffeine absorption and subsequently performed the one-minute push-up test followed by the Wingate anaerobic test. Subjects responded to the standard Borg RPE scale and the Mosby 10-pt pain scale immediately after each test. The results of the study did not demonstrate any significant difference in performance on either assessment, nor in the responses to the pain scale or RPE scale (p>0.05). It appears based upon this data that low-dose buccal caffeine is neither an effective ergogenic aid nor analgesic for muscle endurance or anaerobic efforts. [ABSTRACT FROM AUTHOR]

Purpose: We examined the effect of caffeine (Sigma®) on voiding patterns in mice and characterized potential changes in bladder function and sensory signaling. Materials and Methods: A total of 12 mice were fed high dose (150 mg/kg) caffeine daily for 2 weeks. Micturition frequency and volume were recorded at baseline and at the end point. The effects of chronic low dose (10 mg/kg) caffeine on voiding patterns were examined in 7 mice, which were subsequently studied using awake cystometry. In a separate study to characterize the effects of acute caffeine consumption on bladder function and sensory signaling cystometry was performed in 6 mice. Bladder extracellular multifiber afferent signaling was recorded at baseline and 1 hour after feeding low dose caffeine. In a separate group of mice baseline cystometrograms were done using normal saline, followed by a caffeine filling solution. Results: Compared to pretreatment conditions, daily oral high dose caffeine resulted in a significant increase in average micturition frequency and a decreased average volume per void. In animals fed low dose caffeine cystometry demonstrated a statistically significant increase in filling and threshold bladder pressure compared to caffeine naïve animals. Acute low dose caffeine ingestion resulted in a significant increase in filling pressure, an increased frequency of nonvoiding bladder contractions, a decrease in cystometric capacity and a 7.2-fold increase in the average firing rate of afferent nerves during filling. Caffeine administered intravesically had no effect on cystometric parameters. Conclusions: Oral caffeine administration results in detrusor overactivity and increased bladder sensory signaling in the mouse. [ABSTRACT FROM AUTHOR]

The article examines the effects of orally administered L-theanine or intake of caffeine on physiological and mental performance in humans. It notes that L-theanine is found helpful to stop the binding of L-glutamic acid to glutamate receptors in the brain. It emphasizes that L-theanine can decrease anxiety and attenuate the blood-pressure in adults with high-stress-response. It also mentions that the intake of caffeine inhibited smaller portion of blood pressure caused by the mental tasks.

Caffeine is a naturally-occurring substance that is found in drinks such as tea and coffee, popular cola-type soft drinks that have been flavoured with extracts from the kola nut, energy drinks, and cocoa and chocolate (when derived from cacao pods). Worldwide, most adults consume caffeine-containing products on a regular basis, as an indulgence, a habit, or a necessity. The sensible use of caffeine may have several advantages, including increased performance in the workplace. Humans ingest caffeine in a number of different ways, frequently using it as a mild central nervous system stimulant. However, caffeine may also have a downside, when used excessively or even abused, which could result in caffeinism, or caffeine dependence. [ABSTRACT FROM AUTHOR]

Repeated postnatal caffeine treatment of rat pups led to transient developmental changes in cortical epileptic afterdischarges. To know if physiological cortical functions are also affected transcallosal evoked potentials were studied. Rat pups of the Wistar strain were injected daily with caffeine (10 or 20 mg/kg s.c.) from postnatal day (P) 7 to P11, control siblings received saline. Cortical interhemispheric responses were tested at P12, 18, 25 and in young adult rats. Amplitude of initial monosynaptic components was evaluated in averaged responses. Single pulses as well as paired and frequency (five pulses) stimulations were used. Developmental rules - highest amplitude of responses in 25-day-old rats, potentiation with paired and frequency stimulation present since P18 - were confirmed. Caffeine-treated rats exhibited transient changes: single responses were augmented in P25 if high stimulation intensity was used, paired-pulse and frequency responses were higher in experimental than in control animals at P12, the opposite change was observed in 18- and more markedly in 25-day-old rats. No significant changes were found in adult animals, monosynaptic transcallosal responses represent a simple and robust system. The developmental profile of described changes did not exactly correspond to changes in epileptic afterdischarges supporting the possibility that afterdischarges did not arise from early monosynaptic components of responses. In spite of transient nature of changes they can reflect delayed or more probably modified brain development. [ABSTRACT FROM AUTHOR]

The article focuses on the right nutrition in fueling and training an ultraendurance athlete. It states that new researches on nutrition for athletes focuses on the performances of the congestion of several types of carbohydrates for race fueling and on the carbohydrate application while training and its impact on metabolism and macronutrient. It also mentions the usage of sodium and caffeine for athletes.

Aphidicolin (APH), an inhibitor of DNA polymerase α, arrested cell divisions in Tetrahymena thermophila. Surprisingly, low concentrations of APH induced an increase of macronuclear DNA content and cell size in non-dividing cells. In spite of the cell size increase, most proliferation of basal bodies, ciliogenesis and development of new oral primordia were prevented by the APH treatment. The division arrest induced by APH was partly overridden by caffeine (CAF) treatment, which caused the fragmentation (“pulverization”) of the chromosomes in G2 micronuclei. Somatic progeny of dividers with pulverized micronuclei (APH+CAF strains) contained aneuploid and amicronucleate cells. The amicronucleate cells, after losing their oral structures and most of their cilia, and undergoing progressive disorganization of cortical structures, assumed an irregular shape (“crinkled”) and were nonviable. “Crinkled” cells were not formed after APH + CAF treatment of the amicronuclear BI3840 strain, which contains some mic-specific sequences in its macronucleus. Most of the APH +CAF strains had a typical “*”- like conjugation phenotype: they did not produce pronuclei, but received them unilaterally from their mates and retained old macronuclei. However, 4 among 100 APH+CAF clones induced arrest at meiotic metaphase I in their wt mates. It is likely that the origin of such clones was enhanced by chromosome pulverization. [ABSTRACT FROM AUTHOR]

Purpose: Although caffeine consumption is common and generally believed to affect bladder function, little is known about caffeine intake and incident urinary incontinence. Materials and Methods: We performed a prospective cohort study in 65,176 women 37 to 79 years old without incontinence in the Nurses'' Health Study and the Nurses'' Health Study II. Incident incontinence was identified from questionnaires during 4 years of followup. Caffeine intake was measured using food frequency questionnaires administered before incontinence development. The multivariate adjusted relative risk of the relation between caffeine intake and incontinence risk as well as attributable risk were calculated. Results: Caffeine was not associated with incontinence monthly or more. However, there was a modest, significantly increased risk of incontinence at least weekly in women with the highest (greater than 450 mg) vs the lowest (less than 150 mg) daily intake (RR 1.19, 95% CI 1.06–1.34) and a significant trend of increasing risk with increasing intake (p for trend = 0.01). This risk appeared focused on incident urgency incontinence (greater than 450 vs less than 150 mg daily, RR 1.34, 95% CI 1.00–1.80, p for trend = 0.05) but not on stress or mixed incontinence (p for trend = 0.75 and 0.19, respectively). The attributable risk of urgency incontinence associated with high caffeine intake was 25%. Conclusions: Findings suggest that high but not lower caffeine intake is associated with a modest increase in the incidence of frequent urgency incontinence. A fourth of the cases with the highest caffeine consumption would be eliminated if high caffeine intake were eliminated. Confirmation of these findings in other studies is needed before recommendations can be made. [Copyright &y& Elsevier]

A small increase in performance is often the difference between winning and losing for athletes, and energy supplements are marketed to give them a competitive edge. One such supplement is XS® Energy Drink which contains B vitamins, caffeine, taurine, and an herbal adaptogen blend. XS® Energy Drink is primarily designed and marketed as an alertness stimulus; however, it is also marketed to athletes as a performance enhancing supplement. The hypothesis of this investigation was that the consumption of XS® Energy Drink before exercise would increase aerobic capacity (an increase in Vo2max) and time to fatigue, and would decrease time for recovery from the exercise bout. Twelve 18-24 year old athletes performed two Vo2max tests following a modified Ellestad Treadmill protocol. Prior to testing, a double-blind cross-over method was used to administer the energy supplement or the placebo. Vo2max (p=0.99), time to muscle fatigue (p=0.48), maximum heart rate (p=0.66), VEmax (p=0.10), time at which R is greater than 1 (p=0.50), or recovery time to one half Vo2max (p=0.67) were not significantly different with ingestion of XS® Energy Drink over placebo. The second trial was significantly longer than the first (p=0.01) likely due to the desire to improve exercise time or familiarization with the testing procedures. Results showed no physiological effects of XS® Energy Drink; however, there is a possibility of psychological advantage. Supported by a Wright State University undergraduate research fellowship and a Wright State University Honors Program grant to KMS. [ABSTRACT FROM AUTHOR]

Abstract: Caffeine, one of the world''s most popular psychoactive substances, is sought for its central nervous system stimulant effects. If coffee, tea, and soda alone do not provide the desired stimulation, some consumers are turning to the newest fad in the caffeine market, energy drinks. These beverages are loaded with caffeine and sugar, infused with herbal additives, and marketed particularly to youth. Caffeine produces dose-dependent symptoms, and intoxication may develop with overconsumption. Caffeine is also recognized for its addictive properties, and discontinuation results in a withdrawal syndrome. Nurse practitioners are encouraged to consider caffeine intoxication, addiction, and withdrawal syndrome in the differential when patients complain of characteristic symptoms. Ongoing nutritional assessment and education on moderation are key to reducing the overuse of caffeinated energy drinks. [Copyright &y& Elsevier]

Abstract: Sarcoplasmic reticulum contains the internal Ca2+ store in smooth muscle cells and its lumen appears to be a continuum that lacks diffusion barriers. Accordingly, the free luminal Ca2+ level is the same all throughout the SR; however, whether the Ca2+ buffer capacity is the same in all the SR is unknown. We have estimated indirectly the luminal Ca2+ buffer capacity of the SR by comparing the reduction in SR Ca2+ levels with the corresponding increase in [Ca2+] i during activation of either IP3Rs with carbachol or RyRs with caffeine, in smooth muscle cells from guinea pig urinary bladder. We have determined that carbachol-sensitive SR has a 2.4 times larger Ca2+ buffer capacity than caffeine-sensitive SR. Rapid inhibition of SERCA pumps with thapsigargin revealed that this pump activity accounts for 80% and 60% of the Ca2+ buffer capacities of carbachol- and caffeine-sensitive SR, respectively. Moreover, the Ca2+ buffer capacity of carbachol-sensitive SR was similar to caffeine-sensitive SR when SERCA pumps were inhibited. Similar rates of Ca2+ replenishments suggest similar levels of SERCA pump activities for either carbachol- or caffeine-sensitive SR. Paired pulses of caffeine, in conditions of low Ca2+ influx, indicate the relevance of luminal SR Ca2+ buffer capacity in the [Ca2+] i response. To further study the importance of luminal SR Ca2+ buffer capacity in the release process we used low levels of heparin to partially inhibit IP3Rs. This condition revealed carbachol-induced transient increase of luminal SR Ca2+ levels provided that SERCA pumps were active. It thus appears that SERCA pump activity keeps the luminal SR Ca2+-binding proteins in the high-capacity, low-affinity conformation, particularly for IP3R-mediated Ca2+ release. [Copyright &y& Elsevier]

Copyright of Pesquisa Brasileira em Odontopediatria e Clinica Integrada is the property of Pesquisa Brasileira em Odontopediatria e Clinica Integrada Journal (Brazil) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: Epidemiological studies have found an inverse association between coffee consumption and the risk of liver cancer. Animal data support such a chemopreventive effect of coffee. Substantial research has been devoted to the identification of coffee components that may be responsible for these beneficial effects. Based on the current available literature, three major components, i.e. coffee diterpenes cafestol and kahweol (C+K), caffeine and chlorogenic acid contribute to the beneficial effects. These components induce phase II detoxifying and antioxidant enzymes as well as inhibit the expression or decrease the activity of phase I activating enzymes thus prevent carcinogenesis. These components target different stages of a common pathway, Kelch-like ECH-associated protein 1 (Keap1) – NF-E2-related factor-2 (Nrf2) – antioxidant-responsive-element (ARE) signal pathway thus alter the ARE-dependent expression of genes needed in the anti-tumorigenic effects. [Copyright &y& Elsevier]

Copyright of Saúde & Tecnologia is the property of Escola Superior de Tecnologia da Saude de Lisboa-ESTESL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To describe benefits and adverse effects associated with the consumption of energy drinks. Data sources: Searches were conducted using Medline, IPA (International Pharmaceutical Abstracts), EMBASE, and MANTIS; databases such as Natural Medicines Comprehensive Database, Natural Standard, ALTMEDEX, and AltHealthWatch; and Google (range 1980 to September 2007). Search terms included energy drink, Red Bull, caffeine, glucose, ginseng, guarana, taurine, and bitter orange. Data synthesis: Most energy drinks contain natural products such as guarana, ginseng, and taurine. As much as 80 to 300 mg of caffeine and 35 grams of processed sugar per 8-ounce serving are commonly present in energy drinks such as Cocaine, Pimp Juice, Red Bull, and Spike Shooter. No reports were identified of negative effects associated with taurine, ginseng, and guarana used in the amounts found in most energy drinks. Commonly reported adverse effects seen with caffeine in the quantities present in most energy drinks are insomnia, nervousness, headache, and tachycardia. Four documented case reports of caffeine-associated deaths were found, as well as four separate cases of seizures associated with the consumption of energy drinks. Conclusion: The amounts of guarana, taurine, and ginseng found in popular energy drinks are far below the amounts expected to deliver either therapeutic benefits or adverse events. However, caffeine and sugar are present in amounts known to cause a variety of adverse health effects. [ABSTRACT FROM AUTHOR]

Abstract: In short-term studies, caffeine has been shown to increase insulin levels, reduce insulin sensitivity, and increase cortisol levels. However, epidemiological studies have indicated that long-term consumption of beverages containing caffeine such as coffee and green tea is associated with a reduced risk of type 2 diabetes mellitus. There is a paucity of randomized studies addressing the metabolic and hormonal effects of consuming caffeine over periods of more than 1 day. We evaluated the effect of oral intake of 200 mg of caffeine taken twice a day for 7 days on glucose metabolism, as well as on serum cortisol, dehydroepiandrosterone (DHEA), and androstenedione, and on nighttime salivary melatonin. A double-blind, randomized, placebo-controlled crossover study with periods of 7 days and washouts of 5 days comparing caffeine with placebo capsules was conducted. Participants were 16 healthy adults aged 18 to 22 years with a history of caffeine consumption. Blood samples from each subject were assayed for glucose, insulin, serum cortisol, DHEA, and androstenedione on the eighth day of each period after an overnight fast. Nighttime salivary melatonin was also measured. Insulin levels were significantly higher (by 1.80 μU/mL; 95% confidence interval, 0.33-3.28) after caffeine intake than after placebo. The homeostasis model assessment index of insulin sensitivity was reduced by 35% (95% confidence interval, 7%-62%) by caffeine. There were no differences in glucose, DHEA, androstenedione, and melatonin between treatment periods. This study provides evidence that daily caffeine intake reduces insulin sensitivity; the effect persists for at least a week and is evident up to 12 hours after administration. [Copyright &y& Elsevier]

The article discusses the use of Energy Drink in sports. Topics include rise in energy drink use in the sporting world has been exponential as few products have inserted themselves into athlete's lives the way that caffeine-laden energy drinks have over the last 30 years; and Energy drinks are nonalcoholic beverages typically comprised of solutions of sugar and carbohydrate, moderate to high amounts of caffeine, and a variety of other proprietary chemicals to have energy-giving properties.

The article discusses the result of the study regarding the effect of caffeine on the body fat and lipid metabolism of rats fed on a high-fat diet, in Japan. Based from the study, the intake of caffeine (CF) for a considerable number of days had reduced the body fat mass and body fat percentage in Sprague-Dawley rats. The rats were fed based on a high-fat diet with increasing administration level. The intake of CF reduced the body fat by lipolysis through catecholamines, as what the results show.

Intake of coffee, one of the most common beverages worldwide, is often reported as a cardiovascular risk factor; however, definitive data are lacking. Acute intake of coffee or beverages containing caffeine can increase blood pressure, heart minute volumes, and cardiac index, as well as activate the sympathetic nervous system in nonhabitual coffee drinkers. Interestingly, this is not observed in habitual coffee drinkers. Restriction of coffee or caffeinated beverages is no longer indicated in the seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) guidelines for the treatment of hypertension. In fact, no clear association between coffee and the risk of hypertension, myocardial infarction, or other cardiovascular diseases has been demonstrated. In contrast to early studies, recent research indicates that habitual moderate coffee intake does not represent a health hazard and may even be associated with beneficial effects on cardiovascular health. [ABSTRACT FROM AUTHOR]

Presents medical information on Caffeine Anaphylaxis. Details on caffeine allergy symptoms; Similarity of symptoms with attention deficit hyperactivity disorder; Health risks associated with caffeine toxicity; Impact of caffeine anaphylaxis on child health.

Background: The general public widely consumes caffeine 1,3,7-trimethylxanthine), which is contained in various foods, beverages and over-the-counter medications. We have shown previously that caffeine intake could affect bone metabolism in vivo. Methods: Because prostaglandin E2 (PGE2) is shown to be elevated in the periodontally diseased site, the possible interaction between caffeine and PGE2 was investigated in the present study using UMR106-01 rat osteoblast-like cells in vitro. Results: Although neither 0.1 mM caffeine nor 0.1 µg/ml of PGE2 alone showed any inhibitory effects on cell proliferation, the combination of caffeine and PGE2 showed significant inhibition. However, in order to have inhibitory effects, both caffeine and PGE2 had to be present at least 72 or 96 hours in the medium. Addition of the endogenous PGE2 synthesis inhibitor, indomethacin, showed no effects on cell proliferation. Neither cAMP-inducing agent IBMX (0.01 mM and 0.1 mM) nor forskolin (0.001 mM) inhibited cell proliferation, but combined with PGE2 these agents strongly inhibited proliferation ns was observed with the combination of caffeine and PGE2, suggesting possibly that the increase of intracellular cAMP concentration plays an important role in the inhibitory effects of cell proliferation. Conclusions: The present data for the first time demonstrate the possible implication of routine caffeine intake in the acceleration of pathological conditions of periodontitis. Thus, we propose that chronic caffeine intake is one of the possible risk factors in the advancement of pathology in the periodontitis patient Further research in this area is warranted. [ABSTRACT FROM AUTHOR]

The administration of caffeine has been developed as a chemical model for the study of anxiety. However, previous researchers investigating caffeine-induced anxiety states in humans have administered oral caffeine. In this dose-response study, we investigated the effects of blindly administered intravenous caffeine (3, 5, and 7 mg/kg) versus placebo in normal control subjects. We report the first series of subjects experiencing olfactory hallucinations (10 of 10 subjects, 24 of 30 infusions) immediately following intravenous caffeine infusion. In addition, consistent with our previous work with oral caffeine, we found dose-related increases in ratings of anxiety and blood levels of cortisol and lactate. One subject experienced a DSM-III-R panic attack. Further questioning revealed that his mother suffers panic attacks. Our findings of olfactory hallucinations are discussed within the context of localized limbic system dysfunction, noting the phenomenologic and possible neuroanatomic overlap between panic disorder and complex partial seizures. [ABSTRACT FROM AUTHOR]

Studies the effect of two doses of caffeine on peak torque and muscle endurance in the knee extensors and flexures. Methods; Results; Discussion.