Effects of Caffeine-Taurine Co-Ingestion on Endurance Cycling Performance in High Temperature and Humidity Environments

BACKGROUND

Taurine (TAU) and caffeine (CAF), as common ergogenic aids, are known to affect exercise performance; however, the effects of their combined supplementation, particularly in high temperature and humidity environments, have not been studied.

HYPOTHESIS

The combination of TAU and CAF will have a greater effect on endurance cycle performance and improve changes in physiological indicators during exercise compared with TAU or CAF supplementation alone and placebo.

STUDY DESIGN

Single-blind crossover randomized controlled study.

LEVEL OF EVIDENCE

Level 1.

METHODS

Twelve university students majoring in physical education volunteered to receive 4 different supplement ingestions: (1) placebo (maltodextrin), (2) TAU, (3) CAF, (4) TAU + CAF. After a 7-day washout period, participants completed a time to exhaustion (TTE) test in the heat (35°C, 65% relative humidity).

RESULTS

All experimental groups improved TTE compared with the placebo group. Peak and mean power of countermovement jump were significantly higher in the CAF group compared with the placebo group before the exhaustion exercise (P = 0.02, d = 1.2 and P = 0.04, d = 1.1, respectively). Blood lactate was significantly lower after the exhaustion test in the TAU group compared with the CAF (P < 0.01, d = 0.8) and TAU + CAF (P < 0.01, d = 0.7) groups. Core temperature in the TAU group was significantly reduced in the placebo group later in the exhaustion test (P < 0.01, d = 1.9).

CONCLUSION

In high temperature and humidity environments, acute TAU, CAF, and combined supplementation all improved TTE and did not affect recovery from lower limb neuromuscular fatigue compared with placebo, with TAU having the best effect. Combined supplementation failed to exhibit superimposed performance.

CLINICAL RELEVANCE

The results provide suggestions for the effects of TAU, CAF, and their combined intake on exercise performance in high temperature and humidity environments.

International society of sports nutrition position stand: energy drinks and energy shots

Position Statement: The International Society of Sports Nutrition (ISSN) bases the following position stand on a critical analysis of the literature regarding the effects of energy drink (ED) or energy shot (ES) consumption on acute exercise performance, metabolism, and cognition, along with synergistic exercise-related performance outcomes and training adaptations. The following 13 points constitute the consensus of the Society and have been approved by the Research Committee of the Society: Energy drinks (ED) commonly contain caffeine, taurine, ginseng, guarana, carnitine, choline, B vitamins (vitamins B1, B2, B3, B5, B6, B9, and B12), vitamin C, vitamin A (beta carotene), vitamin D, electrolytes (sodium, potassium, magnesium, and calcium), sugars (nutritive and non-nutritive sweeteners), tyrosine, and L-theanine, with prevalence for each ingredient ranging from 1.3 to 100%. Energy drinks can enhance acute aerobic exercise performance, largely influenced by the amount of caffeine (> 200 mg or >3 mg∙kg bodyweight [BW-1]) in the beverage. Although ED and ES contain several nutrients that are purported to affect mental and/or physical performance, the primary ergogenic nutrients in most ED and ES based on scientific evidence appear to be caffeine and/or the carbohydrate provision. The ergogenic value of caffeine on mental and physical performance has been well-established, but the potential additive benefits of other nutrients contained in ED and ES remains to be determined. Consuming ED and ES 10-60 minutes before exercise can improve mental focus, alertness, anaerobic performance, and/or endurance performance with doses >3 mg∙kg BW-1. Consuming ED and ES containing at least 3 mg∙kg BW-1 caffeine is most likely to benefit maximal lower-body power production. Consuming ED and ES can improve endurance, repeat sprint performance, and sport-specific tasks in the context of team sports. Many ED and ES contain numerous ingredients that either have not been studied or evaluated in combination with other nutrients contained in the ED or ES. For this reason, these products need to be studied to demonstrate efficacy of single- and multi-nutrient formulations for physical and cognitive performance as well as for safety. Limited evidence is available to suggest that consumption of low-calorie ED and ES during training and/or weight loss trials may provide ergogenic benefit and/or promote additional weight control, potentially through enhanced training capacity. However, ingestion of higher calorie ED may promote weight gain if the energy intake from consumption of ED is not carefully considered as part of the total daily energy intake. Individuals should consider the impact of regular coingestion of high glycemic index carbohydrates from ED and ES on metabolic health, blood glucose, and insulin levels. Adolescents (aged 12 through 18) should exercise caution and seek parental guidance when considering the consumption of ED and ES, particularly in excessive amounts (e.g. > 400 mg), as limited evidence is available regarding the safety of these products among this population. Additionally, ED and ES are not recommended for children (aged 2-12), those who are pregnant, trying to become pregnant, or breastfeeding and those who are sensitive to caffeine. Diabetics and individuals with preexisting cardiovascular, metabolic, hepatorenal, and/or neurologic disease who are taking medications that may be affected by high glycemic load foods, caffeine, and/or other stimulants should exercise caution and consult with their physician prior to consuming ED. The decision to consume ED or ES should be based upon the beverage's content of carbohydrate, caffeine, and other nutrients and a thorough understanding of the potential side effects. Indiscriminate use of ED or ES, especially if multiple servings per day are consumed or when consumed with other caffeinated beverages and/or foods, may lead to adverse effects. The purpose of this review is to provide an update to the position stand of the International Society of Sports Nutrition (ISSN) integrating current literature on ED and ES in exercise, sport, and medicine. The effects of consuming these beverages on acute exercise performance, metabolism, markers of clinical health, and cognition are addressed, as well as more chronic effects when evaluating ED/ES use with exercise-related training adaptions.

Dose caffeinated energy drink is a consideration issue for endurance performance

Caffeinated energy drinks are commonly taken to improve exercise performance, but there are few studies on the influence of different doses on an athlete’s performance. We conducted a double-blind, randomized, counter-balanced, and crossover research study to examine the effects of low caffeinated energy drink (Low ED) or high caffeinated energy drink (High ED) supplement on the performance, haematological response, and oxidative stress in triathletes. Twelve male participants underwent three testing sessions separated by weekly intervals, consisting of sprint triathlon training (0.75 km swim, 20 km cycle, and 5 km run). Before and during the trials, participants were randomly provided with either placebo (PLA) group, Low ED group, or High ED group. Exercise performance in the High ED group decreased significantly compared with the PLA and Low ED groups (p < 0.05). However, participants in the Low ED group also experienced an improved performance (p = 0.054). Analysis of variance revealed no differences among the three groups in cortisol and testosterone levels, or the Borg Rating of Perceived Exertion score (p > 0.5). Furthermore, superoxide dismutase (SOD) was reduced with exercise and were lowest in the High ED group. However, compared with PLA, a significant decrease of thiobarbituric acid reactive substances (TBARS) was observed in Low ED and High ED groups (p < 0.05). This indicates that caffeinated energy drink consumption may improve performance and reduce oxidative stress in sprint triathlon athletes. However, individual differences should be considered when supplementing with caffeinated energy drinks to decrease side effects.

The Effects of a Pre-workout Supplement on Measures of Alertness, Mood, and Lower-Extremity Power

Objective

The purpose of this study was to investigate the effects of a multi-ingredient pre-workout supplement (MIPS) on mental and physical performance.

Materials and methods

Fourteen exercise-trained men (n=7) and women (n=7) completed this randomized, placebo-controlled, double-blind, counterbalanced, crossover trial. Participants consumed either a MIPS or a placebo in a randomized, counterbalanced order. Forty-five minutes after consumption, the following assessments were conducted: psychomotor vigilance test (PVT), Profile of Mood States (POMS), vertical jump test, and heart rate and blood pressure. There was a one-week washout period between assessments.

Results

Statistically significant differences were observed between the treatment and placebo groups for the PVT (reaction time: treatment: 286 ± 28 ms, placebo: 306 ± 46 ms, p=0.0371) and POMS (i.e., vigor: treatment: 15.2 ± 14.9, placebo: 9.7 ± 9.6, p=0.0403; fatigue: treatment: 1.0 ± 1.1, placebo: 3.3 ± 3.4, p=0.0100). There were no significant differences between groups for the other indices of mood, false starts from the PVT, and vertical jump.

Conclusion

Based on our findings, the acute consumption of a MIPS produced a significant improvement in a sustained-attention, reaction-timed task as well as measures of vigor and fatigue.

Effects of Caffeinated Energy Drinks on Cardiovascular Responses during Exercise in Healthy Adults: A Systematic Review and Meta-analysis of Randomized Controlled Trials

The impact of caffeinated energy drinks (CED) on the cardiovascular (CV) response to exercise has not been well described. A systematic review and meta-analysis (MA) was conducted on the acute effects of CEDs on CV responses during dynamic, aerobic exercise in 296 healthy adult males (224) and females (72) in 21 randomized controlled trials. During exercise, there was an increase in heart rate (HR) (mean difference (MD), 2.86 bpm, 95% CI, 2.39-3.34 bpm, I2=0%, p<0.00001), and systolic blood pressure (SBP) (MD, 9.02 mmHg, 95% CI, 4.25-13.79 mmHg, I2= 0%, p=0.0002) with consumption of CEDs, compared to controls, but diastolic blood pressure was similar. Insufficient data was available to evaluate rate pressure product (HR X SBP) and exercise-induced arrhythmia. Though changes to HR during exercise were modest, the significant increase in exercise SBP highlights the importance of directly assessing CV effects of CEDs with exercise, especially in individuals prone to hypertension. Novelty Bullets: 1. Exercise SBP in healthy adults is significantly increased during exercise with the consumption of CEDs compared to control, despite limited data. 2. The direct assessment of CV effects of CEDs with exercise highlights the particular relevance to individuals prone to hypertension.

Caffeinated Drinks and Physical Performance in Sport: A Systematic Review

Caffeine (1,3,7-trimethylxanthine) is one of the most common substances used by athletes to enhance their performance during competition. Evidence suggests that the performance-enhancing properties of caffeine can be obtained by employing several forms of administration, namely, capsules/tablets, caffeinated drinks (energy drinks and sports drinks), beverages (coffee), and chewing gum. However, caffeinated drinks have become the main form of caffeine administration in sport due to the wide presence of these products in the market. The objective of this systematic review is to evaluate the different effects of caffeinated drinks on physical performance in various sports categories such as endurance, power-based sports, team sports, and skill-based sports. A systematic review of published studies was performed on scientific databases for studies published from 2000 to 2020. All studies included had blinded and cross-over experimental designs, in which the ingestion of a caffeinated drink was compared to a placebo/control trial. The total number of studies included in this review was 37. The analysis of the included studies revealed that both sports drinks with caffeine and energy drinks were effective in increasing several aspects of sports performance when the amount of drink provides at least 3 mg of caffeine per kg of body mass. Due to their composition, caffeinated sports drinks seem to be more beneficial to consume during long-duration exercise, when the drinks are used for both rehydration and caffeine supplementation. Energy drinks may be more appropriate for providing caffeine before exercise. Lastly, the magnitude of the ergogenic benefits obtained with caffeinated drinks seems similar in women and men athletes. Overall, the current systematic review provides evidence of the efficacy of caffeinated drinks as a valid form for caffeine supplementation in sport.

The Effects of an Energy Drink on Psychomotor Vigilance in Trained Individuals

The psychomotor vigilance test (PVT) measures one's behavioral alertness. It is a visual test that involves measuring the speed at which a person reacts to visual stimuli over a fixed time frame (e.g., 5 min). The purpose of this study was to assess the effects of an energy drink on psychomotor vigilance as well as a simple measure of muscular endurance (i.e., push-ups). A total of 20 exercise-trained men (n = 11) and women (n = 9) (mean ± SD: age 32 ± 7 years; height 169 ± 10 cm; weight; 74.5 ± 14.5 kg; percent body fat 20.3 ± 6.2%; years of training 14 ± 9; daily caffeine intake 463 ± 510 mg) volunteered for this randomized, double-blind, placebo-controlled, crossover trial. In a randomized counterbalanced order, they consumed either the energy drink (ED) (product: BANG^®, Weston Florida) or a similar tasting placebo drink (PL). In the second visit after a 1-week washout period, they consumed the alternate drink. A full 30 min post-consumption, they performed the following tests in this order: a 5-min psychomotor vigilance test, three sets of push-ups, followed once more by a 5-min psychomotor vigilance test. Reaction time was recorded. For the psychomotor vigilance test, lapses, false starts and efficiency score are also assessed. There were no differences between groups for the number of push-ups that were performed or the number of false starts during the psychomotor vigilance test. However, the ED treatment resulted in a significantly lower (i.e., faster) psychomotor vigilance mean reaction time compared to the PL (p = 0.0220) (ED 473.8 ± 42.0 milliseconds, PL 482.4 ± 54.0 milliseconds). There was a trend for the ED to lower the number of lapses (i.e., reaction time > 500 milliseconds) (p = 0.0608). The acute consumption of a commercially available ED produced a significant improvement in psychomotor vigilance in exercise-trained men and women.

Caffeine Improves Triathlon Performance: A Field Study in Males and Females

The ergogenic effect of caffeine on endurance exercise is commonly accepted. We aimed to elucidate realistically the effect of caffeine on triathlon event performance using a field study design, while allowing investigation into potential mechanisms at play. A double-blind, randomized, crossover field trial was conducted. Twenty-six triathletes (14 males and 12 females; mean ± SD: age = 37.8 ± 10.6 years, habitual caffeine intake = 413 ± 505 mg/day, percentage body fat = 14.5 ± 7.2%, and training/week = 12.8 ± 4.5 hr) participated in this study. Microencapsulated caffeine (6 mg/kg body weight) was supplemented 60 min pretrial. Performance data included time to completion, rating of perceived exertion, and profile of mood states. Blood samples taken before, during, and postrace were analyzed for cortisol, testosterone, and full blood count. Capillary blood lactate concentrations were assessed prerace, during transitions, and 3, 6, 9, 12, and 15 min after triathlons. Caffeine supplementation resulted in a 3.7% reduction in swim time (33.5 ± 7.0 vs. 34.8 ± 8.1 min, p < .05) and a 1.3% reduction in time to completion (149.6 ± 19.8 vs. 151.5 ± 18.6 min, p < .05) for the whole group. Gender differences and individual responses are also presented. Caffeine did not alter the rating of perceived exertion significantly, but better performance after caffeine supplementation suggests a central effect resulting in greater overall exercise intensity at the same rating of perceived exertion. Caffeine supplementation was associated with higher postexercise cortisol levels (665 ± 200 vs. 543 ± 169 nmol/L, p < .0001) and facilitated greater peak blood lactate accumulation (analysis of variance main effect, p < .05). We recommend that triathlon athletes with relatively low habitual caffeine intake may ingest 6 mg/kg body weight caffeine, 45-60 min before the start of Olympic-distance triathlon to improve their performance.

Taurine supplementation improves economy of movement in the cycle test independently of the detrimental effects of ethanol

Taurine (TA) ingestion has been touted as blunting the deleterious effects of ethanol (ET) ingestion on motor performance. This study investigated the effects of ingestion of 0.6 mL·kg^-1 of ET, 6 grams of TA, and ethanol in combination with taurine (ET+TA) on economy of movement (EM) and heart rate (HR). Nine volunteers, five female (22 ± 3 years) and four male (26 ± 5 years), participated in a study that used a counterbalanced experimental design. EM and HR were measured for 6 min while the subjects were pedalling at a fixed load 10% below the anaerobic threshold. The blood alcohol concentration (BAC) was similar between ET and ET+TA treatments at 30 min after ingestion and after exercise (12.3 mmol·L^-1 vs. 13.7 mmol·L^-1, and 9.7 mmol • L^-1 vs 10.9 mmol·L^-1, respectively). EM was significantly different among treatments, with lower mL·W^-1 following ingestion of TA (-7.1%, p<0.001) than placebo and ET+TA (-2.45%, p=0.001) compared to ET. HR (bpm) was significantly (p<0.05) higher for ET (137 ± 14 bpm) than the other three treatments (placebo = 129 ± 14 bpm; TA = 127 ± 11 bpm; TA+ET = 133 ± 12 and ET = 137 ± 14 bpm). Taurine improved EM when compared to placebo or ET, and reduced HR when compared to ET. The combination of ET+TA also enhanced EM compared to placebo, and reduced HR in comparison to ET alone. Therefore, these findings indicate that taurine improves EM and counteracts ethanol-induced increases in HR during submaximal exercise.

Effects of Energy Drinks on Economy and Cardiovascular Measures

Peveler, WW, Sanders, GJ, Marczinski, CA, and Holmer, B. Effects of energy drinks on economy and cardiovascular measures. J Strength Cond Res 31(4): 882-887, 2017-The use of energy drinks among athletes has risen greatly. Caffeine and taurine are the 2 primary performance enhancing ingredients found in energy drinks. The number of emergency department visits involving energy drinks doubled over the past 5 years. Reviews of the health complications have highlighted adverse cardiovascular events. The literature reveals that caffeine is known to moderately increase blood pressure (BP) and heart rate (HR). The purpose of this study was to determine the effect of 3 different energy drinks on cardiovascular and performance measures. Fifteen recreational runners completed 5 trials. The first trial consisted of a graded exercise protocol. The 4 remaining trials consisted of 15-minute economy trials at a treadmill speed consistent with 70% of subject's V[Combining Dot Above]O2max. An hour before subjects ingested 1 of the 3 energy drinks or a placebo. HR, BP, V[Combining Dot Above]O2, and rating of perceived exertion (RPE) were recorded during the 15-minute trial. Mean values for dependent measures were compared using repeated-measures analysis of variance. Fifteen-minute systolic BP readings were significantly lower in the placebo trials (156.93 ± 15.50) in relation to the 3 energy drink trials (163.87 ± 13.30, 166.47 ± 13.71, and 165.00 ± 15.23). There were no significant differences in diastolic BP and HR. There were no significant differences found in V[Combining Dot Above]O2 or RPE measures. Ingestion of energy drinks demonstrated no change in V[Combining Dot Above]O2 or RPE during the economy trials. The findings show no performance benefits under the conditions of this study. However, there does appear to be a significant increase in systolic BP.

Effect of energy drink intake before exercise on indices of physical performance in untrained females

Objectives:

To determine the effect of energy drink consumption before exercise on indices of physical performance in untrained females.

Methods:

This single blind placebo controlled experimental study was carried out at the Physiology Department, University of Dammam, Dammam, Kingdom of Saudi Arabia from September 2011 to May 2012, on 32 healthy female students, in a crossover design. They were given either a standardized energy drink or the placebo 45 minutes before the exercise. Time to exhaustion and the stages of Bruce protocol achieved were noted. Heart rate, blood pressure, peripheral capillary oxygen saturation, and blood lactate were recorded before and after the exercise. Maximum oxygen consumption (VO₂max) was calculated by formula. Paired sample t-test was used for statistics.

Results:

The mean age was 19.93±0.8 years, mean height 156.40±3.83 cm, and the mean weight 51.73±3.65 kg. Time to exhaustion in the placebo group was 11.67±1.51 minutes and 11.41±1.56 in the energy drink group (p<0.157). The VO₂max in the placebo group was 34.06±6.62, while it was 32.89±6.83 in the energy drink group (p<0.154). There were no significant differences between the placebo and the energy drinks groups in regards to heart rate, blood pressure, and blood lactate levels, before or after the exercise. However, there were significant differences before, immediately, and 30 minutes post exercise for all parameters between each group.

Conclusion:

The effects of energy drinks intake on physical performance during the exercise in our small sample does not significantly differ from placebo.

Acute effects of caffeine-containing energy drinks on physical performance: a systematic review and meta-analysis

PURPOSE

Caffeine-containing energy drinks (EDs) are currently used as ergogenic aids to improve physical performance in a wide variety of sport disciplines. However, the outcomes of previous investigations on this topic are inconclusive due to methodological differences, especially, in the dosage of the active ingredients and the test used to assess performance.

METHODS

We performed a systematic review and meta-analysis of published studies to evaluate the effects of acute ED intake on physical performance. The search for references was conducted in the databases PubMed, ISI Web of Knowledge and SPORTDiscus until December 2015.

RESULTS

Thirty-four studies published between 1998 and 2015 were included in the analysis. Using a random-effects model, effect sizes (ES) were calculated as the standardized mean difference. Overall, ED ingestion improved physical performance in muscle strength and endurance (ES = 0.49; p < 0.001), endurance exercise tests (ES = 0.53; p < 0.001), jumping (ES = 0.29; p = 0.01) and sport-specific actions (ES = 0.51; p < 0.001), but not in sprinting (ES = 0.14; p = 0.06). The meta-regression demonstrated a significant association between taurine dosage (mg) and performance (slope = 0.0001; p = 0.04), but not between caffeine dosage (mg) and performance (slope = 0.0009; p = 0.21).

CONCLUSION

ED ingestion improved performance in muscle strength and endurance, endurance exercise tests, jumping and sport-specific actions. However, the improvement in performance was associated with taurine dosage.

Taurine and skeletal muscle function

PURPOSE OF REVIEW

To discuss the recent work examining the importance of taurine in skeletal muscle and outline the discrepancy that exists between research findings in rodent vs. human skeletal muscle.

RECENT FINDINGS

There is clear evidence that a normal taurine level is important for the normal functioning of skeletal muscle. Taurine is believed to be involved in many cellular functions, but in skeletal muscle its main roles are to facilitate Ca2+ dependent excitation-contraction processes, contribute to the regulation of cellular volume, and aid in antioxidant defense from stress responses. Most research has studied the importance of taurine in rodent skeletal muscle by downregulating and upregulating the muscle taurine content and examining the effects on the functioning of skeletal muscle at rest and during the stress of contractions (exercise). One successful research approach is to supplement the diet with taurine, which leads to increases in muscle taurine content and contractile function in rodents. However, this approach does not work in human skeletal muscle as the processes involved in the transport of taurine into the muscle are resistant to large and prolonged increases in plasma taurine following oral taurine supplementation. At present, attempts to influence muscle function with taurine supplementation can only occur through interactions outside the muscle cell in humans.

SUMMARY

Future research should target the mechanisms responsible for the transport of taurine into human skeletal muscle and determine why the muscle defends the normal taurine content in the face of elevated plasma taurine levels, as opposed to the results in rodent muscle. This may lead to more fruitful usage of taurine as a skeletal muscle enhancing nutrient in athletic and clinical populations.