The effect of acute caffeine ingestion on upper body anaerobic exercise and cognitive performance

Wearables in Chronomedicine and Interpretation of Circadian Health

Wearable devices have gained increasing attention for use in multifunctional applications related to health monitoring, particularly in research of the circadian rhythms of cognitive functions and metabolic processes. In this comprehensive review, we encompass how wearables can be used to study circadian rhythms in health and disease. We highlight the importance of these rhythms as markers of health and well-being and as potential predictors for health outcomes. We focus on the use of wearable technologies in sleep research, circadian medicine, and chronomedicine beyond the circadian domain and emphasize actigraphy as a validated tool for monitoring sleep, activity, and light exposure. We discuss various mathematical methods currently used to analyze actigraphic data, such as parametric and non-parametric approaches, linear, non-linear, and neural network-based methods applied to quantify circadian and non-circadian variability. We also introduce novel actigraphy-derived markers, which can be used as personalized proxies of health status, assisting in discriminating between health and disease, offering insights into neurobehavioral and metabolic status. We discuss how lifestyle factors such as physical activity and light exposure can modulate brain functions and metabolic health. We emphasize the importance of establishing reference standards for actigraphic measures to further refine data interpretation and improve clinical and research outcomes. The review calls for further research to refine existing tools and methods, deepen our understanding of circadian health, and develop personalized healthcare strategies.

Low-Dose Caffeine Supplementation Is a Valuable Strategy for Increasing Time to Exhaustion, Explosive Power, and Reducing Muscle Soreness in Professional Male Kickboxers

Background

Caffeine is a well-established ergogenic aid that enhances physical performance and recovery. However, its dose-dependent effects on key performance metrics in combat sports like kickboxing remain insufficiently explored.

Objective

This study aimed to evaluate the effects of varied doses of acute caffeine supplementation on performance indices and perceived muscle pain in kickboxing athletes.

Methods

Twelve kickboxing athletes participated in 3 exercise sessions with either caffeine supplementation (3 mg/kg [C3], 6 mg/kg [C6]) or placebo (PLA). A 1-wk washout period occurred between exercise trials. Caffeine was supplemented 60 min before each exercise session. In each session, participants first performed a vertical jump and the Wingate anaerobic tests. After a 45-min rest, they completed the Bruce maximal aerobic treadmill test. Measured performance variables included vertical jump height, Wingate test outcomes (relative power [peak, mean power, and lowest], and fatigue index), maximal oxygen consumption (VO₂max), oxygen consumption at the ventilatory threshold (VT2), time-to-exhaustion, rating of perceived exertion (RPE), and muscle soreness assessed immediately, at 2 h, and 12 h postexercise.

Results

C3 and C6 significantly increased time-to-exhaustion following treadmill testing (P < 0.05) but had no effect on the Wingate fatigue index (P > 0.05). Compared with PLA, C3 and C6 significantly increased vertical jump (P < 0.05). C3 significantly increased relative peak power (P < 0.05), whereas C6 and PLA did not during the Wingate test (P > 0.05). Muscle soreness after 2 h showed a significant decrease after C6 compared with C3 and PLA (P < 0.05). In contrast, no significant effect was observed for VO2max, %VO2max at VT2, and RPE (P > 0.05) for all treatments.

Conclusions

Acute supplementation of 3 to 6 mg/kg doses of caffeine-induced relative improvements in anaerobic and lower-body muscular power, muscle soreness, and time-to-exhaustion in male kickboxing athletes.

Caffeinated Chewing Gum Improves Basketball Shooting Accuracy and Physical Performance Indicators of Trained Basketball Players: A Double-Blind Crossover Trial

(1) Background: This study investigated the effects of caffeinated chewing gum on the basketball-specific performance of trained basketball players. A double-blind, randomized crossover design was employed. (2) Methods: Fifteen participants (age: 20.9 ± 1.0 years; height: 180.9 ± 5.4 cm; mass: 77.2 ± 7.5 kg; training age: 8.2 ± 0.3 years) were recruited and divided into a caffeine trial (CAF) and placebo trial (PL). The participants in the CAF trial chewed gum containing 3 mg/kg of caffeine for 10 min, while those in the PL trial chewed a placebo gum without caffeine. Following a 15 min rest, all the participants completed basketball-specific performance tests. (3) Results: The free throw accuracy for the CAF trial was significantly higher than that for the PL trial (CAF: 79.0 ± 4.31%; PL: 73.0 ± 9.16%; p = 0.012; Cohen's d = 0.94). Additionally, the CAF trial demonstrated significantly better performance in the 20 m segmented dash (CAF: 2.94 ± 1.12 s; PL: 3.13 ± 0.10 s; p < 0.001; Cohen's d =1.8) and squats (p < 0.05), and exhibited lower fatigue indexes (CAF: 3.6 ± 1.6%; PL: 5.2 ± 1.6%; p = 0.009; Cohen's d =1.0). (4) Conclusions: These findings suggest that chewing gum containing 3 mg/kg of caffeine offers moderate-to-large improvements in key performance aspects relevant to professionally trained basketball players.

Effects of Various Caffeine Doses on Cognitive Abilities in Female Athletes with Low Caffeine Consumption

Caffeine (CAF), a prevalent psychoactive stimulant, is believed to potentially enhance cognitive ability. However, studies on the effects of various doses are limited and yield inconsistent results, particularly in female athletes. Therefore, we aimed to assess the association between three different dosages of CAF intake (low, moderate, and high) and cognitive skills in female athletes with low CAF consumption. This study had a randomized, crossover, double-blind design in which each athlete performed four experimental sessions after ingesting either a placebo (PLAC), 3 mg·kg-1 of CAF (3 mg of CAF), 6 mg·kg-1 of CAF (6 mg of CAF), or 9 mg·kg-1 of CAF (9 mg of CAF) with an in-between washout period of at least 72 h. Following a 60 min window post-capsule consumption, fourteen female athletes (age: 17.4 ± 0.8 years) were assessed through various cognitive tests, namely, simple reaction time (SRT), choice reaction time (CRT), and attentional task (AT) tests, along with the mental rotation test (MRT). Additionally, they were required to complete a questionnaire about the undesirable side effects of CAF. Our results indicated that, compared to those of PLAC, the SRT, CRT, and AT performance were significantly improved following the administration of both 3 mg of CAF and 6 mg of CAF. While the greatest enhancement was observed after consuming 3 mg of CAF, no significant differences were found between the effects of 3 mg and 6 mg of CAF. Interestingly, MRT performance did not improve with any of the CAF dosages. Moreover, the ingestion of 9 mg of CAF did not enhance cognitive skills and was linked to the highest occurrence of CAF-related side effects. In conclusion, our results highlight the recommendation for a low CAF dosage of 3 mg·kg-1, in contrast to a higher dose of 6 mg·kg-1 or 9 mg·kg-1 of CAF, to enhance various aspects of cognitive performance in female athletes with low CAF consumption without adverse side effects.

The effects of acute caffeine ingestion on decision-making and pass accuracy in young soccer players: A preliminary randomized controlled trial

Caffeine has been shown to benefit physical aspects of different sports. In this paper, we aimed to understand the effects of caffeine on decision-making and the accuracy of soccer passes. Twelve young soccer players (16-17 years old and 20.8±2.7kg/m2 BMI) completed the tasks once after taking 3mg/kg body mass of caffeine (CAF) and once after consuming similar amounts of placebo (PLA). For the decision-making task, participants were asked to determine the best outcome of ten simulated pre-recorded soccer events. For the soccer pass accuracy, participants performed five short- (10m) and five long passes (30m), as well as the Loughborough Soccer Passing Test. Although not statistically significant, participants were 1.67% more accurate in short- and 13.48% more accurate in long passes when they consumed caffeine compared to the placebo (14.67±2.74 vs. 14.50±2.97, p=0.34, g=0.27 and 7.50±2.84 vs. 6.83±3.13, p=0.60, g=0.14, respectively). However, participants' decision-making was 7.14% and LSPT scores were 3.49% lower when they consumed caffeine compared to the placebo (29.50±3.09 vs. 30.67±2.93, p=0.28, g=-0.30 and 55.38±11.91 vs. 57.48±12.13, p=0.08, g=-0.51 respectively). In conclusion, while the short pass accuracy remained consistent among almost all participants before and after caffeine consumption, the performance varied in the case of long passes. Moreover, most of the participants scored lower on decision-making and LSPT after consuming caffeine. This may suggest that more complex tasks with a higher number of passes might negatively be affected by low doses of caffeine ingested one hour before playing soccer. Future studies are required to elucidate the effects of caffeine consumption on distinct cognitive and passing tasks.

Immediate and Long-Term Effects of a Computerized Cognitive Rehabilitation Therapy on Cognitive Function in People Living with HIV in Iran: A Single-Blind Two-Arm Parallel Randomized Controlled Trial

ABSTRACT

Up to 50% of people with HIV (PWH) experience neurocognitive impairments (NCIs) that can interfere with everyday functioning and reduce quality of life. To address this problem, this study examined the immediate and long-term efficacy of computerized cognitive rehabilitation therapy (CCRT) on cognitive function in PWH in Tehran, Iran. Thirty PWH with NCI engaged in 24 biweekly 90-min CCRT sessions. A control group of 30 PWH and NCI received treatment-as-usual, but no CCRT. The cognitive rehabilitation protocol focused on attention, visual memory, nonverbal learning, and planning. Pretest, posttest, and follow-up cognitive measurements showed that the designed CCRT protocol was effective in improving performance in selected cognitive domains along with the global neurocognitive performance scores of PWH. These findings suggest that this CCRT protocol be considered as part of a treatment plan to address cognitive impairment for PWH. Implications for clinical practice and research are provided.

Can I Have My Coffee and Drink It? A Systematic Review and Meta-analysis to Determine Whether Habitual Caffeine Consumption Affects the Ergogenic Effect of Caffeine

OBJECTIVE

The aim was to quantify the proportion of the literature on caffeine supplementation that reports habitual caffeine consumption, and determine the influence of habitual consumption on the acute exercise response to caffeine supplementation, using a systematic review and meta-analytic approach.

METHODS

Three databases were searched, and articles screened according to inclusion/exclusion criteria. Three-level meta-analyses and meta-regression models were used to investigate the influence of habitual caffeine consumption on caffeine's overall ergogenic effect and within different exercise types (endurance, power, strength), in men and women, and in trained and untrained individuals. Sub-analyses were performed according to the following: acute relative dose (< 3, 3-6, > 6 mg/kg body mass [BM]); whether the acute caffeine dose provided was lower or higher than the mean daily caffeine dose; and the caffeine withdrawal period prior to the intervention (< 24, 24-48, > 48 h).

RESULTS

Sixty caffeine studies included sufficient information on habitual consumption to be included in the meta-analysis. A positive overall effect of caffeine was shown in comparison to placebo (standard mean difference [SMD] = 0.25, 95% confidence interval [CI] 0.20-0.30; p < 0.001) with no influence of relative habitual caffeine consumption (p = 0.59). Subgroup analyses showed a significant ergogenic effect when the caffeine dose was < 3 mg/kg BM (SMD = 0.26, 95% CI 0.12-0.40; p = 0.003) and 3-6 mg/kg BM (SMD = 0.26, 95% CI 0.21-0.32; p < 0.0001), but not > 6 mg/kg BM (SMD = 0.11, 95% CI - 0.07 to 0.30; p = 0.23); when the dose was both higher (SMD = 0.26, 95% CI 0.20-0.31; p < 0.001) and lower (SMD = 0.21, 95% CI 0.06-0.36; p = 0.006) than the habitual caffeine dose; and when withdrawal was < 24 h, 24-48 h, and > 48 h. Caffeine was effective for endurance, power, and strength exercise, with no influence (all p ≥ 0.23) of relative habitual caffeine consumption within exercise types. Habitual caffeine consumption did not modify the ergogenic effect of caffeine in male, female, trained or untrained individuals.

CONCLUSION

Habitual caffeine consumption does not appear to influence the acute ergogenic effect of caffeine.

Effects of Nutritional Interventions on Accuracy and Reaction Time with Relevance to Mental Fatigue in Sporting, Military, and Aerospace Populations: A Systematic Review and Meta-Analysis

Background: Research in sport, military, and aerospace populations has shown that mental fatigue may impair cognitive performance. The effect of nutritional interventions that may mitigate such negative effects has been investigated. This systematic review and meta-analysis aimed to quantify the effects of nutritional interventions on cognitive domains often measured in mental fatigue research. Methods: A systematic search for articles was conducted using key terms relevant to mental fatigue in sport, military, and aerospace populations. Two reviewers screened 11,495 abstracts and 125 full texts. A meta-analysis was conducted whereby effect sizes were calculated using subgroups for nutritional intervention and cognitive domains. Results: Fourteen studies were included in the meta-analysis. The consumption of energy drinks was found to have a small positive effect on reaction time, whilst the use of beta-alanine, carbohydrate, and caffeine had no effect. Carbohydrate and caffeine use had no effect on accuracy. Conclusions: The results of this meta-analysis suggest that consuming energy drinks may improve reaction time. The lack of effect observed for other nutritional interventions is likely due to differences in the type, timing, dosage, and form of administration. More rigorous randomized controlled trials related to the effect of nutrition interventions before, during, and after induced mental fatigue are required.

The prevalence and practices of caffeine use as an ergogenic aid in English professional soccer

The ergogenic properties of caffeine are well established, with evidence supporting beneficial effects for physical and technical elements of performance required for successful soccer match play. Despite this, recommended caffeine practices for professional soccer have not been established. Therefore, the present study aimed to evaluate the use and behaviours surrounding caffeine use in elite English soccer clubs. Representatives of 36 clubs from the top four tiers of English professional football (40%) completed an online survey that sought to determine if, when, how and why caffeine was prescribed to players as a means of improving sports performance. Of the clubs sampled, 97% indicated that caffeine is provided to players as a means of improving performance. Caffeine is most commonly administered prior to (> 94%) and during a game (> 48%), with frequency uninfluenced by time of matches. There was a broad range and lack of consistency in the timing, dose and mode of caffeine administration, but doses were typically low. Evidence from the present study indicate a translational gap between science and practice, highlighting a need for future work to better understand how caffeine consumption can be optimised with respect to the specific demands and constraints in professional soccer.

Effects of carbohydrate and caffeine mouth rinsing on strength, muscular endurance and cognitive performance

Background

Carbohydrate (CHO) and caffeine (CAF) mouth rinsing have been shown to enhance endurance and sprint performance. However, the effects of CHO and CAF mouth rinsing on muscular and cognitive performance in comparison between male and female athletes are less well-established. The aim of this study was to examine the effect of CHO and CAF rinsing on squat and bench press 1 repetition maximum (1-RM) strength, 3 sets of 40% of 1-RM muscular endurance and cognitive performance in both male and female athletes.

Methods

Thirteen male and fourteen female resistance-trained participants completed four testing sessions following the rinsing of 25 ml of i) 6% of CHO (1.5 g); ii) 2% CAF (500 mg), iii) combined CHO and CAF (CHOCAF) solutions or iv) water (PLA) for 10 s. Heart rate (HR), felt arousal (FA), ratings of perceived exertion (RPE) and glucose (GLU) were recorded throughout the test protocol.

Results

There were no significant differences in squat and bench press 1-RM, HR, RPE and GLU (p > 0.05) for males and females, respectively. FA was significantly increased with CAF (p = 0.04, p = 0.01) and CHOCAF (p = 0.03, p = 0.01) condition in both males and females, respectively. Squat endurance performance in the first set was significantly increased with CHOCAF condition compared to PLA in both males (p = 0.01) and females (p = 0.02). Bench press endurance was similar for all conditions in both genders (p > 0.05). Cognitive performance was significantly increased with CHOCAF compared to PLA in males (p = 0.03) and females (p = 0.02).

Conclusion

Combined CHO and CAF mouth rinsing significantly improved lower body muscular endurance and cognitive performance in both males and females.

Caffeine and Cognitive Functions in Sports: A Systematic Review and Meta-Analysis

Cognitive functions are essential in any form of exercise. Recently, interest has mounted in addressing the relationship between caffeine intake and cognitive performance during sports practice. This review examines this relationship through a structured search of the databases Medline/PubMed and Web of Science for relevant articles published in English from August 1999 to March 2020. The study followed PRISMA guidelines. Inclusion criteria were defined according to the PICOS model. The identified records reported on randomized cross-over studies in which caffeine intake (as drinks, capsules, energy bars, or gum) was compared to an identical placebo situation. There were no filters on participants’ training level, gender, or age. For the systematic review, 13 studies examining the impacts of caffeine on objective measures of cognitive performance or self-reported cognitive performance were selected. Five of these studies were also subjected to meta-analysis. After pooling data in the meta-analysis, the significant impacts of caffeine only emerged on attention, accuracy, and speed. The results of the 13 studies, nevertheless, suggest that the intake of a low/moderate dose of caffeine before and/or during exercise can improve self-reported energy, mood, and cognitive functions, such as attention; it may also improve simple reaction time, choice reaction time, memory, or fatigue, however, this may depend on the research protocols.

Similar ergogenic effect of caffeine on anaerobic performance in men and women athletes

PURPOSE

Caffeine is widely considered an ergogenic aid to increase anaerobic performance although most of this evidence is supported by investigations with only male samples. To date, it is unknown if the ergogenic effect of caffeine on anaerobic performance is of similar magnitude in men and women athletes. The aim of this study was to determine the magnitude of the ergogenic effect of caffeine on the Wingate test in men and women.

METHODS

In a double-blind, placebo-controlled, cross-over experimental trial, ten women athletes and ten men athletes performed a 15-s adapted version of the Wingate test after ingesting 3 mg of caffeine per kg of body mass or a placebo (cellulose).

RESULTS

In comparison to the performance obtained in the 15-s Wingate test with a placebo, caffeine increased peak power in men (9.9 ± 0.8 vs. 10.1 ± 0.8 W/kg, p < 0.01, d = 0.26) and in women (8.8 ± 0.9 vs. 9.1 ± 0.8 W/kg, p = 0.04, d = 0.30). Caffeine was also effective to increase the mean power in men (8.9 ± 0.7 vs. 9.0 ± 0.7 W/kg, p = 0.01, d = 0.21) and women (8.1 ± 0.7 vs. 8.3 ± 0.7 W/kg, p = 0.01, d = 0.27). The ergogenic effect of caffeine on the 15-s Wingate peak power (2.3 ± 3.2% in men and 3.2 ± 2.8% in women; p = 0.46) and mean power (2.0 ± 1.7% and 2.4 ± 2.3%, respectively; p = 0.93) was of similar magnitude in both sexes.

CONCLUSION

Acute ingestion of 3 mg kg^-1 of caffeine enhanced peak and mean cycling power during a 15-s adapted version of the Wingate test in men and women and the ergogenic effect was of similar magnitude in both sexes. This information suggests that both men and women athletes might obtain similar benefits from caffeine supplementation during anaerobic exercise.

International society of sports nutrition position stand: caffeine and exercise performance

Following critical evaluation of the available literature to date, The International Society of Sports Nutrition (ISSN) position regarding caffeine intake is as follows: 1. Supplementation with caffeine has been shown to acutely enhance various aspects of exercise performance in many but not all studies. Small to moderate benefits of caffeine use include, but are not limited to: muscular endurance, movement velocity and muscular strength, sprinting, jumping, and throwing performance, as well as a wide range of aerobic and anaerobic sport-specific actions. 2. Aerobic endurance appears to be the form of exercise with the most consistent moderate-to-large benefits from caffeine use, although the magnitude of its effects differs between individuals. 3. Caffeine has consistently been shown to improve exercise performance when consumed in doses of 3-6 mg/kg body mass. Minimal effective doses of caffeine currently remain unclear but they may be as low as 2 mg/kg body mass. Very high doses of caffeine (e.g. 9 mg/kg) are associated with a high incidence of side-effects and do not seem to be required to elicit an ergogenic effect. 4. The most commonly used timing of caffeine supplementation is 60 min pre-exercise. Optimal timing of caffeine ingestion likely depends on the source of caffeine. For example, as compared to caffeine capsules, caffeine chewing gums may require a shorter waiting time from consumption to the start of the exercise session. 5. Caffeine appears to improve physical performance in both trained and untrained individuals. 6. Inter-individual differences in sport and exercise performance as well as adverse effects on sleep or feelings of anxiety following caffeine ingestion may be attributed to genetic variation associated with caffeine metabolism, and physical and psychological response. Other factors such as habitual caffeine intake also may play a role in between-individual response variation. 7. Caffeine has been shown to be ergogenic for cognitive function, including attention and vigilance, in most individuals. 8. Caffeine may improve cognitive and physical performance in some individuals under conditions of sleep deprivation. 9. The use of caffeine in conjunction with endurance exercise in the heat and at altitude is well supported when dosages range from 3 to 6 mg/kg and 4-6 mg/kg, respectively. 10. Alternative sources of caffeine such as caffeinated chewing gum, mouth rinses, energy gels and chews have been shown to improve performance, primarily in aerobic exercise. 11. Energy drinks and pre-workout supplements containing caffeine have been demonstrated to enhance both anaerobic and aerobic performance.

Effects of Different Doses of Caffeinated Coffee on Muscular Endurance, Cognitive Performance, and Cardiac Autonomic Modulation in Caffeine Naive Female Athletes

Caffeine is widely consumed among elite athletes for its well-known ergogenic properties, and its ability to increase exercise performance. However, studies to date have predominantly focused on the anhydrous form of caffeine in male participants. The aim of the study was to investigate the effect of caffeinated coffee ingestion on lower-upper body muscular endurance, cognitive performance, and heart rate variability (HRV) in female athletes. A total of 17 participants (mean ± standard deviation (SD): age = 23 ± 2 years, body mass = 64 ± 4 kg, height = 168 ± 3 cm) in a randomized cross-over design completed three testing sessions, following the ingestion of 3 mg/kg/bm of caffeine (3COF), 6 mg/kg/bm of caffeine (6COF) provided from coffee or decaffeinated coffee (PLA) in 600 mL of hot water. The testing results included: (1) repetition number for muscular endurance performance; (2): reaction time and response accuracy for cognitive performance; (3): HRV parameters, such as standard deviation of normal-to-normal (NN) intervals (SDNN), standard deviation of successive differences (SDSD), root mean square of successive differences (RMSSD), total power (TP), the ratio of low- and high-frequency powers (LF/HF), high-frequency power (HF), normalized HF (HFnu), low-frequency power (LF), and normalized LF (LFnu). A one-way repeated measures ANOVA revealed that 3COF (p = 0.024) and 6COF (p = 0.036) improved lower body muscular endurance in the first set as well as cognitive performance (p = 0.025, p = 0.035 in the post-test, respectively) compared to PLA. However, no differences were detected between trials for upper body muscular endurance (p = 0.07). Lastly, all HRV parameters did not change between trials (p > 0.05). In conclusion, ingesting caffeinated coffee improved lower body muscular endurance and cognitive performance, while not adversely affecting cardiac autonomic function.

The Effect of Acute Caffeine Ingestion on Cognitive Dual Task Performance during Assessment of Static and Dynamic Balance in Older Adults

The present work aimed to evaluate the effect of 3 mg·kg⁻¹ caffeine consumption on the standing and dynamic balance performance of older adults and sought to establish if caffeine ingestion can modulate the influence of a cognitive dual task on balance performance. Twelve apparently healthy participants (8 females) aged >65 years (72 ± 3.7 years) completed the study. Bipedal postural sway, four square step test, timed up and go, Y-balance (anterior reach only) and force-time characteristics of sit-to-stand performance were used to assess standing and dynamic balance. Attention and working memory were assessed using a serial 3s and 7s subtraction task during seated rest and completion of the bipedal standing assessment and Y-balance test. This battery of assessments was completed on two separate occasions, once following the consumption of a non-ergogenic placebo and again following the consumption of 3 mg·kg⁻¹ caffeine. The administration of treatments was randomised, counterbalanced and double-blind. Caffeine reduced performance in the bipedal standing balance assessments, evidenced by an increase in COP_ML, COP_Path, COP_Velocity. Performance during the dynamic balance tests was unaffected, other than rate of force development during the sit-to-stand, which was improved following caffeine ingestion. The introduction of a cognitive dual task had either limited effects, or improved facets of bipedal standing balance, whilst performance during the dynamic balance task was significantly reduced. In both balance assessments, there was evidence for a reduction in the performance of the cognitive task when both the balance and cognitive tests were performed simultaneously, with this effect not modulated by caffeine consumption. These findings refute the idea that caffeine ingestion may have positive effects on balance performance. However, despite a caffeine-induced reduction in bipedal standing balance, it is unlikely that caffeine ingestion would exacerbate fall risk given the limited effects in the dynamic balance tests. Future work should establish if these effects are generalisable to older frail participants and if caffeine can modulate the detrimental effects of an acute exercise bout on balance performance.

Effects of a Multi-Ingredient Preworkout Supplement Versus Caffeine on Energy Expenditure and Feelings of Fatigue during Low-Intensity Treadmill Exercise in College-Aged Males

The primary purpose of this study was to examine the acute effects of a multi-ingredient (i.e., caffeine, green tea extract, Yohimbe extract, capsicum annum, coleus extract, L-carnitine, beta-alanine, tyrosine) preworkout supplement versus a dose of caffeine (6 mg·kg⁻¹) on energy expenditure during low-intensity exercise. The effects of these treatments on substrate utilization, gas exchange, and psychological factors were also investigated. Twelve males (mean ± SD: age = 22.8 ± 2.4 years) completed three bouts of 60 min of treadmill exercise on separate days after consuming a preworkout supplement, 6 mg·kg⁻¹ of caffeine, or placebo in a randomized fashion. The preworkout and caffeine supplements resulted in significantly greater energy expenditure (p < 0.001, p = 0.006, respectively), V˙O₂ (p < 0.001, p = 0.007, respectively), V˙CO₂ (p = 0.006, p = 0.049, respectively), and V˙_E (p < 0.001, p = 0.007, respectively) compared to placebo (collapsed across condition). There were no differences among conditions, however, for rates of fat or carbohydrate oxidation or respiratory exchange ratio. In addition, the preworkout supplement increased feelings of alertness (p = 0.015) and focus (p = 0.005) 30-min postingestion and decreased feelings of fatigue (p = 0.014) during exercise compared to placebo. Thus, the preworkout supplement increased energy expenditure and measures of gas exchange to the same extent as 6 mg·kg⁻¹ of caffeine with concomitant increased feelings of alertness and focus and decreased feelings of fatigue.

Neuronal adenosine A2A receptors signal ergogenic effects of caffeine

Caffeine is one of the most used ergogenic aid for physical exercise and sports. However, its mechanism of action is still controversial. The adenosinergic hypothesis is promising due to the pharmacology of caffeine, a nonselective antagonist of adenosine A1 and A2A receptors. We now investigated A2AR as a possible ergogenic mechanism through pharmacological and genetic inactivation. Forty-two adult females (20.0 ± 0.2 g) and 40 male mice (23.9 ± 0.4 g) from a global and forebrain A2AR knockout (KO) colony ran an incremental exercise test with indirect calorimetry (V̇O2 and RER). We administered caffeine (15 mg/kg, i.p., nonselective) and SCH 58261 (1 mg/kg, i.p., selective A2AR antagonist) 15 min before the open field and exercise tests. We also evaluated the estrous cycle and infrared temperature immediately at the end of the exercise test. Caffeine and SCH 58621 were psychostimulant. Moreover, Caffeine and SCH 58621 were ergogenic, that is, they increased V̇O2max, running power, and critical power, showing that A2AR antagonism is ergogenic. Furthermore, the ergogenic effects of caffeine were abrogated in global and forebrain A2AR KO mice, showing that the antagonism of A2AR in forebrain neurons is responsible for the ergogenic action of caffeine. Furthermore, caffeine modified the exercising metabolism in an A2AR-dependent manner, and A2AR was paramount for exercise thermoregulation.

Effects of One Versus Two Doses of a Multi-Ingredient Pre-Workout Supplement on Metabolic Factors and Perceived Exertion during Moderate-Intensity Running in Females

The primary purpose of this study was to examine the acute effects of one versus two doses of a multi-ingredient pre-workout supplement on energy expenditure during moderate-intensity treadmill running. In addition, our second aim was to investigate the responses of associated metabolic factors (i.e., substrate utilization, measures of gas exchange), perceived exertion, and resting cardiovascular variables with one and two doses of the pre-workout supplement. Twelve females (mean ± SD: age = 25.3 ± 9.4 years; body mass = 61.2 ± 6.8 kg) completed three bouts of 30 min of treadmill running at 90% of their ventilatory threshold on separate days after consuming one dose of the pre-workout supplement (1-dose), two doses (2-dose), and a placebo. There were no differences among conditions for energy expenditure, fat or carbohydrate oxidation, respiratory exchange ratio, oxygen consumption, or heart rate across exercise time. The two-dose group, however, had lower (p = 0.036) ratings of perceived exertion (11.8 ± 1.7) than the one-dose (12.6 ± 1.7) and the placebo (12.3 ± 1.2) at the 20-min time point of exercise as well as greater resting systolic blood pressure (110 ± 10 mmHg) compared to the one-dose (106 ± 10 mmHg) and the placebo (104 ± 10 mmHg) conditions. Both the one-dose and two-dose conditions had greater increases in diastolic blood pressure compared to the placebo. Thus, our findings indicated that the present pre-workout supplement had no performance-enhancing benefits related to energy metabolism but did attenuate feelings of exertion.

Acute caffeine intake increases performance in the 15-s Wingate test during the menstrual cycle

AIMS

In male athletes, caffeine is considered an ergogenic aid to increase anaerobic performance during the Wingate anaerobic test (WANT). However, information about the effect of caffeine on WANT performance in female athletes is contradictory. Furthermore, it is unknown whether the ergogenicity of caffeine is present during all the phases of the menstrual cycle. The aim of this study was to investigate the effects of caffeine intake on WANT performance during 3 phases of the menstrual cycle.

METHODS

Thirteen well-trained eumenorrhoeic triathletes participated in a double-blind, placebo-controlled, cross-over experimental trial. On 2 different days in each phase, and in randomized order, participants ingested caffeine (3 mg kg-1 ) or a placebo (cellulose). The menstrual cycle phases were individually characterized as follows: (i) early follicular; (ii) preovulatory; and (iii) midluteal. In each trial, participants performed a 15-s adapted version of the WANT.

RESULTS

In comparison to the placebo, caffeine increased peak power during the WANT in the early follicular (8.6 ± 0.8 vs 8.9 ± 0.9 W/kg, P = .04; effect size [d] = 0.45), preovulatory (8.6 ± 0.9 vs 8.9 ± 0.9 W/kg, P = .04; d = 0.23) and mid-luteal phases (8.6 ± 0.8 vs 8.9 ± 0.9 W/kg, P < .01; d = 0.52).

CONCLUSION

The ergogenic effect of caffeine on WANT peak cycling power was of a similar magnitude in the follicular, preovulatory, and mid-luteal phases. These results suggest that caffeine increases performance in the 15-s Wingate test in women athletes and it might be considered an ergogenic aid to increase anaerobic performance in eumenorrhoeic women during their menstrual cycle.

Effects of caffeine supplementation on physical performance and mood dimensions in elite and trained-recreational athletes

BACKGROUND

Caffeine supplementation (CAFF) has an established ergogenic effect on physical performance and the psychological response to exercise. However, few studies have compared the response to CAFF intake among athletes of different competition level. This study compares the acute effects of CAFF on anaerobic performance, mood and perceived effort in elite and moderately-trained recreational athletes.

METHODS

Participants for this randomized, controlled, crossover study were 8 elite athletes (in the senior boxing national team) and 10 trained-recreational athletes. Under two experimental conditions, CAFF supplementation (6 mg/kg) or placebo (PLAC), the athletes completed a Wingate test. Subjective exertion during the test was recorded as the rating of perceived exertion (RPE) both at the general level (RPEgeneral) and at the levels muscular (RPEmuscular) and cardiorespiratory (RPEcardio). Before the Wingate test, participants completed the questionnaires Profiles of Moods States (POMS) and Subjective Vitality Scale (SVS).

RESULTS

In response to CAFF intake, improvements were noted in Wpeak (11.22 ± 0.65 vs 10.70 ± 0.84; p = 0.003; [Formula: see text] =0.44), Wavg (8.75 ± 0.55 vs 8.41 0.46; p = 0.001; [Formula: see text] =0.53) and time taken to reach Wpeak (7.56 ± 1.58 vs 9.11 ± 1.53; p <  0.001; [Formula: see text] =0.57) both in the elite and trained-recreational athletes. However, only the elite athletes showed significant increases in tension (+ 325%), vigor (+ 31%) and SVS (+ 28%) scores after the intake of CAFF compared to levels recorded under the condition PLAC (p <  0.05). Similarly, levels of vigor after consuming CAFF were significantly higher in the elite than the trained-recreational athletes (+ 5.8%).

CONCLUSIONS

CAFF supplementation improved anaerobic performance in both the elite and recreational athletes. However, the ergogenic effect of CAFF on several mood dimensions and subjective vitality was greater in the elite athletes.

Exercise intensity-dependent effects of arm and leg-cycling on cognitive performance

Physiological responses to arm and leg-cycling are different, which may influence psychological and biological mechanisms that influence post-exercise cognitive performance. The aim of this study was to determine the effects of maximal and submaximal (absolute and relative intensity matched) arm and leg-cycling on executive function. Thirteen males (age, 24.7 ± 5.0 years) initially undertook two incremental exercise tests to volitional exhaustion for arm-cycling (82 ± 18 W) and leg-cycling (243 ± 52 W) for the determination of maximal power output. Participants subsequently performed three 20-min constant load exercise trials: (1) arm-cycling at 50% of the ergometer-specific maximal power output (41 ± 9 W), (2) leg-cycling at 50% of the ergometer-specific maximal power output (122 ± 26 W), and (3) leg-cycling at the same absolute power output as the submaximal arm-cycling trial (41 ± 9 W). An executive function task was completed before, immediately after and 15-min after each exercise test. Exhaustive leg-cycling increased reaction time (p < 0.05, d = 1.17), while reaction time reduced following exhaustive arm-cycling (p < 0.05, d = -0.62). Improvements in reaction time were found after acute relative intensity arm (p < 0.05, d = -0.76) and leg-cycling (p < 0.05, d = -0.73), but not following leg-cycling at the same absolute intensity as arm-cycling (p > 0.05). Improvements in reaction time following arm-cycling were maintained for at least 15-min post exercise (p = 0.008, d = -0.73). Arm and leg-cycling performed at the same relative intensity elicit comparable improvements in cognitive performance. These findings suggest that individuals restricted to arm exercise possess a similar capacity to elicit an exercise-induced cognitive performance benefit.

The effect of acute caffeine ingestion on upper and lower body anaerobic exercise performance

The current study examined the effect of acute caffeine ingestion on mean and peak power production, fatigue index and rating of perceived exertion (RPE) during upper body and lower body Wingate anaerobic test (WANT) performance. Using a double-blind design, 22 males undertook one upper body and one lower body WANT, 60 min following ingestion of caffeine (5 mg*kg^-1) and one upper body and one lower body WANT following ingestion of placebo (5 mg*kg^-1 Dextrose). Peak power was significantly higher (P = .001) following caffeine ingestion in both upper and lower body WANT. Peak power and mean power was also significantly higher during lower body, compared to upper body WANTs irrespective of substance ingested. However, caffeine ingestion did not enhance mean power neither in upper nor lower-body WANT. There were no significant differences in mean fatigue index as a consequence of substance ingested or mode of exercise (all P > 0.05). For RPE there was also a significant substance ingested X mode interaction (P = .001) where there were no differences in RPE between caffeine and placebo conditions in lower body WANTs but significantly lower RPE during upper body WANT in the presence of caffeine compared to placebo (P = .014). This is the first study to compare the effects of caffeine ingestion on upper and lower body 30-second WANT performance and suggests that caffeine ingestion in the dose of 5 mg*kg^-1 ingested 60 min prior to exercise significantly enhances peak power when data from upper and lower body WANTs are combined.