Journal Article•
Caffeine Alters Blood Potassium and Catecholamine Concentrations but not the Perception of Pain and Fatigue with a 1 km Cycling Sprint
TL;DR: The results suggest that caffeine can enhance certain metabolic parameters, but these changes were unable to augment short-distance (1km), high-intensity cycling performance.
Abstract: Background: Caffeine has been used by some athletes to improve short-term high-intensity exercise performance; however, the literature is equivocal. Objectives: The objective of this study was to investigate the effects of caffeine on plasma potassium and catecholamine concentrations, pain and fatigue perception, to determine whether potassium ion handling and altered perception related to the central nervous system are associated with enhanced performance during a 1 km cycling time trial. Methods: Thirteen well trained men with a mean age of 27 ± 6 yrs (body mass: 76.4 ± 6.4 kg, height: 180 ± 7 cm, and max: 57.5 ± 4.6 ml·kg -1 ·min -1 ) were recruited. Participants were randomized to a caffeine (5 mg·kg -1 ) or a placebo condition using a double blind, cross over design. Results: Caffeine had no significant effects on the 1 km time-trial performance indicators of time (82.1 ± 2.4 vs. 81.9 ± 3.9s), peak (633.0 ± 83.6 vs. 638.7 ± 110.1 watts) or average power (466.0 ± 37.3 vs. 467.5 ± 59.9 watts; caffeine and placebo conditions respectively). In addition, caffeine had no significant effect on oxygen consumption () (4.11 ± 0.24 vs 4.06 ± 0.29 L),the perception of pain (5.6 ± 2.4 vs. 5.5 ± 2.6) or fatigue (7.1 ± 1.8 vs.7.1 ± 1.8: caffeine and placebo conditions respectively). There was a significantly greater increase in post-exercise blood lactate (p<0.05) and catecholamines (p<0.05) as well as a lower pre-exercise blood potassium concentration (p<0.05) in the caffeine condition. Conclusions: The results suggest that caffeine can enhance certain metabolic parameters, but these changes were unable to augment short-distance (1km), high-intensity cycling performance. Keywords: ergogenic, anaerobic exercise, performance, oxygen consumption
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TL;DR: Caffeine and bicarbonate's ergogenic effect is clearly documented for intense endurance performance and for all supplements an individualized approach may improve the ergogenicEffect on performance.
Abstract: A 1% change in average speed is enough to affect medal rankings in intense Olympic endurance events lasting ~45 s to 8 min which for example includes 100-m swimming and 400-m running (~1 min), 1500-m running and 4000-m track cycling (~4 min) and 2000 m rowing (~6-8 min). To maximize the likelihood of winning, athletes utilizes legal supplements with or without scientifically documented beneficial effects on performance. Therefore, a continued systematic evidence based evaluation of the possible ergogenic effects is of high importance. A meta-analysis was conducted with a strict focus on closed-end performance tests in humans in the time domain from 45 s to 8 min. These test include time-trials or total work done in a given time. This selection criterion results in a high relevance for athletic performance. Only peer-reviewed placebo controlled studies were included. The often applied and potentially ergogenic supplements beta-alanine, bicarbonate, caffeine and nitrate were selected for analysis. Following a systematic search in Pubmed and SportsDiscuss combined with evaluation of cross references a total of 7 (beta-alanine), 25 (bicarbonate), 9 (caffeine) and 5 (nitrate) studies was included in the meta-analysis. For each study, performance was converted to an average speed (km/h) from which an effect size (ES; Cohens d with 95% confidence intervals) was calculated. A small effect and significant performance improvement relative to placebo was observed for caffeine (ES: 0.41 [0.15 – 0.68], P=0.002) and bicarbonate (ES: 0.40 [0.27 – 0.54], P<0.001). Trivial and non-significant effects on performance was observed for nitrate (ES: 0.19 [-0.03 – 0.40], P=0.09) and (ES: 0.17 [-0.12 – 0.46], P=0.24). Thus, caffeine’s and bicarbonate´s ergogenic effect is clearly documented for intense endurance performance. Importantly, for all supplements an individualized approach may improve the effect on performance.
68 citations
Cites background from "Caffeine Alters Blood Potassium and..."
...…studies has been published showing no effect on intense endurance performance from both bicarbonate (Callahan et al., 2016) and nitrate (Callahan et al., 2016) supplementation whereas caffeine has resulted in both unchanged (Cordingley et al., 2016) and improved performance (Boyett et al., 2016)....
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TL;DR: The findings of this study do not show a significant correlation between CAF ingestion and improved anaerobic performance in experienced cyclists, however, performance enhancements may depend on varying individual responses to CAF.
Abstract: Anderson, DE, LeGrand, SE, and McCart, RD. Effect of caffeine on sprint cycling in experienced cyclists. J Strength Cond Res 32(8): 2221-2226, 2018-Research regarding the ergogenic effects of caffeine (CAF) in anaerobic activity remains inconclusive. However, some researchers have found significant improvements in anaerobic performance when testing specifically trained athletes. A double-blind, placebo-controlled, counterbalanced, cross-over design was implemented to assess the impact of CAF on a 30-second Wingate Anaerobic Test (WAnT) in experienced cyclists. Nine experienced cyclists volunteered to participate in this study (men, n = 7 and women, n = 2). The subjects completed 2 separate experimental trials consisting of a 30-second WAnT at a resistance of 9% body mass. In a random order, 1 hour before each WAnT, subjects ingested either a CAF (∼280 mg) or placebo (PLAC) coffee. For each trial, heart rate (HR) and blood lactate (BL) values were recorded at rest, pre-WAnT, post-WAnT, and 5 minutes post-WAnT. After each trial, the subjects recorded their perception of which treatment they received. Heart rate and BL responses were not significantly different between the CAF and PLAC conditions. The ingestion of CAF did not significantly improve peak anaerobic power, mean anaerobic power, nor fatigue index. In at least 1 of the 2 trials, 44% of the subjects incorrectly guessed which substance they had ingested. The findings of this study do not show a significant correlation between CAF ingestion and improved anaerobic performance in experienced cyclists. However, performance enhancements may depend on varying individual responses to CAF. Athletes who are positive CAF responders may consider using coffee before competition to improve anaerobic performance.
11 citations
TL;DR: Assessment of the acute effects of caffeinated chewing gum on bicycle motocross (BMX) time-trial (TT) performance revealed that Administering a moderate dose of CAF could improve TT time by enhancing power and reducing the perception of exertion.
Abstract: This study aimed to identify the acute effects of caffeinated chewing gum (CAF) on bicycle motocross (BMX) time-trial (TT) performance. In a randomized, placebo-controlled, double-blind cross-over design, 14 male BMX riders (age = 20.0 ± 3.3 years; height = 1.78 ± 0.04 m; body mass = 72 ± 4 kg), consumed either (300 mg; 4.2 ± 0.2 mg/kg) caffeinated (300 mg caffeine, 6 g sugars) or a placebo (0 mg caffeine, 0 g sugars) gum, and undertook three BMX TTs. Repeated-measure analysis revealed that CAF has a large ergogenic effect on TT time, F(1, 14) = 33.570, p = .001, η2p=.71; −1.5% ± 0.4 compared with the placebo. Peak power and maximal power to weight ratio also increased significantly compared with the placebo condition, F(1, 14) = 54.666, p = .001, η2p=.79; +3.5% ± 0.6, and F(1, 14) = 57.399, p = .001, η2p=.80; +3% ± 0.3, respectively. Rating of perceived exertion was significantly lower F(1, 14) = 25.020, p = .001, η2p=.64 in CAF (6.6 ± 1.3) compared with the placebo (7.2 ± 1.7). Administering a moderate dose (300 mg) of CAF could improve TT time by enhancing power and reducing the perception of exertion. BMX coaches and riders may consider consuming CAF before a BMX race to improve performance and reduce rating of perceived exertion.
3 citations
01 Jan 2018
TL;DR: It is demonstrated that consuming a moderate dose of caffeine enhances exercise performance and increases ventilatory work without altering RPB.
Abstract: Caffeine (CAF) is commonly ingested as an ergogenic aid among cyclists, in part, due to its effect on pain perception. CAF may improve performance by altering the perceptions related to ventilatory work and dyspnea. The purpose of this study was to evaluate exercise performance and breathlessness in cyclists during a fixed-work time trial (TT) after the ingestion of caffeine. Nine male cyclists completed pulmonary function testing and a peak aerobic capacity test (V?O2peak: 60.8±5.7 ml·kg-1·min-1). During visit two, cyclists completed a fixed-work familiarization TT equivalent to a distance of 20-km. Subsequently, subjects completed in a randomized, counterbalanced order, TTs with ingestion of a placebo (TTPLA) or caffeine (TTCAF; 5 mg·kg-1). Elapsed time was significantly reduced during TTCAF compared with TTPLA (33.5±2.8 vs. 35.5±2.7 min, p < 0.01). RPB did not differ between TTCAF and TTPLA at any interval (p = 0.755). A main effect was observed in ventilation during TTCAF when compared with TTPLA (p = 0.019). A main effect was observed in integrated inspiratory mouth pressure during TTCAF when compared with TTPLA (p = 0.040). These results demonstrate that consuming a moderate dose of caffeine enhances exercise performance and increases ventilatory work without altering RPB.
2 citations
Cites background from "Caffeine Alters Blood Potassium and..."
...Contrarily, there are published reports indicating that caffeine does not alter RPE or leg pain during exhaustive exercise (Astorino et al., 2012c; Cordingley et al., 2016)....
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References
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TL;DR: Historically, the achievement of maximal oxygen uptake (VO2max) has been based on objective criteria such as a leveling off of oxygen uptake with an increase in work rate, high levels of lactic acid in the blood in the minutes following the exercise test, and achievement of some percentage of an age-adjusted estimate of maximal heart rate.
Abstract: Historically, the achievement of maximal oxygen uptake (O2max) has been based on objective criteria such as a leveling off of oxygen uptake with an increase in work rate, high levels of lactic acid in the blood in the minutes following the exercise test, elevated respiratory exchange ratio,
1,645 citations
"Caffeine Alters Blood Potassium and..." refers background in this paper
...…peak and plateau in oxygen uptake ( 100mL/min) with increasing power output or duration of exercise that was also associated with secondary criteria including a respiratory exchange ratio (RER) greater than 1.1, a heart rate ≥ age-predicted maximum and volitional exhaustion (Howley et al., 1995)....
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...1, a heart rate ≥ age-predicted maximum and volitional exhaustion (Howley et al., 1995)....
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TL;DR: A visual analogue scale to evaluate fatigue severity (VAS-F) was developed and tested and demonstrated significant differences between their evening and morning scores, while sleep-disordered patients did not.
Abstract: A visual analogue scale to evaluate fatigue severity (VAS-F) was developed and tested in a sample of 75 healthy individuals and a sample of 57 patients undergoing medical evaluation for sleep disorders. The scale consists of 18 items related to fatigue and energy, has simple instructions, and is completed with minimal time and effort. The VAS-F compares favorably with the Stanford Sleepiness Scale and the Profile of Mood States, and its internal consistency reliabilities are high. Healthy subjects demonstrated significant differences between their evening and morning scores on the VAS-F, while sleep-disordered patients did not.
1,002 citations
TL;DR: The limited information available suggests that caffeine non-users and users respond similarly and that withdrawal from caffeine may not be important, and caffeine may act synergistically with other drugs including ephedrine and anti-inflammatory agents.
Abstract: Caffeine is a common substance in the diets of most athletes and it is now appearing in many new products, including energy drinks, sport gels, alcoholic beverages and diet aids. It can be a powerful ergogenic aid at levels that are considerably lower than the acceptable limit of the International Olympic Committee and could be beneficial in training and in competition. Caffeine does not improve maximal oxygen capacity directly, but could permit the athlete to train at a greater power output and/or to train longer. It has also ben shown to increase speed and/or power output in simulated race conditions. These effects have been found in activities that last as little as 60 seconds or as long as 2 hours. There is less information about the effects of caffeine on strength; however, recent work suggests no effect on maximal ability, but enhanced endurance or resistance to fatigue. There is no evidence that caffeine ingestion before exercise leads to dehydration, ion imbalance, or any other adverse effects. The ingestion of caffeine as coffee appears to be ineffective compared to doping with pure caffeine. Related compounds such as theophylline are also potent ergogenic aids. Caffeine may act synergistically with other drugs including ephedrine and anti-inflammatory agents. It appears that male and female athletes have similar caffeine pharmacokinetics, i.e., for a given dose of caffeine, the time course and absolute plasma concentrations of caffeine and its metabolites are the same. In addition, exercise or dehydration does not affect caffeine pharmacokinetics. The limited information available suggests that caffeine non-users and users respond similarly and that withdrawal from caffeine may not be important. The mechanism(s) by which caffeine elicits its ergogenic effects are unknown, but the popular theory that it enhances fat oxidation and spares muscle glycogen has very little support and is an incomplete explanation at best. Caffeine may work, in part, by creating a more favourable intracellular ionic environment in active muscle. This could facilitate force production by each motor unit.
760 citations
"Caffeine Alters Blood Potassium and..." refers background or methods or result in this paper
...…support previous studies, which found caffeine to increase post-exercise lactate concentrations greater than placebo (Anselme et al., 1992; Bridge & Jones, 2006; Collomp et al., 1992; Cox et al., 2002; Davis & Green, 2009; Graham, 2001; Graham et al., 1998; Greer et al., 1998; Ivy et al., 2009)....
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...…a randomly assigned treatment of either a flavored, non-caloric placebo drink (500 ml of water with Crystal Light, Kraft Canada) or caffeine (Life Brand, Shoppers Drug Mart, Canada) at a serving of 5 mg∙kg-1 body mass (Graham, 2001) dissolved in 500 ml of the same flavored drink as the placebo....
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...The increase in blood lactate may be due to caffeine inhibiting lactate clearance (Graham, 2001), or catecholamines stimulating glycolysis (Cheetham et al....
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...These results support previous studies, which found caffeine to increase post-exercise lactate concentrations greater than placebo (Anselme et al., 1992; Bridge & Jones, 2006; Collomp et al., 1992; Cox et al., 2002; Davis & Green, 2009; Graham, 2001; Graham et al., 1998; Greer et al., 1998; Ivy et al., 2009)....
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...Each subject then consumed a randomly assigned treatment of either a flavored, non-caloric placebo drink (500 ml of water with Crystal Light, Kraft Canada) or caffeine (Life Brand, Shoppers Drug Mart, Canada) at a serving of 5 mg∙kg body mass (Graham, 2001) dissolved in 500 ml of the same flavored drink as the placebo....
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TL;DR: Higher capacity to secrete adrenaline was observed both in response to physical exercise and to other stimuli such as hypoglycaemia and hypoxia, and this phenomenon can partly explain the higher physical performance observed in trained compared with untrained subjects.
Abstract: Stress hormones, adrenaline (epinephrine) and noradrenaline (norepinephrine), are responsible for many adaptations both at rest and during exercise. Since their discovery, thousands of studies have focused on these two catecholamines and their importance in many adaptive processes to different stressors such as exercise, hypoglycaemia, hypoxia and heat exposure, and these studies are now well acknowledged. In fact, since adrenaline and noradrenaline are the main hormones whose concentrations increase markedly during exercise, many researchers have worked on the effect of exercise on these amines and reported 1.5 to >20 times basal concentrations depending on exercise characteristics (e.g. duration and intensity). Similarly, several studies have shown that adrenaline and noradrenaline are involved in cardiovascular and respiratory adjustments and in substrate mobilization and utilization. Thus, many studies have focused on physical training and gender effects on catecholamine response to exercise in an effort to verify if significant differences in catecholamine responses to exercise could be partly responsible for the different performances observed between trained and untrained subjects and/or men and women. In fact, previous studies conducted in men have used different types of exercise to compare trained and untrained subjects in response to exercise at the same absolute or relative intensity. Their results were conflicting for a while. As research progressed, parameters such as age, nutritional and emotional state have been found to influence catecholamine concentrations. As a result, most of the recent studies have taken into account all these parameters. Those studies also used very well trained subjects and/or more intense exercise, which is known to have a greater effect on catecholamine response so that differences between trained and untrained subjects are more likely to appear. Most findings then reported a higher adrenaline response to exercise in endurance-trained compared with untrained subjects in response to intense exercise at the same relative intensity as all-out exercise. This phenomenon is referred to as the 'sports adrenal medulla'. This higher capacity to secrete adrenaline was observed both in response to physical exercise and to other stimuli such as hypoglycaemia and hypoxia. For some authors, this phenomenon can partly explain the higher physical performance observed in trained compared with untrained subjects. More recently, these findings have also been reported in anaerobic-trained subjects in response to supramaximal exercise. In women, studies remain scarce; the results are more conflicting than in men and the physical training type (aerobic or anaerobic) effects on catecholamine response remain to be specified. Conversely, the works undertaken in animals are more unanimous and suggest that physical training can increase the capacity to secrete adrenaline via an increase of the adrenal gland volume and adrenaline content.
411 citations
"Caffeine Alters Blood Potassium and..." refers result in this paper
...These findings were consistent with the results of (Zouhal et al., 2008), who reported an increase in catecholamine concentrations with exercise that were closely related to intensity....
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TL;DR: The available literature that follows guidelines suggests that performance benefits can be seen with moderate amounts of caffeine, and these benefits are likely to occur across a range of sports, including endurance events, stop-and-go events, and sports involving sustained high-intensity activity lasting from 1-60 min.
Abstract: Athletes are among the groups of people who are interested in the effects of caffeine on endurance and exercise capacity. Although many studies have investigated the effect of caffeine ingestion on exercise, not all are suited to draw conclusions regarding caffeine and sports performance. Characteristics of studies that can better explore the issues of athletes include the use of well-trained subjects, conditions that reflect actual practices in sport, and exercise protocols that simulate real-life events. There is a scarcity of field-based studies and investigations involving elite performers. Researchers are encouraged to use statistical analyses that consider the magnitude of changes, and to establish whether these are meaningful to the outcome of sport. The available literature that follows such guidelines suggests that performance benefits can be seen with moderate amounts (~3 mg.kg-1 body mass) of caffeine. Furthermore, these benefits are likely to occur across a range of sports, including endurance events, stop-and-go events (e.g., team and racquet sports), and sports involving sustained high-intensity activity lasting from 1-60 min (e.g., swimming, rowing, and middle and distance running races). The direct effects on single events involving strength and power, such as lifts, throws, and sprints, are unclear. Further studies are needed to better elucidate the range of protocols (timing and amount of doses) that produce benefits and the range of sports to which these may apply. Individual responses, the politics of sport, and the effects of caffeine on other goals, such as sleep, hydration, and refuelling, also need to be considered.
370 citations
"Caffeine Alters Blood Potassium and..." refers background in this paper
...Athletes in a variety of sports consume caffeine and products containing caffeine to enhance their exercise performance (Burke, 2008; Spriet, 2014)....
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