ECSS Paris 2023: OP-PN10
INTRODUCTION: The administration of caffeine from chewing gum is more rapidly absorbed into the blood stream, resulting in a faster onset of effects versus alternative forms of ingestion. Caffeine gum presents a feasible solution during sporting scenarios where time is limited and the ability to maintain performance and cognition is crucial, such as soccer matches that enter the extra-time period. Extra-time is an additional 30-min period of match-play required when matches are tied, and an outright winner is required, for example during the knockout phase of major tournaments and domestic cup competitions, such as the FIFA World Cup. The aim of the study was to assess the effects of caffeine gum on the perceptual-cognitive and physical performance responses during and following extra-time in soccer players. METHODS: Following institutional ethical approval, twelve male semi-professional soccer players (age: 22 ± 3 years, stature: 1.78 ± 0.06 m, mass: 75 ± 9 kg) with 14 ± 4 years of soccer experience performed 120-min soccer-specific exercise on two separate occasions. In a triple-blind, randomised, crossover design, players chewed a caffeinated (200-mg; caffeine) or control (0-mg; placebo) gum for 5-min following 90-min of soccer-specific exercise. Perceptual-cognitive skills (i.e., passing accuracy, reaction time, composure, adaptability) were assessed using a soccer-specific virtual reality simulator, collected pre- and post-trial. Measures of 15- and 30-m sprint time, reactive-strength index and vertical jump height were obtained at pre-trial, half-time, 90-min and post-trial. RESULTS: A linear mixed model found that caffeine gum attenuated declines in reaction time (pre: 90.77 ± 0.77 AU to post: 90.65 ± 0.77 AU) by a further 4.15% than placebo (pre: 92.13 ± 0.77 AU to post: 88.19 ± 0.77 AU; p <0.01). Caffeine gum reduced composure by 4.68% (pre: 69.11 ± 0.84 AU to post: 65.87 ± 0.84 AU) versus placebo (pre: 68.84 ± 0.84 AU to post: 68.34 ± 0.84 AU; p <0.01). Time effects were found for reaction time in the placebo condition, and for composure in the caffeine group (p <0.01). Caffeine gum did not influence any other variables (p >0.05). CONCLUSION: Where caffeine gum is consumed by players prior to extra-time, reaction time increases but composure may be compromised, and sprint and jump performance remain unchanged. Caffeine gum might provide a practical ergogenic solution to cognitive declines during soccer match-play, given the limited time for nutritional interventions in the short 5-min break at 90-min. Improvements in reaction speed are likely to provide advantages concerning anticipation and responding quickly to rapidly evolving scenarios on the pitch. However, maintaining composure and self-control is crucial for highly pressured situations and techniques requiring fine motor skills or refined judgment. Further work could evaluate the co-ingestion of caffeine and substances like L-theanine that modulate the anxiety inducing effects of caffeine.
Read CV Adam FieldECSS Paris 2023: OP-PN10
INTRODUCTION: Prolonged exercise in the heat has physiological and metabolic consequences, instigating inexorable rises in core temperature [1], causing exercise to cease early. Isolated caffeine supplementation is often reported to enhance endurance performance, yet has a deleterious effect on thermoregulation and performance in the heat [2]. Conversely, taurine enhances thermoregulatory defences and lowers core temperature, whilst improving endurance performance [3]. Caffeine and taurine are commonly co-ingested before exercise due to their prevalence in sport drinks, but their combined effects on thermoregulation are not known. Therefore, we evaluated the effects of oral caffeine and taurine co-ingestion on time to exhaustion (TTE) and thermoregulatory responses to cycling in the heat at the gas exchange threshold (GET). METHODS: Ten healthy, non-heat acclimated participants took part in this double-blind crossover study. Participants completed a TTE in the heat (35°C; 40% RH), cycling at a power output associated with the GET, 1 h after ingesting: Caffeine (5mg/kg) and Taurine (50mg/kg) or placebo. Exercising thermo-physiological measures included: breath-by-breath pulmonary gas exchange, core and mean skin temperatures, whole-body sweat rate and heart rate. Heat production and mean skin blood flow were determined using partitional calorimetry. Two-way analyses of variance were used to determine the effect of condition (supplement vs. placebo) and time (10% to 100% epochs) on all thermo-physiological responses. Data are reported as mean±SD. RESULTS: There were no differences in TTE between conditions (p=0.608; placebo = 39.23 ± 14.27 min and supplement = 40.92 ± 17.66 min). Rate of oxygen consumption (p=0.017), minute ventilation (p=0.029) and heat production (p=0.019) were significantly higher following the supplement. There were no differences between conditions for skin (p=0.539) and core temperature (p=0.699), mean skin blood flow (p=0.119), heart rate (p=0.864), respiratory exchange ratio (p=0.546) and whole-body sweat rate (p=0.897). CONCLUSION: There was no ergogenic effect following pre-exercise co-ingestion of caffeine and taurine in the heat. However, the combined supplement increased oxygen consumption, pulmonary minute ventilation and heat production. Despite these effects, which indicate a thermogenic effect of the supplement, there were no changes in core or skin temperature or sweating between conditions, thus indicating minimal effects on thermoregulation. The combined supplementation might offset the apparent thermogenicity, denoted by the increase in heat production, which can be driven by caffeine supplementation [2]. Therefore, current results are unclear and further work is required to understand how thermal gain was supressed whilst experiencing greater heat production after ingesting mixed ergogenic doses of caffeine and taurine. References [1] González-Alonso et al., (1999). J of Phys [2] Peel et al., (2021). Sports med [3] Page et al., (2019). EJ of Sport sci
Read CV James AggettECSS Paris 2023: OP-PN10
INTRODUCTION: Breathing discomfort increases during exhaustive endurance exercise and limits the exercise capacity (1). The time to exhaustion (TTE) of endurance running was prolonged by L-menthol administration through mitigation of breathing discomfort (2). This study aims to examine whether the TTE prolongation by L-menthol is due to the improvement in cardiorespiratory function or by modification of brain activity-related discomfort perception (3). METHODS: Fourteen males (age 39.5±8.8 years, Wpeak 264.7±34.1 w) performed two cycling TTE trials at 85% Wpeak intensity after 20 minutes of warm-up session (WUS) at 60% Wpeak. The participants were randomly assigned to TTE in a crossover design of either water (WA) or L-menthol solution (LM; 0.01% concentration) ingestion with a 7-day interval. The experimental solution (25ml, 30C) was taken three times every 5 minutes during the WUS and once before TTE. Breathing comfort (BC), RPE, and SpO2 were measured 1 minute after each ingestion in the WUS in addition to pre and post warm-up and pre and post TTE. VO2, VCO2, VE, and respiratory rate (RR) were measured during TTE. 64-channel EEG and HR were recorded throughout the sessions. The power spectrum of alpha (8-12Hz) and beta (12-30Hz) bands were measured using Fast Fourier Transform from preprocessed EEG data. The TTE time was analyzed by the Friedman test. All other measurements were compared by a two-way repeated measures ANOVA (condition*time) with Geisser-Greenhouse correction. RESULTS: TTE in LM was longer than WA (WA: 343.5±192.7, LM: 447.3±311.1, P<0.05). No difference was observed in VO2, VCO2, VE, RR and HR during TTE, nor BC, RPE, and SpO2 for pre- and post-TTE. The beta power spectrum in the left centro-parietal area was significantly decreased in LM as compared to WA (condition P<0.05, time P<0.01) during TTE, however neither the alpha nor beta power during WUS was significantly different. HR, RPE, and SpO2 were the same throughout the WUS. WA decreased BC as exercise progressed during WUS (time P<0.05), whereas LM kept the same level. CONCLUSION: L-menthol administration improved endurance time of exhaustive cycling. An attenuation of left centro-parietal cortical activity was observed under L-menthol condition. Activation of centro-parietal region due to high respiratory flow may have been attenuated by L-menthol. Such attenuation was not observed during warm-up, a moderate-intensity exercise, although L-menthol mitigated discomfort of breathing. REFERENCES: 1. Kearon et al., Eur Respir J, 1991 2. Tsutsumi et al., Eur J Sports Sci, 2022 3. Von Leupoldt et al., Psychophysiol, 2011
Read CV Yoshiko TsutsumiECSS Paris 2023: OP-PN10