Browsing by Author "Brito de Souza, Diego"
Now showing 1 - 4 of 4
- Results Per Page
- Sort Options
Item Acute caffeine intake increases muscle oxygen saturation during a maximal incremental exercise test.(British Journal of Clinical Pharmacology, 2019) Ruiz Moreno, Carlos; Lara, Beatriz; Brito de Souza, Diego; Gutiérrez Hellín, Jorge; Romero-Moraleda, Blanca; Cuéllar Rayo, Ángel; Del Coso, JuanAims: The main mechanism behind caffeine’s ergogenicity lies in its tendency to bind to adenosine A1 and A2A receptors. However, other mechanisms might contribute to caffeine’s ergogenicity. The aim of this investigation was to analyze the effects of caffeine on muscle oxygen saturation during exercise of increasing intensity. Methods: Thirteen healthy and active individuals volunteered to participate in a randomized, double blind, placebo-controlled crossover trial. During two different trials, participants either ingested a placebo (cellulose) or 3 mg/kg of caffeine. After waiting for 60 min to absorb the substances, participants underwent a maximal ramp cycle ergometer test (25 W/min). Near infrared spectrometers were positioned on each leg’s vastus lateralis to monitor tissue O2 saturation. Blood lactate concentration was measured 1 min after the end of the exercise test. Results: In comparison to the placebo, the ingestion of caffeine improved the maximal wattage (258±50 vs 271±54 W, respectively, P < 0.001) and blood lactate concentration (11.9±3.8 vs 13.7±3.5 mmol/L, P = 0.029) at the end of the test. Caffeine increased muscle oxygen saturation at several exercise workloads with a main effect found in respect to the placebo (F = 6.28, P = 0.029). Peak pulmonary ventilation (124±29 vs 129±23 L/min, P=0.035) and VO2peak (3.18±0.70 vs 3.33±0.88 L/min, P=0.032) were also increased with caffeine. Conclusion: Acute ingestion of 3 mg/kg of caffeine improved peak aerobic performance while caffeine-induced changes seen in muscle oxygen saturation, pulmonary ventilation, and blood lactate accumulation suggest that these mechanisms might also contribute to caffeine’s ergogenic effect.Item Effect of ambient temperature on fat oxidation during an incremental cycling exercise test.(European Journal of Sport Science, 2021) Ruiz Moreno, Carlos; Gutiérrez Hellín, Jorge; González García, Jaime; Giráldez Costas, Verónica; Brito de Souza, Diego; Del Coso, JuanAim: The objective of this current research was to compare fat oxidation rates during an incremental cycling exercise test in a temperate vs. hot environment. Methods: Twelve healthy young participants were recruited for a randomised crossover experimental design. Each participant performed a VO2max test in a thermoneutral environment followed by two cycling ramp test trials, one in a temperate environment (18.3°C) and another in a hot environment (36.3°C). The ramp test consisted of 3-min stages of increasing intensity (+10% of VO2max) while gas exchange, heart rate and perceived exertion were measured. Results: During exercise, there was a main effect of the environment temperature on fat oxidation rate (F = 9.35, P = 0.014). The rate of fat oxidation was lower in the heat at 30% VO2max (0.42 ± 0.15 vs.0.37 ± 0.13 g/min; P = 0.042), 60% VO2max (0.37 ± 0.27 vs.0.23 ± 0.23 g/min; P = 0.018) and 70% VO2max (0.22 ± 0.26 vs.0.12 ± 0.26 g/min; P = 0.007). In addition, there was a tendency for a lower maximal fat oxidation rate in the heat (0.55 ± 0.2 vs.0.48 ± 0.2 g/min; P = 0.052) and it occurred at a lower exercise intensity (44 ± 14 vs.38% ± 8% VO2max; P = 0.004). The total amount of fat oxidised was lower in the heat (5.8 ± 2.6 vs 4.6 ± 2.8 g; P = 0.002). The ambient temperature also produced main effects on heart rate (F = 15.18, P = 0.005) and tympanic temperature (F = 25.23, P = 0.001) with no effect on energy expenditure (F = 0.01, P = 0.945). Conclusion: A hot environment notably reduced fat oxidation rates during a ramp exercise test. Exercising in the heat should not be recommended for those individuals seeking to increase fat oxidation during exercise.Item Gender Differences in Prevalence and Patterns of Dietary Supplement Use in Elite Athletes.(Research Quarterly for Exercise and Sport, 2020) Aguilar Navarro, Millán; Baltazar Martins, Gabriel; Brito de Souza, Diego; Muñoz Guerra, Jesús; Plata, María del Mar; Del Coso, JuanPurpose: Dietary supplement use by athletes has been the topic of previous research; however, the lack of homogeneity among published studies makes it difficult to analyze the differences, if any, in the patterns of use between male and female athletes. The aim of this study was to determine gender differences in the patterns of dietary supplement use by elite athletes. Methods: A total of 504 elite athletes (329 males and 175 females) participating in individual and team sports completed a validated questionnaire on dietary supplement use during the preceding season. The dietary supplements were categorized according to the latest IOC consensus statement. Results: A higher proportion of male versus female athletes (65.3 versus 56.5%, p < .05) consumed dietary supplements. Both male and female athletes reported a similar mean consumption of dietary supplements (3.2 ± 2.1 versus 3.4 ± 2.3 supplements/season, respectively; p = .45). Protein supplements were the most commonly consumed supplements in male athletes (49.8%) and their prevalence was higher than in female athletes (29.3%, p < .01). In females, multivitamins (39.4%) and branched-chain amino acids (39.4%) were the most commonly consumed supplements and iron supplementation was more prevalent than in males (22.2% versus 10.2%, p = .01). A higher proportion of male athletes relied on themselves to plan dietary supplements use (48.0%), while female appeared to rely more on doctors (34.0%, p < .01). Conclusion: In summary, male athletes had a slightly higher prevalence in the use of supplements than their female counterparts, specifically regarding protein supplements, and were more involved in the self-prescription of supplements.Item Prevalence and patterns of dietary supplement use in elite Spanish athletes.(Journal of the International Society of Sports Nutrition, 2019) Baltazar-Martins, Gabriel; Brito de Souza, Diego; Aguilar Navarro, Millán; Muñoz-Guerra, Jesús; Plata, María del Mar; Del Coso, JuanBackground: Dietary supplementation is a common strategy to achieve a specific health status or performance benefit. Several investigations have focused on the prevalence of dietary supplement use by athletes. However, information on how athletes manage the use and purchase of dietary supplements is scarce. Methods: Five hundred and twenty-seven high-performance athletes (346 males and 181 females), participating in individual and team sports, completed a validated questionnaire about use and purchase patterns of dietary supplements. The dietary supplements were categorized according to the International Olympic Committee (IOC) consensus. Results: Sixty four percent of the athletes (n = 337) used dietary supplements (median = 3; range 1 to 12). Age, sex, type of sport, level of competition, and professionalism influenced the prevalence of dietary supplement use (all p < 0.05). The most prevalent dietary supplement consumed was proteins (41%; n = 137), followed by amino acids/BCAA-based supplements (37%; n = 124). Additionally, as per group of supplements according to IOC consensus, 18% of the supplements were rated as having a low level of scientific evidence (e.g., glutamine, HMB, L-carnitine, etc). Most athletes (45%, n = 152) purchased dietary supplements in a store and 24% (n = 81) obtained them from a sponsor. Most athletes also (42%, n = 141) reported a self-organization of supplementation and did not consult with any professional. Last, 81% (n = 273) of athletes consuming supplements did not know any platform to check supplement safety/quality. For those who do not use dietary supplements (36% of the total sample, n = 190), most reported that they do not consider supplements necessary (72%, n = 137). Conclusion: Dietary supplementation appears to be widely used in sport with a considerable proportion of athletes consuming supplements with low level of scientific evidence. Additionally, athletes seem to rely on inadequate sources of information and may be largely unaware of sources to detect supplement contamination.