Efeitos da suplementação aguda de bicarbonato de sódio em atletas de CrossFit®

Abstract

CrossFit® is a high-intensity sport modality that consists of elements of cardiovascular conditioning, weight lifting, and gymnastic movements. Sodium bicarbonate can lead to performance improvements during high-intensity exercises. However, few studies have investigated the effects of sodium bicarbonate supplementation on specific CrossFit® routines. For this reason, this study aims to examine the effects of acute sodium bicarbonate supplementation in CrossFit® exercises. The present study was defined as an experimental, randomized, double-blind, placebo-controlled, crossover research consisting of CrossFit® practitioners. Seventeen practitioners of the sport participated in the study (age 29 ± 5.2 years; body mass 82.4 ± 9.3 kg; height 1.76 ± 0.05 meters; body mass index 26.54 ± 2.62 kg/m2) with at least one year of regular training. Participants were invited to attend four separate sessions: familiarization with the exercise protocol, a control session, and two randomized intervention sessions (placebo and sodium bicarbonate). Participants ingested 0.3 g/kg of body weight of sodium bicarbonate or placebo (starch) 120 minutes before exercising. CrossFit® performance was evaluated using the Fran benchmark followed by a 500-meter row on a rowing machine. Neuromuscular fatigue was assessed pre and post-exercise using a countermovement vertical jump. Fingertip blood samples were collected at various times during the protocol for analysis of pH, bicarbonate, lactate, base excess, SBC, glucose. Heart rate was recorded throughout the protocol and the assessment of perceived exertion (RPE) was recorded immediately after the end of the two exercises. A questionnaire was used to assess symptoms of gastrointestinal discomfort during the two hours before the beginning of the protocol. Fran, Remo, Session RPE, blood values (pH, bicarbonate, lactate, base excess, SBC, glucose), jumping performance (height, power), and heart rate were analyzed using a mixed model. The participants were considered a random factor for all mixed models. The effect size was also calculated. In all analyses, the significance level was p < 0.05. A statistically significant effect was found for the Fran benchmark (P = 0.003) with a 7.23% percent delta between sodium bicarbonate and the placebo. There was no significant difference between the preparations in the 500-meter row. There was no difference in height and power in the countermovement vertical jump, heart rate, and RPE between sessions. After the sodium bicarbonate supplementation, there was an increase of serum bicarbonate of 39.63% and serum pH (P = <0.0001). Volunteers did not present severe gastric discomfort that could compromise the progress of the protocol. In conclusion, our study showed that sodium bicarbonate improved CrossFit® performance compared to the control session, but not to the placebo. It did not reduce the neuromuscular fatigue of the volunteers, the volunteers' responses such as heart rate and PSE show that the Fran benchmark is an exercise predominantly of high intensity.