Blood and muscle responses to sodium bicarbonate supplementation and subsequent exercise performance

Author(s)

Pedro Henrique Lopes Perim

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2021-12-01

Examining board members

Bryan Saunders; Eimear Bernadette Dolan; Vitor de Salles Painelli; Alessandro Moura Zagatto

• Advisor: Bryan Saunders

Abstract

The sodium bicarbonate supplementation has strong scientific evidence that show its ergogenic effect in improving exercise capacity and performance. This is explained by the fact that oral ingestion of sodium bicarbonate causes an increase in blood bicarbonate concentrations and exerts an extracellular buffering effect during physical exercise, due to increased efflux of hydrogen ions (H+ ) from the muscle to the blood, where it can be buffered by bicarbonate and consequently reducing muscle acidosis. The aim of this study was to evaluate the changes in the activity of transporters related to this efflux of H+ (MCT1 and MCT4) generated by acute sodium bicarbonate supplementation and the subsequent effect on sports performance. For this, 12 healthy men (age 24 years ± 2; height 1.78m ± 0.05 and body weight 84.9 kg ± 13.5) participated, who went to the laboratory in two familiarizations and two separate main visits for a double blinded, placebo-controlled, randomized study. Participants were supplemented with an acute dose of 0.3 g/kg of sodium bicarbonate or placebo (Farmácia Analítica, Brazil) in opaque gelatin capsules. One hour before supplementation, a blood sample was collected for subsequent analysis in blood gases and the first muscle biopsy was performed. The second muscle biopsy was performed 90 minutes after supplementation and before warming up for the physical test together with new blood collections. Finally, immediately after the test, a third muscle biopsy and new blood collections were performed. In the moments before supplementation and 90 minutes after, a questionnaire was applied to assess the side effects associated with sodium bicarbonate supplementation. The results of this study show that sodium bicarbonate supplementation was not able to improve sports performance in the 1-km time trial compared to the placebo group, including reducing sports performance (P = 0.90). Sodium bicarbonate supplementation promoted a preexercise alkalosis (P = 0.0001), but this was not associated with improved sports 16 performance. Subsequent analyzes showed no difference in mean heart rate (P=0.44), maximum heart rate (P=0.11), subjective perceived exertion (P=0.133), gene expression of MCT1 (P=0.7009) and MCT4 (P=0.9939) and muscle buffering capacity (P=0.9943) between the sodium bicarbonate and placebo groups. In conclusion, sodium bicarbonate supplementation promoted a pre-exercise alkalosis, but this was not associated with improvements in sports performance and physiological and molecular changes that justify its ergogenic effect (AU)

• FAPESP's process: 18/01594-5 - Blood and muscle responses to sodium bicarbonate supplementation and subsequent exercise performance
• Grantee: Pedro Henrique Lopes Perim
• Support Opportunities: Scholarships in Brazil - Master