Efeitos da suplementação de nitrato e da hipóxia intermitente normobárica sobre o exercício intervalado de alta intensidade: um ensaio clínico duplo-cego, randomizado e controlado

• Grant number: 25/12849-8
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: May 18, 2026
• End date: May 17, 2027
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Marcelo Papoti
• Grantee: Matheus Simionato Firmino
• Supervisor: Olivier Girard
• Host Institution: Escola de Educação Física e Esporte de Ribeirão Preto (EEFERP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Institution abroad: University of Western Australia (UWA), Australia
• Associated to the scholarship: 24/04856-1 - Effects of inter-effort recovery hypoxia training on hematological profile, energy metabolism and physical fitness in individuals with type 2 diabetes mellitus, BP.DD

Abstract

Inter-effort recovery hypoxia (IEH) induces systemic hypoxia during rest intervals without impairing training quality. Dietary nitrate (NO3-) supplementation may enhance performance by improving nitric oxide availability and oxygen utilization, particularly in hypoxic conditions. However, the potential synergistic effects of combining IEH with NO3- during exhaustive high-intensity interval exercise (HIIE) remain uninvestigated. This double-blind, randomized, controled trial will evaluate the effects of NO3- and IEH on performance and physiological responses during HIIE to exhaustion. Thirty physically active participants will be randomized to either an IEH group (FiO2 = 0.15; n = 15) or a normoxia group (FiO2 = 0.21; n = 15). Both groups will undergo two crossover conditions in a counterbalanced design: four days of beetroot juice supplementation (12.4 mmol NO3-) or placebo, interpersed by a seven-day washout period. Supplementation will be followed by a HIIE session consisting of 90s bouts at 110% of maximal oxygen uptake intensity with 60s of passive recovery, performed until exhaustion. In the IEH condition, hypoxic air will be inhaled only during the recovery intervals. Outcomes include performance, gas exchange, muscle oxygenation, blood biomarkers, and others physiological and perceptual training load. Generalized linear mixed models will be used for statistical analysis. Understanding these combined mechanisms could lead to new approaches for improving oxygen utilization and training quality, with implications for both athletic performance and clinical populations.