Are sex-related differences in fatigability in hot environment impacted by exercise intensity?

• Grant number: 24/07195-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: February 01, 2025
• End date: January 31, 2028
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Alessandro Moura Zagatto
• Grantee: Yago Medeiros Dutra
• Host Institution: Faculdade de Ciências (FC). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

The knowledge about the sex-related differences in fatigability during exercise in hot environment is sparse and improve it can be of great practical use, given the increase in the global average temperature and the greater engagement of females in regular physical exercise (e.g., training, competitions, military combat). Therefore, the present research project aims to investigate whether the sex-related differences in fatigability, already observed in a "neutral" environment (20-22°C, 30-40% RH), also occur in a hot environment and whether these possible discrepancies in hot environment are influenced by the intensity of the effort. Due to anatomical and physiological characteristics, it is possible that the impact of a hot environment on the fatigability of females and males can be influenced by the intensity of the effort being performed. Ten females and 10 males will undergo efforts on a cycle ergometer at an intensity 10% below the respiratory compensation point (RCP, 30 minutes) and 10% above the RCP (15 minutes). Participants will perform efforts in "neutral" (20-22°C, 30-40% RH) and "hot" (40-42°C, 50-60% RH) conditions. Before and immediately after the efforts, maximal voluntary isometric contractions of the knee extensors associated to the twitch interpolation technique will be performed. During efforts, tympanic temperature, cardiorespiratory responses, oxygenation of the vastus lateralis, perceptual responses and electromyography activity of the vastus lateralis and accessory respiratory muscles will be monitored.