Relative Energy Deficiency in Sport (RED-S) Risk Indicators and Cardiovascular Responses to HIIT Under Heat Conditions in Female Basketball Players

This study aimed to identify differences in hemodynamic responses, blood pressure, cardiac recovery, and orthostatic responses between female basketball players with risk indicators of Relative Energy Deficiency in Sport (RED-S) and control players following high-intensity interval training (HIIT) under heat conditions. The researcher employed a descriptive comparative approach. The sample consisted of 40 female basketball players during the 2025 sports season, who were classified based on indicators from the IOC REDs CAT2 into a RED-S risk-indicator group (n = 15) and a control group (n = 25). A standardized HIIT protocol was performed under heat conditions, while heart rate, stroke volume, systolic and diastolic blood pressure, cardiac recovery, and orthostatic response indicators were assessed. The results revealed statistically significant differences between the two groups. The RED-S risk-indicator group demonstrated a higher heart rate and lower stroke volume, as well as higher post-exercise systolic and diastolic blood pressure. This group also exhibited a longer cardiac recovery time and greater changes in orthostatic responses compared with the control group. The study concluded that the presence of RED-S risk indicators was associated with less favorable cardiovascular and recovery responses following HIIT under heat conditions in female basketball players.