Evaluating Local Muscle Oxygen Saturation: Ischemic Preconditioning Protocols and the Myth of Overcompensation
(Moacir Marocolo, Rhaí A. Arriel, Guilherme Guedes, Anderson Meireles, Michal Krzysztofik, Jakub Chycki, Adam Zajac, Hiago L. R. Souza)

Ischemic preconditioning (IPC) is a promising strategy to enhance athletic performance and recovery by improving local muscle oxygen saturation. This study aimed to investigate the effects of different IPC protocols on muscle oxygenation in physically active healthy men. Thirty-four subjects were randomized into three groups and underwent four occlusion cycles of duration of three (IPC-3), five (IPC-5) or seven (IPC-7) min in only one limb. Near-infrared spectroscopy was used to assess oxygenated and deoxygenated hemoglobin levels, calculating total hemoglobin and oxygen saturation percentage (TSI%). Results showed significant improvements in muscle oxygenation following IPC, with variations in minimum, peak, and mean values across protocols. IPC-5 demonstrated the most consistent enhancements in oxygen saturation levels, with statistically significant differences observed in TSI% values during occlusion and reperfusion phases compared to IPC-3 (p < 0.05) and IPC-7 (p < 0.05), without supercompensation of TSI% during reperfusion phases compared to baseline. Specifically, IPC-5 induced the greatest increase in oxygenation in the contralateral limb compared to IPC-3 and IPC-7. These findings suggest that IPC, particularly the five-min protocol, effectively enhances local muscle oxygenation in non-occluded limbs, which may contribute to improved athletic performance and recovery, mainly under conditions where the exercise or testing does not directly involve cuffed limbs.