Purpose: We aimed to clarify the compensatory changes in oxygenation in non-active versus active muscles during incremental exercise. Methods: Fifteen male volunteers (age, 21.1 ± 0.5 years) underwent cardiopulmonary exercise testing (CPET) using a cycle ergometer ramp protocol, while maintaining the left upper extremity in a drooping position. We continuously recorded oxygenated hemoglobin (O2Hb), deoxygenated hemoglobin (HHb), total hemoglobin (THb), and tissue oxygen saturation (StO2) in the left vastus lateralis (active muscle) and triceps brachii (non-active muscle), as well as cardiopulmonary parameters, during the test. Results: There were significant interactions between time and muscles for all changes in O2Hb (p < 0.001), HHb (p < 0.001), THb (p < 0.001), and StO2 (p < 0.001). In the non-active muscle, O2Hb and StO2 remained higher than at rest until the 40% point of the test, unlike in the active muscle. HHb increased from the 80% point in the non-active muscle, but it increased immediately after the start of the test in the active muscle. THb showed no significant change in the non-active muscle, but it continued to increase immediately after the start of the test in the active muscle. Conclusion: During CPET, O2Hb and StO2 in the non-active muscle remained higher in the low- to moderate-intensity phases than in the rest phase and decreased in the high-intensity phase, unlike in the active muscle.