Sex-Related Difference in Muscle Deoxygenation Responses Between Aerobic Capacity-Matched Elderly Men and Women.

Muscle O-2 dynamics during ramp cycling exercise were compared between aerobic capacity-matched elderly men (n = 8, age 65 +/- 2 years) and women (n = 8, age 66 +/- 3 years). Muscle O-2 saturation (SmO2) and relative change in deoxygenated (Delta deoxy-Hb) and total hemoglobin concentration (Delta total-Hb) were monitored continuously during exercise in the vastus lateralis (VL) and gastrocnemius medialis (GM) by near infrared spatial resolved spectroscopy. SmO2 was significantly higher during exercise in women than in men in VL, but not in GM. In VL, Delta deoxy-Hb and Delta total-Hb were significantly higher in men than in women, especially during high intensity exercise. However, no significant difference was observed in Delta deoxy-Hb or Delta total-Hb in GM. Sex-related differences in muscle deoxygenation response may be heterogeneous among leg muscles in elderly subjects.