Skeletal Muscle Deoxygenation and Its Relationship to Aerobic Capacity During Early and Late Stages of Aging

• Published in: Advances in experimental medicine and biology Vol. 1269; p. 77
• Main Authors: Takagi, Shun, Kime, Ryotaro, Murase, Norio, Niwayama, Masatsugu, Sakamoto, Shizuo, Katsumura, Toshihito
• Format: Journal Article
• Language: English
• Published: United States 2021
• Subjects: Adult; Aged; Aging; Exercise Test; Exercise Tolerance; Hemoglobins - metabolism; Humans; Middle Aged; Muscle, Skeletal - metabolism; Oxygen - metabolism; Oxygen Consumption; Young Adult; Muscle O2 extraction; Young adults; Middle-aged adults; Convective O2 transport; Elderly adults
• ISSN: 0065-2598
• DOI: 10.1007/978-3-030-48238-1_12

The aim of this study was to compare muscle O dynamics during exercise among elderly (n = 10, age: 73 ± 3 years), middle-aged (n = 9, age: 50 ± 6 years), and young (n = 10, age: 25 ± 3 years) adults. The subjects performed ramp bicycle exercise until exhaustion. Muscle O saturation (SmO ) and relative changes from rest in oxygenated hemoglobin/myoglobin (∆oxy-Hb/Mb), deoxygenated hemoglobin/myoglobin (∆deoxy-Hb/Mb), and total hemoglobin concentration (∆total-Hb) were monitored continuously at the vastus lateralis muscle by near-infrared spatial resolved spectroscopy. At given absolute workloads, SmO and ∆oxy-Hb/Mb were significantly lower in elderly than the other groups, while ∆deoxy-Hb/Mb, ∆total-Hb, and pulmonary O uptake (VO ) were similar among the three groups. In contrast, there were no significant differences in muscle O dynamics during submaximal exercise between middle-aged and young subjects. Muscle O dynamics may be relatively preserved in early stages of aging, although muscle deoxygenation is enhanced in late stages of aging, probably due to reduced convective O supply. Moreover, change in SmO was significantly positively correlated with peak VO in the elderly, while a significant negative relationship was observed in middle-aged and young subjects. In late stages of aging, diminished peak VO may be caused by attenuated convective O transport, while reduced peak VO can be explained by lowered muscle O extraction in early stages of aging.