title: Aging affects spatial distribution of leg muscle oxygen saturation during ramp cycling exercise.
abstract: We compared muscle oxygen saturation (SmO2) responses in several leg muscles and within a single muscle during ramp cycling exercise between elderly men (n = 8; age, 65 ± 3 years; ELD) and young men (n = 10; age, 23 ± 3 years; YNG). SmO2 was monitored at the distal site of the vastus lateralis (VLd), proximal site of the vastus lateralis (VLp), rectus femoris (RF), vastus medialis (VM), biceps femoris (BF), gastrocnemius lateralis (GL), gastrocnemius medialis (GM), and tibialis anterior (TA) by near-infrared spatial resolved spectroscopy. During submaximal exercise, significantly lower SmO2 at a given absolute work rate was observed in VLd, RF, BF, GL, and TA but not in VLp, VM, and GM in ELD than in YNG. In contrast, at all measurement sites, SmO2 at peak exercise was not significantly different between groups. These results indicate that the effects of aging on SmO2 responses are heterogeneous between leg muscles and also within a single muscle. The lower SmO2 in older men may have been caused by reduced muscle blood flow or altered blood flow distribution.
authors.affiliation: Department of Sports Medicine for Health Promotion, Faculty of Medicine, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, 160-8402, Japan. stakagi@tokyo-med.ac.jp.
authors.forename: Shun
authors.initials: S
authors.lastname: Takagi
authors.affiliation: Department of Sports Medicine for Health Promotion, Faculty of Medicine, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, 160-8402, Japan.
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Kime
authors.affiliation: Department of Sports Medicine for Health Promotion, Faculty of Medicine, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, 160-8402, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Murase
authors.affiliation: Department of Sports Medicine for Health Promotion, Faculty of Medicine, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, 160-8402, Japan.
authors.forename: Tsubasa
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Department of Sports Medicine for Health Promotion, Faculty of Medicine, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, 160-8402, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Osada
authors.affiliation: Department of Electrical and Electronic Engineering, Faculty of Engineering, Shizuoka University, Shizuoka, 432-8561, Japan.
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Niwayama
authors.affiliation: Department of Sports Medicine for Health Promotion, Faculty of Medicine, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, 160-8402, Japan.
authors.forename: Toshihito
authors.initials: T
authors.lastname: Katsumura
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001107:Architectural Accessibility; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000098:blood supply*; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism; D010100:Oxygen / Q000097:blood / Q000378:metabolism*; D012039:Regional Blood Flow / Q000502:physiology; D019265:Spectroscopy, Near-Infrared / Q000379:methods; D055815:Young Adult
chemical_list: D010100:Oxygen