title: Sarcopenia Is Associated With Lower Skeletal Muscle Capillarization and Exercise Capacity in Older Adults.
abstract: Skeletal muscle capillary rarefaction limits the transcapillary transport of nutrients and oxygen to muscle and may contribute to sarcopenia and functional impairment in older adults. We tested the hypothesis that skeletal muscle capillarization and exercise capacity (VO2max) are lower in sarcopenic than in nonsarcopenic older adults and that the degree of sarcopenia is related to lower skeletal muscle capillarization.
  
  
  
  Body composition, VO2max, and vastus lateralis capillarization were determined in 76 middle-aged and older men and women (age = 61±1 years, body mass index [BMI] = 30.7±0.5kg/m(2) [mean ± SEM]). Participants were classified as sarcopenic if appendicular lean mass divided by BMI (ALMBMI) was less than 0.789 for men or less than 0.512 for women.
  
  
  
  Sarcopenic subjects (ALMBMI = 0.65±0.04, n = 16) had 20% lower capillary-to-fiber ratio, as well as 13% and 15% lower VO2max expressed as mL/kg/min or L/min, respectively, compared with sex-, race-, and age-matched participants without sarcopenia (ALMBMI = 0.81±0.05, n = 16; p < .05). In all 76 subjects, ALMBMI, thigh muscle cross-sectional area, and VO2max correlated directly with capillarization (r = .30-.37, p ≤ .05), after accounting for age, sex, and race.
  
  
  
  These findings suggest that low skeletal muscle capillarization is one factor that may contribute to sarcopenia and reduced exercise capacity in older adults by limiting diffusion of substrates, oxygen, hormones, and nutrients. Strategies to prevent the aging-related decline in skeletal muscle capillarization may help to prevent or slow the progression of sarcopenia and its associated functional declines in generally healthy older adults.
authors.affiliation: Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore. Baltimore Veterans Affairs Geriatric Research, Education and Clinical Center, and Research and Development Service, Baltimore, Maryland. sprior@grecc.umaryland.edu.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Prior
authors.affiliation: Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore. Baltimore Veterans Affairs Geriatric Research, Education and Clinical Center, and Research and Development Service, Baltimore, Maryland.
authors.forename: Alice S
authors.initials: AS
authors.lastname: Ryan
authors.affiliation: Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore. Baltimore Veterans Affairs Geriatric Research, Education and Clinical Center, and Research and Development Service, Baltimore, Maryland.
authors.forename: Jacob B
authors.initials: JB
authors.lastname: Blumenthal
authors.affiliation: Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore. Baltimore Veterans Affairs Geriatric Research, Education and Clinical Center, and Research and Development Service, Baltimore, Maryland.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Watson
authors.affiliation: Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore. Baltimore Veterans Affairs Geriatric Research, Education and Clinical Center, and Research and Development Service, Baltimore, Maryland.
authors.forename: Leslie I
authors.initials: LI
authors.lastname: Katzel
authors.affiliation: Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore. Baltimore Veterans Affairs Geriatric Research, Education and Clinical Center, and Research and Development Service, Baltimore, Maryland.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Goldberg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001823:Body Composition; D015992:Body Mass Index; D002196:Capillaries / Q000473:pathology; D003430:Cross-Sectional Studies; D015444:Exercise; D005080:Exercise Test; D005260:Female; D015577:Geriatric Assessment / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000098:blood supply*; D055948:Sarcopenia / Q000175:diagnosis* / Q000503:physiopathology / Q000517:prevention & control
keywords: Exercise; Muscle; Sarcopenia; Vascular