Age-related decreases in basal limb blood flow in humans: time course, determinants and habitual exercise effects.
Basal whole-limb blood flow is lower in older than in young healthy sedentary men due to a lower limb vascular conductance. In Study 1, we determined whether age-associated reductions in basal whole-leg (femoral artery) blood flow and vascular conductance are modulated by habitual physical activity by studying 89 healthy men aged 20-35 or 55-75 years (26 sedentary, 31 physically active and 32 endurance exercise trained). Femoral blood flow (duplex Doppler) and vascular conductance were approximately 20-30 % lower (P < 0.01) in the older men in all three physical activity groups. In Study 2, to determine the temporal pattern and relation to local metabolism and lean tissue mass of the age-associated reductions in femoral blood flow, we studied 142 healthy men aged 18-79 years. Femoral blood flow (r = -0.40) and vascular conductance (r = -0.51) were linearly and inversely related to age (both P < 0.001). Leg fat-free mass (r = -0.48) and estimated leg oxygen consumption (r = -0.49) declined with advancing age (both P < 0.001), and were strongly and positively related (r = 0.75; P < 0.001). The age-associated decline in femoral blood flow correlated with the corresponding reductions in leg fat-free mass and estimated leg oxygen consumption (both r = 0.47; P < 0.001). We concluded that: (1) basal whole-limb blood flow and vascular conductance decrease progressively with advancing age in healthy men; (2) reductions in both limb fat-free mass and oxygen consumption are related to the decline in whole-limb blood flow with age; and (3) habitual aerobic exercise does not appear to modulate the age-related reductions in basal limb blood flow and vascular conductance.
Dinenno
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FA
Human Cardiovascular Research Laboratory, Department of Kinesiology and Applied Physiology, University of Colorado at Boulder, Boulder, CO 80309, USA.
Seals
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DR
DeSouza
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CA
Tanaka
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D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001823:Body Composition; D015444:Exercise / Q000502:physiology; D005269:Femur / Q000098:blood supply; D006184:Habits; D006801:Humans; D007866:Leg / Q000033:anatomy & histology / Q000098:blood supply* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D010807:Physical Endurance; D010809:Physical Fitness; D012039:Regional Blood Flow / Q000502:physiology; D013997:Time Factors