Effects of aging and exercise training on leg hemodynamics and oxidative metabolism in the transition from rest to steady state exercise: Role of cGMP signaling

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Peter Kromann Piil, Tue Smith Jørgensen, Jon Egelund, Nicolai Rytter Mortensen, Lasse Gliemann, Jens Bangsbo, Ylva Hellsten, Michael Permin Nyberg

Aging is associated with slower skeletal muscle O2 uptake (VO2) kinetics; however, the mechanisms underlying this effect of age are unclear. Also, the effects of exercise training in elderly on the initial vascular and metabolic response to exercise remain to be elucidated. We measured leg hemodynamics and oxidative metabolism in the transition from rest to steady state exercise engaging the knee-extensor muscles in young (n=15, 25{plus minus}1 years) and older (n=15, 72{plus minus}1 years) subjects before and after a period of aerobic high-intensity exercise training. To enhance cGMP signaling, pharmacological inhibition of phosphodiesterase 5 (PDE5) was performed. Before training, the older group had a slower ( P˂0.05) increase in femoral arterial blood flow and leg vascular conductance in the transition from rest to steady state exercise at low- and moderate-intensity compared with the young group. The rate of increase in leg VO2 was, however, similar in the two groups as a result of higher ( P<0.05) a-vO2 difference in the older group. Potentiation of cGMP signaling did not affect the rate of increase in blood flow or VO2 in either group. Exercise training augmented ( P<0.05) the increase in leg vascular conductance and blood flow during the onset of moderate-intensity exercise in both groups without altering VO2. These findings suggest that an age-related reduction in the initial vascular response to low- and moderate-intensity knee-extensor exercise is not limiting for VO2 in older individuals. A lower blood flow response in aging does not appear to be a result of reduced cGMP signaling.

Original languageEnglish
JournalAmerican Journal of Physiology: Regulatory, Integrative and Comparative Physiology
Volume315
Issue number2
Pages (from-to)R274-R283
Number of pages10
ISSN0363-6119
DOIs
Publication statusPublished - 2018

ID: 195288142