TY - JOUR
T1 - Effects of aging and exercise training on leg hemodynamics and oxidative metabolism in the transition from rest to steady state exercise
T2 - Role of cGMP signaling
AU - Piil, Peter Kromann
AU - Jørgensen, Tue Smith
AU - Egelund, Jon
AU - Mortensen, Nicolai Rytter
AU - Gliemann, Lasse
AU - Bangsbo, Jens
AU - Hellsten, Ylva
AU - Nyberg, Michael Permin
N1 - CURIS 2018 NEXS 260
PY - 2018/8
Y1 - 2018/8
N2 - 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 restto steady-state exercise engaging the knee-extensor muscles in young (n = 15, 25± 1 yr) and older (n = 15, 72 ± 1 yr) 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 VO2was, however, similar in the two groups as a result of higher (P < 0.05) arteriovenous O2 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.
AB - 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 restto steady-state exercise engaging the knee-extensor muscles in young (n = 15, 25± 1 yr) and older (n = 15, 72 ± 1 yr) 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 VO2was, however, similar in the two groups as a result of higher (P < 0.05) arteriovenous O2 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.
KW - Faculty of Science
KW - Knee-extensor exercise
KW - Sildenafil
KW - PDE5 inhibition
U2 - 10.1152/ajpregu.00446.2017
DO - 10.1152/ajpregu.00446.2017
M3 - Journal article
C2 - 29668326
SN - 0363-6119
VL - 315
SP - R274-R283
JO - American Journal of Physiology: Regulatory, Integrative and Comparative Physiology
JF - American Journal of Physiology: Regulatory, Integrative and Comparative Physiology
IS - 2
ER -