Enhanced oxygen extraction and reduced flow heterogeneity in exercising muscle in endurance-trained men

: Kalliokoski KK, Oikonen V, Takala TO, Sipila H, Knuuti J, Nuutila P

: 2001

: Am.J.Physiol Endocrinol.Metab

: 280

: 6

: E1015

: E1021

DOI: https://doi.org/10.1152/ajpendo.2001.280.6.E1015

: PM:11350784

The aim of this study was to investigate the effects of endurance training on skeletal muscle hemodynamics and oxygen consumption. Seven healthy endurance-trained and seven untrained subjects were studied. Oxygen uptake, blood flow, and blood volume were measured in the quadriceps femoris muscle group by use of positron emission tomography and [15O]O2, [15O]H2O, and [15O]CO during rest and one-legged submaximal intermittent isometric exercise. The oxygen extraction fraction was higher (0.49 +/- 0.14 vs. 0.29 +/- 0.12; P = 0.017) and blood transit time longer (0.6 +/- 0.1 vs. 0.4 +/- 0.1 min; P = 0.04) in the exercising muscle of the trained compared with the untrained subjects. The flow heterogeneity by means of relative dispersion was lower for the exercising muscle in the trained (50 +/- 9%) compared with the untrained subjects (65 +/- 13%, P = 0.025). In conclusion, oxygen extraction is higher, blood transit time longer, and perfusion more homogeneous in endurance-trained subjects compared with untrained subjects at the same workload. These changes may be associated with improved exercise efficiency in the endurance-trained subjects

Adult, blood, Blood Pressure, blood supply, Blood Volume, Heart Rate, Hemodynamics, Humans, Isometric Contraction, Male, Muscle,Skeletal, Oxygen, Oxygen Consumption, Perfusion, Physical Endurance, physical fitness, physiology, radionuclide imaging, Regional Blood Flow, Rest, Tomography,Emission-Computed