Maximal perfusion of skeletal muscle in man.

Abstract

SUMMARY1. Five subjects exercised with the knee extensor of one limb at work loads ranging from 10 to 60 W. Measurements of pulmonary oxygen uptake, heart rate, leg blood flow, blood pressure and femoral arterial-venous differences for oxygen and lactate were made between 5 and 10 min of the exercise.2. Flow in the femoral vein was measured using constant infusion of saline near 0 'C. Since a cuff was inflated just below the knee during the measurements and because the hamstrings were inactive, the measured flow represented primarily the perfusion of the knee extensors.3. Blood flow increased linearly with work load right up to an average value of 57 1 min-. Mean arterial pressure was unchanged up to a work load of 30 W, but increased thereafter from 100 to 130 mmHg. The femoral arterial-venous oxygen difference at maximum work averaged 14-6 % (v/v), resulting in an oxygen uptake of 0-80 1 min-. With a mean estimated weight of the knee extensors of 2-30 kg the perfusion of maximally exercising skeletal muscle of man is thus in the order of 2-5 1 kg-' min', and the oxygen uptake 0-35 1 kg-' min-. 4. Limitations in the methods used previously to determine flow and/or the characteristics ofthe exercise model used may explain why earlier studies in man have failed to demonstrate the high perfusion of muscle reported here.5. It is concluded that muscle blood flow is closely related to the oxygen demand of the exercising muscles. The hyperaemia at low work intensities is due to vasodilatation, and an elevated mean arterial blood pressure only contributes to the linear increase in flow at high work rates. The magnitude of perfusion observed during intense exercise indicates that the vascular bed of skeletal muscle is not a limiting factor for oxygen transport.

Blood temperature and perfusion to exercising and non‐exercising human limbs

“…An important observation was the relationships amongst T B , perfusion and aerobic metabolism during dynamic exercise with the lower and upper limbs alone, or combined lower and upper limb exercise. In agreement with the literature, the rate of rise in blood flow in either exercising limb in relationship to the elevation in limb ${\dot{V}}_{{\mathrm{normalO}}_2}$ was 5.7–6.4 l min −1 l −1 during separate incremental leg and arm exercise (Andersen & Saltin, 1985; Knight et al . 1992; Volianitis & Secher, 2002; Mortensen et al .…”

“…A thermistor (model 94‐030‐2.5F T.D. Probe; Edwards Edslab, Baxter, Irvine, CA, USA) was inserted through the latter catheter for measuring blood flow of the leg (LBF) with the constant‐infusion thermodilution technique (Andersen & Saltin, 1985). To obtain blood samples and measure arm blood flow, a Swan‐Ganz catheter (model 132F5; Edwards Edslab) was inserted into an antecubital vein and advanced to the subclavian vein, with the tip positioned in the midclavicular line (the final position was verified by X‐ray).…”

“…In both studies, limb blood flow was measured with constant‐infusion thermodilution (Andersen & Saltin, 1985). Briefly, ice‐cold saline was infused simultaneously through both the femoral and subclavian veins in study 1 and through the femoral vein in study 2 at flow rates sufficient to decrease blood temperature at the thermistor by 0.5–1.0°C.…”

“…At rest, saline infusions were continued for at least 60 s, while during exercise infusions lasted 15–20 s, until blood temperature had stabilized. Blood flow was calculated using a thermobalance equation (Andersen & Saltin, 1985; González‐Alonso et al . 2000).…”

Effects of the nitric oxide donor, sodium nitroprusside, on resting leg glucose uptake in patients with type 2 diabetes

“…Right femoral venous blood flow was measured by constant-rate infusion of cold saline according to the thermodilution principle before and after each drug infusion [20,21,23]. Cold saline was drawn from a reservoir, and then immediately infused through the femoral venous catheter (5-8°C) using an Angiomat 3000 Injector (LeibelFlarsheim, Sybron Corporation, Cincinnati, OH, USA).…”