Cardiac Output, Leg Blood Flow and Oxygen Uptake During Foot Plantar Flexions

When studying the adjustment of muscle perfusion during exercise, the influence of central factors (e.g. blood volume, central blood pressure and venous return) can be reduced by choosing small muscle groups. In the present study parallel determinations of cardiac output (CO), leg blood flow (LBF) and pulmonary oxygen (V˙O₂) uptake were performed in 9 healthy male subjects at the onset and cessation of dynamic foot plantar flexions. The volunteers exercised with both feet for 5 minutes at 3 different resistances corresponding to 6 %, 18 % and 30 % of the mean maximal voluntary contraction. Doppler measurements at the aortic root and in the femoral artery were utilized to estimate CO and LBF. Oxygen uptake was analyzed breath-by-breath as the difference between inspired and expired oxygen volumes. Within the first 10 s of exercise LBF increased from 400 ml × min^-1 to about 1,000 ml × min^-1 at all exercises intensities. During the subsequent 5 minutes of exercise, LBF decreased to about 800 ml × min^-1 at the lowest intensity. By contrast, it increased to about 1,900 ml × min^-1 at the highest intensity. The changes in CO during exercise were quantitatively identical with the changes in LBF. The present results suggest that the fine adjustment of muscle blood flow and muscle metabolism starts only after a fast and uniform circulatory onresponse. The second component may lead to leg perfusion values above, at or below the initial peak perfusion levels. The off-transients of LBF displayed no comparable fast responses. They were slower than the recovery kinetics of any cardiovascular parameter measured in the present study.

Leg blood flow - muscle perfusion - cardiac output - oxygen uptake - calf exercise

References

• 1 Andersen P, Saltin B. Maximal perfusion of skeletal muscle in man.  J Physiol. 1985;  366 233-249
• 2 Baum K, Eßfeld D, Stegemann J. Changes in extracellular muscle volume affect heart rate and blood pressure responses to static exercise.  Acta Astronautica. 1991;  23 139-147
• 3 Baum K, Selle K, Leyk D, Eßfeld D. Comparison of blood pressure and heart rate to isometric exercise and passive muscle stretch in human.  Eur J Appl Physiol. 1995;  70 240-245
• 4 Casaburi R, Daly J, Hansen J E, Effros R M. Abrupt changes in mixed venous blood gas composition after the onset of exercise.  J Appl Physiol. 1989;  67 1106-1112
• 5 Corcondilas A, Koroxenidis G T, Shepherd J T. Effect of a brief contraction of forearm muscles on forearm blood flow.  J Appl Physiol. 1964;  19 142-148
• 6 DeCort S C, Innes J A, Barstow T J, Guz A. Cardiac output, oxygen consumption and ateriovenous oxygen difference following a sudden rise in exercise levels in humans.  J Physiol. 1991;  441 501-512
• 7 Eriksen M, Waaler B A, Walloe L, Wesche J. Dynamics and dimensions of cardiac output changes in humans at the onset and at the end of moderate rhythmic exercise.  J Physiol. 1990;  426 423-437
• 8 Folkow B, Haglund U, Jodal M, Lundgen O. Blood flow in the calf muscle of man during heavy rhythmic exercise.  Acta Physiol Scand. 1971;  81 157-163
• 9 Geisen L, Leyk D, Hoffmann U, Eßfeld D. Computer-aided evaluation of continuously recorded Doppler measurements during ergometer exercise. In: Blazek V, Schultz-Ehrenburg U (eds) Frontiers in computer-aided visualization of vascular functions. Proceedings of the seventh international symposium CNVD'97 January 10 - 12, 1997, Paris/France. VDI Verlag, Fortschr.-Berichte 1998 Reihe 20/Nr. 263: 183-188
• 10 Gorczynski R J, Klitzman B, Duling B R. Interrelations between contracting striated muscle and precapillary vessels.  Am J Physiol. 1978;  235 504
• 11 Haddy F J, Scott J C. Metabolically linked vasoactive chemicals in local regulation of blood flow.  Physiol Rev. 1968;  48 688-707
• 12 Hughson R L, Schoemaker J K, Tschakovsky M E, Kowalchuk J M. Dependence of muscle V˙O₂ on blood flow dynamics at onset of forearm exercise.  J Appl Physiol. 1996;  81 1619-1626
• 13 Huntsman L L, Stewart D K, Barnes S R, Franklin S B, Colocousis J S, Hessel E A. Non-invasive Doppler determination of cardiac output in man.  Circulation. 1983;  67 593-602
• 14 Laughlin M H. Skeletal muscle blood flow: role of muscle pump in exercise hyperemia.  Am J Physiol. 1987;  253 1004
• 15 Laughlin M H, Armstrong R B. Muscle blood flow during locomotory exercise.  Exerc Sport Sci Rev. 1985;  13 95-136
• 16 Van Leeuwen B E, Barendsen G J, Lubbers J, Barendsen G J, De Pater L. Calf blood flow and posture: Doppler ultrasound measurements during and after exercise.  J Appl Physiol. 1992;  72 1674-1680
• 17 Leyk D, Eßfeld D, Baum K, Stegemann J. Early leg blood flow adjustment during dynamic foot plantar flexions in upright and supine body position.  Int J Sports Med. 1994;  15 451-456
• 18 Leyk D, Eßfeld D, Baum K, Stegemann J. Influence of calf muscle contractions on blood flow parameters measured in the arteria femoralis.  Int J Sports Med. 1992;  13 588-593
• 19 Leyk D, Hoffmann U, Baum K, Eßfeld D. Time courses of cardiac output and oxygen uptake following stepwise increases in exercise intensity.  Int J Sports Med. 1995;  16 357-363
• 20 Leyk D, Hoffmann U, Baum K, Wackerhage H, Eßfeld D. Leg blood flow during slow head-down tilt with and without leg venous congestion.  Eur J Appl Physiol. 1998;  78 538-543
• 21 Loeppky J A, Greene E R, Hoekenga D E, Caprihan A, Luft U C. Beat-by-beat stroke volume assessment by pulsed Doppler in upright and supine exercise.  J Appl Physiol. 1981;  50 1173-1182
• 22 McAllister R M. Endothelial-mediated control of coronary and skeletal muscle blood flow during exercise.  Med Sci Sports Exerc. 1995;  27 1122-1124
• 23 Milnor W R. Hemodynamics. Baltimore; Williams & Wilkins 1989: 58-101
• 24 Mohrman D E, Sparks H V. Myogenic hyperemia following brief tetanus of canine skeletal muscle.  Am J Physiol. 1974;  227 531-535
• 25 Ordway G A, Floyd D L, Longhurst J C, Mitchell J H. Oxygen consumption and hemodynamic responses during graded treadmill exercise in the dog.  J Appl Physiol. 1984;  57 601-607
• 26 Poole D C, Gaesser G A, Hogan M C, Knight D R, Wagner P D. Pulmonary and leg V˙O₂ during submaximal exercise: implications for muscular efficiency.  J Appl Physiol. 1992;  72 805-810
• 27 Radegran G. Ultrasound Doppler estimates of femoral artery blood flow during dynamic knee extensor exercise in humans.  J Appl Physiol. 1997;  83 1383-1388
• 28 Radegran G, Saltin B. Muscle blood flow at onset of dynamic exercise in humans.  Am J Physiol. 1998;  274 322
• 29 Rowell L B. Muscle blood flow in humans: how high can it go?.  Med Sci Sports Exerc. 1988;  20 97-103
• 30 Schmid-Schönbein H, Wells R. Fluid drop-like transition of erythrocytes under shear.  Science. 1969;  165 288-291
• 31 Segal S S, Kurjiaka D T. Coordination of blood flow control in the resistance vasculature of skeletal muscle.  Med Sci Sports Exerc. 1995;  27 1158-1164
• 32 Sheriff D D, Rowell L B, Scher A M. Is rapid rise in vascular conductance at onset of dynamic exercise due to muscle pump.  Am J Physiol. 1995;  265 1234
• 33 Shoemaker J K, Pozeg Z I, Hughson R L. Forearm blood flow by Doppler ultrasound during rest and exercise: tests of day-to-day repeatability.  Med Sci Sports Exerc. 1996;  28 1144-1149
• 34 Smiesko V. Unidirectional rate sensitivity component in local control of vascular tone.  Pflügers Arch. 1971;  327 324-336
• 35 Sparks H V. Effect of local metabolic factors on vascular smooth muscle. In: Bohr DF, Somlyo AP, Sparks HV (eds) Handbook of Physiology. The Cardiovascular System. Bethesda, MD; Am Physiol Soc, Sect. 2 1980 II: 475-513
• 36 Stegall H F. Muscle pumping in the dependent leg.  Circ Res. 1966;  19 180-190
• 37 Stegemann J. Rechnergesteuerte Spiroergometrie nach der Methode der Einzelatemzuganalyse.  Sportarzt Sportmedizin. 1976;  27 1-7
• 38 Toska K, Eriksen M. Peripheral vasoconstriction shortly after onset of moderate exercise in humans.  J Appl Physiol. 1994;  77 1519-1525
• 39 Walloe L, Wesche J. Time course and magnitude of blood flow changes in the human quadriceps muscles during and following rhythmic exercise.  J Physiol. 1988;  405 257-273