Blood temperature and perfusion to exercising and non-exercising human limbs.
What is the central question of this study? Temperature-sensitive mechanisms are thought to contribute to blood-flow regulation, but the relationship between exercising and non-exercising limb perfusion and blood temperature is not established. What is the main finding and its importance? The close coupling among perfusion, blood temperature and aerobic metabolism in exercising and non-exercising extremities across different exercise modalities and activity levels and the tight association between limb vasodilatation and increases in plasma ATP suggest that both temperature- and metabolism-sensitive mechanisms are important for the control of human limb perfusion, possibly by activating ATP release from the erythrocytes. Temperature-sensitive mechanisms may contribute to blood-flow regulation, but the influence of temperature on perfusion to exercising and non-exercising human limbs is not established. Blood temperature (TB ), blood flow and oxygen uptake (V̇O2) in the legs and arms were measured in 16 healthy humans during 90 min of leg and arm exercise and during exhaustive incremental leg or arm exercise. During prolonged exercise, leg blood flow (LBF) was fourfold higher than arm blood flow (ABF) in association with higher TB and limb V̇O2. Leg and arm vascular conductance during exercise compared with rest was related closely to TB (r(2) = 0.91; P < 0.05), plasma ATP (r(2) = 0.94; P < 0.05) and limb V̇O2 (r(2) = 0.99; P < 0.05). During incremental leg exercise, LBF increased in association with elevations in TB and limb V̇O2, whereas ABF, arm TB and V̇O2 remained largely unchanged. During incremental arm exercise, both ABF and LBF increased in relationship to similar increases in V̇O2. In 12 trained males, increases in femoral TB and LBF during incremental leg exercise were mirrored by similar pulmonary artery TB and cardiac output dynamics, suggesting that processes in active limbs dominate central temperature and perfusion responses. The present data reveal a close coupling among perfusion, TB and aerobic metabolism in exercising and non-exercising extremities and a tight association between limb vasodilatation and increases in plasma ATP. These findings suggest that temperature and V̇O2 contribute to the regulation of limb perfusion through control of intravascular ATP.
Centre for Sports Medicine and Human Performance, Brunel University London, Uxbridge, UK.|The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
José
J
González-Alonso
The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.|Department of Physical Education, and Research Institute of Biomedical and Health Sciences, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
José A L
JA
Calbet
The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.|School of Kinesiology, University of British Columbia, Vancouver, Canada.
Robert
R
Boushel
The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.|Centre for Healthy Ageing, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
Jørn W
JW
Helge
The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
Hans
H
Søndergaard
The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
Thor
T
Munch-Andersen
The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
Gerrit
G
van Hall
The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.|Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark.
Stefan P
SP
Mortensen
The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.|Department of Anaesthesia, Rigshospitalet, University of Copenhagen, Denmark.
Niels H
NH
Secher
D000255:Adenosine Triphosphate / Q000097:blood; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001783:Blood Flow Velocity; D001833:Body Temperature Regulation; D002302:Cardiac Output; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D005268:Femoral Vein / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D035002:Lower Extremity; D008297:Male; D008955:Models, Cardiovascular; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism; D011651:Pulmonary Artery / Q000502:physiology; D012039:Regional Blood Flow; D015398:Signal Transduction; D013350:Subclavian Vein / Q000502:physiology; D013997:Time Factors; D034941:Upper Extremity
D015415:Biomarkers; D000255:Adenosine Triphosphate