José González-Alonso

Limitations to systemic and locomotor limb muscle oxygen delivery and uptake during maximal exercise in humans

Mortensen, Stefan P, Dawson, Ellen A, Yoshiga, Chie C, Dalsgaard, Mads K, Damsgaard, Rasmus, Secher, Niels H, ...

Reductions in systemic and locomotor limb muscle blood flow and O2 delivery limit aerobic capacity in humans. To examine whether O2 delivery limits both aerobic power and capacity, we first measured...

Circulating ATP-induced vasodilatation overrides sympathetic vasoconstrictor activity in human skeletal muscle

Rosenmeier, Jaya B, Hansen, Jim, González-Alonso, José

Despite increases in muscle sympathetic vasoconstrictor activity, skeletal muscle blood flow and O2 delivery increase during exercise in humans in proportion to the local metabolic demand, a...

Brain and central haemodynamics and oxygenation during maximal exercise in humans

González-Alonso, José, Dalsgaard, Mads K, Osada, Takuya, Volianitis, Stefanos, Dawson, Ellen A, Yoshiga, Chie C, ...

During maximal exercise in humans, fatigue is preceded by reductions in systemic and skeletal muscle blood flow, O2 delivery and uptake. Here, we examined whether the uptake of O2 and substrates by...

Limitations to systemic and locomotor limb muscle oxygen delivery and uptake during maximal exercise in humans

Mortensen, Stefan P, Dawson, Ellen A, Yoshiga, Chie C, Dalsgaard, Mads K, Damsgaard, Rasmus, Secher, Niels H, ...

Reductions in systemic and locomotor limb muscle blood flow and O2 delivery limit aerobic capacity in humans. To examine whether O2 delivery limits both aerobic power and capacity, we first measured...

Circulating ATP-induced vasodilatation overrides sympathetic vasoconstrictor activity in human skeletal muscle

Rosenmeier, Jaya B, Hansen, Jim, González-Alonso, José

Despite increases in muscle sympathetic vasoconstrictor activity, skeletal muscle blood flow and O2 delivery increase during exercise in humans in proportion to the local metabolic demand, a...

Brain and central haemodynamics and oxygenation during maximal exercise in humans

González-Alonso, José, Dalsgaard, Mads K, Osada, Takuya, Volianitis, Stefanos, Dawson, Ellen A, Yoshiga, Chie C, ...

During maximal exercise in humans, fatigue is preceded by reductions in systemic and skeletal muscle blood flow, O2 delivery and uptake. Here, we examined whether the uptake of O2 and substrates by...

Erythrocytes and the regulation of human skeletal muscle blood flow and oxygen delivery: role of erythrocyte count and oxygenation state of haemoglobin

González-Alonso, José, Mortensen, Stefan P, Dawson, Ellen A, Secher, Niels H, Damsgaard, Rasmus

Blood flow to dynamically contracting myocytes is regulated to match O2 delivery to metabolic demand. The red blood cell (RBC) itself functions as an O2 sensor, contributing to the control of O2...

Muscle blood flow is reduced with dehydration during prolonged exercise in humans

González-Alonso, José, Calbet, José A L, Nielsen, Bodil

The present study examined whether the blood flow to exercising muscles becomes reduced when cardiac output and systemic vascular conductance decline with dehydration during prolonged exercise in the...

Intravascular ADP and soluble nucleotidases contribute to acute prothrombotic state during vigorous exercise in humans

Yegutkin, Gennady G, Samburski, Sergei S, Mortensen, Stefan P, Jalkanen, Sirpa, González-Alonso, José

Extracellular ATP and ADP trigger vasodilatatory and prothrombotic signalling events in the vasculature. Here, we tested the hypothesis that nucleotide turnover is activated in the bloodstream of...

Metabolic and thermodynamic responses to dehydration-induced reductions in muscle blood flow in exercising humans

González-Alonso, José, Calbet, José A L, Nielsen, Bodil

The present study examined whether reductions in muscle blood flow with exercise-induced dehydration would reduce substrate delivery and metabolite and heat removal to and from active skeletal...

Heat production in human skeletal muscle at the onset of intense dynamic exercise

González-Alonso, José, Quistorff, Bjørn, Krustrup, Peter, Bangsbo, Jens, Saltin, Bengt

We hypothesised that heat production of human skeletal muscle at a given high power output would gradually increase as heat liberation per mole of ATP produced rises when energy is derived from...

Exercising skeletal muscle blood flow in humans responds to reduction in arterial oxyhaemoglobin, but not to altered free oxygen

González-Alonso, José, Richardson, Russell S, Saltin, Bengt

We hypothesised that reducing arterial oxyhaemoglobin (O2Hba) with carbon monoxide (CO) in both normoxia and hyperoxia, or acute hypoxia would cause similar compensatory increases in human skeletal...

Muscle heat production and anaerobic energy turnover during repeated intense dynamic exercise in humans

Krustrup, Peter, González-Alonso, José, Quistorff, Bjørn, Bangsbo, Jens

The aim of the present study was to examine muscle heat production, oxygen uptake and anaerobic energy turnover throughout repeated intense exercise to test the hypotheses that (i) energy turnover is...

Dissociation between muscle tricarboxylic acid cycle pool size and aerobic energy provision during prolonged exercise in humans

Gibala, Martin J, González-Alonso, José, Saltin, Bengt

It has been suggested that a decrease in the total concentration of tricarboxylic acid cycle intermediates (TCAIs) - secondary to a reduction in glycogen availability - compromises oxidative energy...

Human skeletal muscle sympathetic nerve activity, heart rate and limb haemodynamics with reduced blood oxygenation and exercise

Hanada, Akiko, Sander, Mikael, González-Alonso, José

Acute systemic hypoxia causes significant increases in human skeletal muscle sympathetic nerve activity (MSNA), heart rate and ventilation. This phenomenon is thought to be primarily mediated by...

Inhibition of nitric oxide and prostaglandins, but not endothelial-derived hyperpolarizing factors, reduces blood flow and aerobic energy turnover in the exercising human leg

Mortensen, Stefan P, González-Alonso, José, Damsgaard, Rasmus, Saltin, Bengt, Hellsten, Ylva

Prostaglandins, nitric oxide (NO) and endothelial-derived hyperpolarizing factors (EDHFs) are substances that have been proposed to be involved in the regulation of skeletal muscle blood flow during...

The cardiovascular challenge of exercising in the heat

González-Alonso, José, Crandall, Craig G, Johnson, John M

Exercise in the heat can pose a severe challenge to human cardiovascular control, and thus the provision of oxygen to exercising muscles and vital organs, because of enhanced thermoregulatory demand...

Restrictions in systemic and locomotor skeletal muscle perfusion, oxygen supply and during high-intensity whole-body exercise in humans

Mortensen, Stefan P, Damsgaard, Rasmus, Dawson, Ellen A, Secher, Niels H, González-Alonso, José

Perfusion to exercising skeletal muscle is regulated to match O2 delivery to the O2 demand, but this regulation might be compromised during or approaching maximal whole-body exercise as muscle blood...

Haemodynamic responses to exercise, ATP infusion and thigh compression in humans: insight into the role of muscle mechanisms on cardiovascular function

González-Alonso, José, Mortensen, Stefan P, Jeppesen, Tina D, Ali, Leena, Barker, Horace, Damsgaard, Rasmus, ...

The muscle pump and muscle vasodilatory mechanims are thought to play important roles in increasing and maintaining muscle perfusion and cardiac output during exercise, but their actual contributions...

Activation of ATP/UTP-selective receptors increases blood flow and blunts sympathetic vasoconstriction in human skeletal muscle

Rosenmeier, Jaya B, Yegutkin, Gennady G, González-Alonso, José

Sympathetic vasoconstriction is blunted in the vascular beds of contracting skeletal muscle in humans, presumably due to the action of vasoactive metabolites (functional sympatholysis). Recently, we...