Microvascular function is impaired after short-term immobilization in healthy men

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Purpose: We examined whether two weeks of one-leg immobilization would impair leg microvascular function and to what extent a subsequent period of intense aerobic cycle training could restore function.

Methods: Study participants were healthy young males (n=12; 20-24 years of age). Leg microvascular function was determined before the intervention, after the immobilization period and after a four-week exercise training period. Microvascular function was assessed as the vasodilator response to intra-arterial infusion of acetylcholine, sodium nitroprusside and as the vasoconstrictor response to endogenous noradrenaline release induced by tyramine infusion. Vasodilator enzymes as well as pro- and antioxidant enzymes were assessed by protein analysis in skeletal muscle samples; endothelial nitric oxide synthase (eNOS), NADPH oxidase (NOXp67 and NOXgp91) and superoxide dismutase 2 (SOD2).

Results: The acetylcholine induced change in vascular conductance was reduced after the two weeks of immobilization (P=0.003), tended to increase after the subsequent four weeks of exercise training (P=0.061) and was back to baseline levels. Plasma prostacyclin levels in response to acetylcholine infusion were lower after immobilization than before (P=0.041). The changes in vascular conductance with sodium nitroprusside and tyramine were similar during all conditions. Skeletal muscle protein levels of eNOS in the experimental leg were unchanged with immobilization and subsequent training but increased 47% in the control leg with training (P=0.002). NOXp67, NOXgp91 and SOD2 in the experimental leg remained unaltered with immobilization and SOD2 were higher than pre-immobilization after four weeks of training (P<0.001).

Conclusion: The study shows that two weeks of immobilization impairs leg microvascular endothelial function and prostacyclin formation but that four weeks of intense aerobic exercise training restores the function. The underlying mechanism may reside in the prostacyclin system.

Original languageEnglish
JournalMedicine and Science in Sports and Exercise
ISSN0195-9131
DOIs
Publication statusAccepted/In press - 20 Apr 2020

    Research areas

  • Faculty of Science - Inactivity, Exercise training, Skeletal muscle, eNOS, Tyramine

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