American journal of physiology. Heart and circulatory physiology
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Am. J. Physiol. Heart Circ. Physiol. · Feb 2021
Comparative StudyRapid vasodilation within contracted skeletal muscle in humans: new insight from concurrent use of diffuse correlation spectroscopy and Doppler ultrasound.
Previous studies showed that conduit artery blood flow rapidly increases after even a brief contraction of muscles within the dependent limb. Whether this rapid hyperemia occurs within contracted skeletal muscle in humans has yet to be confirmed, however. We therefore used diffuse correlation spectroscopy (DCS) to characterize the rapid hyperemia and vasodilatory responses within the muscle microvasculature induced by single muscle contractions in humans. ⋯ Moreover, the characteristics of the rapid hyperemia and vasodilatory responses of skeletal muscle microvessels differ from those simultaneously evaluated in the upstream conduit artery. NEW & NOTEWORTHY Through the concurrent use of diffuse correlation spectroscopy and Doppler ultrasound, we provide the first evidence in humans that a single brief muscle contraction evokes rapid, intensity-dependent hyperemia within the contracted skeletal muscle microvasculature and the upstream conduit artery. We also show that the magnitude and time course of the contraction-induced rapid hyperemia and vasodilatory responses within skeletal muscle microvessels significantly differ from those in the conduit artery.