Men who are highly trained in endurance exercise have the same blood flow and vessel dilation in their thighs after eating a meal as men with average fitness, even though their bodies respond better...
Mechanism
Synthesis from 1 study
Regular endurance training makes the brain more responsive to insulin after eating, which turns up the activity of nerves that tighten blood vessels. This prevents the leg arteries from widening, even though the body is using insulin more efficiently — so blood flow doesn’t increase despite better...
Most probable mechanism
When someone trains regularly for endurance, their brain becomes more sensitive to insulin after eating. This causes nerves that tighten blood vessels to become more active, which prevents the large leg arteries from opening up wider, even though the body is using insulin better overall.
Chronic endurance training improves the transport of insulin across the blood-brain barrier, increasing its concentration in the hypothalamus
Elevated insulin in the hypothalamus activates insulin receptors on neurons, triggering intracellular signaling through PI3K and MAPK pathways
Activated hypothalamic neurons increase efferent sympathetic nerve firing to skeletal muscle vasculature
Increased sympathetic nerve activity causes vasoconstriction in the femoral artery, counteracting insulin-mediated vasodilatory signals
The net effect is no increase in femoral artery blood flow or vascular conductance despite improved systemic insulin sensitivity
Evidence from Studies
Supporting (1)
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Influence of endurance training on central sympathetic outflow to skeletal muscle in response to a mixed meal.
Contradicting (0)
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