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With increasing fat mass, peripheral vascular resistance
actually decreases because, surprisingly, blood flow to adipose tissue is quite high in
comparison to that to skeletal muscle. Thus the increased capillary bed in an expanded
adipose tissue mass reduces total vascular resistance. Blood pressure nevertheless rises
with increasing weight because cardiac output increases in parallel, probably as the
result of sympathetic nervous system activation and increases in blood volume. Thus one
could speculate that the increased cardiovascular risk of hypertension is not so much to
do with elevated blood pressure itself but is the consequence of the increased peripheral
vascular resistance, caused by resistance vessel wall hypertrophy, or by vasoconstriction.
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