Short-term vasomotor adjustments to post immersion dehydration are hindered by natriuretic peptides.

1.6 % and -14.7 ± 1.6 %, respectively; p<0.05). This post-WI decrease was deeper than post DY (p<0.05). Cardiac output (CO) and mean arterial blood pressure were maintained after the two exposures. Plasma levels of noradrenaline, antidiuretic hormone and ANP were twofold higher after WI than after DY (p<0.05). After DY total peripheral resistances (TPR) were increased (p<0.05) and heart rate (HR) was reduced (p<0.05). After WI there was a trend for a decrease in stroke volume (p=0.07) with unchanged TPR and HR, despite more sizeable increases in plasma noradrenaline and vasopressin than after DY. We hypothesized that the higher levels of plasma natriuretic peptides after WI were likely counteracting the dehydration-required vasomotor adjustments.