Septic shock (associated with relative adrenal insufficiency) is characterized by decreased arterial responsiveness to catecholamines. The association of hydrocortisone and fludrocortisone has demonstrated an improvement in survival in septic shock patients. If hydrocortisone has shown to increase vascular responsiveness, the role of fludrocortisone remains to be elucidated. The purpose of our study is to investigate the effect of a physiological dose of fludrocortisone and/or hydrocortisone on phenylephrine-mean arterial pressure dose-response relationship in healthy volunteers with aldosterone suppression induced by intravenous sodium loading.