Physiological effects of sleeping with the head of the bed elevated 18 in. in young healthy volunteers.

BACKGROUND: Sleeping with the head of bed tilted upwards (SHU) is recommended as a treatment of orthostatic hypotension though the supporting evidence is weak. AIM: To investigate the physiological effects of SHU amongst a group of young healthy volunteers. METHODS: Twenty-nine volunteers, mean age 22 years, underwent 1-week of SHU at 18-in. elevation. Before and after hemodynamic and non-haemodynamic parameters were recorded. RESULTS: After SHU, there were reductions in the systolic blood pressure drop on standing, upright total peripheral resistance, haemoglobin, nocturnal urinary volume, orthostatic dizziness and increases in weight, standing cardiac output and ankle circumference. There were no differences in heart rate, stroke volume, renin, aldosterone, pro-atrial natriuretic peptide or 24-h blood pressure. CONCLUSIONS: In these healthy subjects, SHU for 1 week had a nocturnal antidiuretic effect with both intra- and extra-vascular accumulation of fluid and was associated with reduced postural drop in SBP and improved orthostatic tolerance.