Kolegard R, et al. - Cardiac responses were examined by authors to the rotational changes of position in the transversal plane, from supine position (SP) to left lateral position (LLP) while horizontal, and from leaning on the back (HUT-LB) to leaning on the left side (HUT-LL) while tilted 60° head-up from the horizontal. Healthy men underwent 10 min HUT provocations. An enhanced cardiac performance was illustrated in LLP vs SP and in HUT-LL vs HUT-LB. this could be attributed to improved venous return, conceivably, wholly or in part, owing to increased hydrostatic pressure gradients between the caval veins and the heart in the LLP and HUT-LL positions.