Haemodynamic changes in the cardiovascular system during the early phases of orthostasis

In this study, we monitored the changes in arterial blood pressure continuo usly in two groups of Caucasian men during normal passive orthostasis as we ll as reversed passive orthostasis. Group A consisted of a group of 23 youn ger men (16 +/- 0.5 years) and group B consisted of 21 older men (62.9 +/- 2.7 years). The normal passive orthostatic test and the reversed passive or thostatic test were used to induce blood pressure changes. We found that th e temporary and initial changes in blood pressure during the normal and rev ersed orthostatic tests were significantly lower in the older group. Heart rate increases were also lower in the older group. These findings could be explained in terms of a reduced compliance of the thin walled venous blood vessels in the elderly.