SKIN MECHANICAL-PROPERTIES PRESENT ADAPTATION TO MANS UPRIGHT POSITION - IN-VIVO STUDIES OF YOUNG AND AGED INDIVIDUALS

In tall animals dependent tissues are stiffer to prevent oedema format ion in the upright posture, but whether the same adaptation is operati ng in man is not known. Skin elasticity and distensibility were measur ed in vivo in 18 young and 15 aged individuals in the morning before g etting up (baseline) and 12 h later. In young individuals skin was sti ffer (less distensible) and less elastic in the acral parts of the ext remities (ankle, forearm). In the evening distensibility and elasticit y of the skin increased. In aged individuals skin was less elastic and no diurnal variability in elasticity and distensibility was detected. We propose that these unique mechanical properties of the acral skin reflect a major role of the integument in the protection against the g ravitational stress and the development of the postural oedema. Altere d skin mechanical properties may contribute to the poor compensation f or gravitational stress in elderly.