Aspectos fisiopatológicos do envelhecimento humano e quedas em idosos

Abstract

The natural aging process involves several biological changes that are inherent to organisms and occur on a gradual basis, due to evolutionary needs. This study focuses on the way age-related anatomical and physiological alterations are closely related to the risk of falls in the elderly. Initially, we show how these alterations, which start at the beginning of adult life, shall only acquire, due to the redundant composition of organic systems, relevance and functional significance when the decline either reaches a considerable extension or is associated with the emergence of pathologies. The speed of such a decline depends on several factors, both genetic and epigenetic ones, which shall determine the organism's response to stimuli. Our goal was to analyze the organic systems closely associated with the risk of falls in physiological aging, such as visual and vestibular system, central nervous system (CNS), cardiovascular system and musculoskeletal and bone systems. Thus, we initially addressed the factors responsible for a reduction in the ability to keep stability and posture, the ability to transpose obstacles, visual acuity, and vestibular function. In particular, we highlighted the alterations of the musculoskeletal and bone systems, which are responsible for locomotion and flexibility. Age-related atrophy and muscular weakness may lead to sarcopenia, a syndrome with serious consequences for the elderly, which results in a significant number of falls and fractures. We also discuss how both structural and functional physiological modifications of the cardiovascular system during aging act as adaptive mechanisms for the compensation of further overload. Some extrinsic factors, such as the use of diuretic and antihypertensive drugs, which are often administrated to elderly affected by cardiovascular diseases, also influence the compromised postural stability, thus contributing to the high prevalence of falls in this population, possibly with serious consequences, including death. Finally, we analyze the neurological alterations observed during life emphasizing aspects related to the system which maintains human balance. In association with motor disturbances, such as in strength and balance, these changes use to lead to disabilities and offer a higher risk of morbidity and mortality among elderly, particularly when those result from falls (English) [ABSTRACT FROM AUTHOR]