Izvorni znanstveni članak
Is there any connection between working ability and aging?
Zijad Duraković
Sažetak
Although the definitions of the so-called older age are based on the chronological age of 65 years and over, aging is the process which starts with the 30th year of life. At the beginning occur changes in the organ functions, followed by anatomical changes as well. Some organs age faster, some slower. For example, kidneys decrease for one third, lungs do not change, liver shrinks a little, prostate increases twice. Muscle mass in men aged 65 is on average 12 kilos less than in the so-called middle age, and in women it is approximately 5 kilos less. In the heart the amount of connective tissue increases, lipofuscin is deposited in cardiac muscle, the strength of which is decreasing. In the respiratory tract the number of pathways cilia decreases, along with the alveolar surface, muscles involved in breathing change, lung elasticity is also diminished. But, in regard with the previous body capacity, “physiological aging” can be divided into three groups: the “older” elderly have the highest functional capacity of 2-3 MET (MET= metabolic unit, i.e. the oxygen consumption of 3.5 ml/kg body mass in a minute), the “younger” elderly are the persons of older age having maximal functional capacity of 5-7 MET, while the “sport” elderly have the functional capacity of 9-10 MET, disregarding chronological age.
Connective tissues change, become fragile. Digestive system diminishe motility and function, as renal system. The brain weight diminishes for approximately 7% compared to younger age. In temporal gyrus and area striata even 20-40% of cells are being lost, vacuolar and neuroaxonal degeneration occurs, lipofuscin is being accumulated. The brain blood flow, which is in normal conditions 50-60 ml/min/100g of tissue, with the increase of biological age decreases to about 40 ml/min/100 g of tissue. However, this usually is not the consequence of biological age but of disease. The arbitrary limit of the so-called older age starting with the 65th year of life is not marked by anything, there are no measurable biological proofs for it. The changes in the organism during the so-called aging are individual. The functional capacity of an organism, both physical and intellectual, must be evaluated individually.
Ključne riječi
Hrčak ID:
7719
URI
Datum izdavanja:
25.11.2006.
Posjeta: 2.814 *