The endocrinology of aging and its relationship to space physiology.

During the last century the number of people over 65 years of age has increased more than four-fold in the industrialized countries and by the year 2030 might account for 20% of the population. Life expectancy at birth is now about 75 (vs. 47 in 1900) and at 75 is 86 years. The scientific community is thus getting more and more interested in understanding the behavioral and clinical features of centenarians. During aging many endocrine systems undergo anatomic and functional changes at different times and with variable intensities, depending on individual genotypes and phenotypes. The most common finding is impaired anabolism, rather than increased catabolism, so that the hypothesis has been put forward that aging itself stems from the functional deterioration of the endocrine system. From a practical point of view, two main questions arise: (i) to which extent the endocrine glands accelerate physical decay?; (ii) may hormonal replacement ensure health at least longer than nowadays?