|Aging is a biological process under the influence of genetic and pathological factors wh ich can be more or less advanced in different
individuals with the same, chronological age. Silverman (1961) defined age as a three-dimensional phenomenon wherein there is a constant
interaction between chronologie age, physiologic age and psychologic age. Vinton (1964) also points out that there are physiologic,
pathologic, psychologic and sociologic changes which are unique to the latter span of life. These changes are not synonomous with illness as
long as they fall within the physiologic limits of normality. If these limits are exceeded the changes are pathological in character. Age is a phase of life which brings about changed circumstances and a new pattern of life which must be adapted to and accepted. This may
necessitate an invironmental change which causes a loss of friends and social standing and may bring about a feeling of insecurity in some
people, suppressing the incentive to live for the future. To counter these emotions it is imper~tive to create a quality of life in which the aged can be productive within the limits of their physical abilities and which will give them the assurance that they are still needed by society. Life expectancy is determined by the circumstances under which people live. The average age of life expectancy during the Roman period and the Middle Ages was 25 to 30 years; today it is 70 years (Sharry 1974). Nature normally maintains an equilibrium between young and old so that
each can provide for the other's needs. Modern science and technology however have upset that balance and brought about new developments in medicine ich have succeeded in increasin and reducin infant mortality, causing the ectancy explosion. This has brought about a situatiop where 10 million humans are born and only 3 million die every month; thus the inflow into life far exceeds the outflow and there is consequently a global increase of 80 million people per year. At this rate the world population will double itself by the end of this century (Pistorius 1978). Birth control has been encouraged as a counter measure to this and the result has been a marked drop in the birth rate, especially in the more advanced countries of the world. This changing relationship between the birth and death rates is referred to as the population-shift. In the U.S.A. 4% of the total population was over the age of 65 years at the beginning of this century. In 1975 the figure was 10% and at the present rate of population-shift will be 20% by the end of this century (Winkler 1977). In England and Wales 6% of the total population was over the age of 65 years in 1931, 10% in 1951 and 12% in 1962. In Scotland 7% was over the age of 65 years in 1931, 9% in 1951 and 10% in 1962 (Storer 1965). In Canada 4,8% of the total population was over the age of 65 years in 1921 and 7,8% in 1971. The average life expectancy was 50 years in 1900 and 70 years in 1960 (Sherman 1970). This pattern of change is also evident in the Republic of South Atrica but there is a marked variation in the different ethnic groups (White, Asian, Coloureds and Blacks) making up the South African population.