出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2015/11/06 10:57:36」(JST)
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Middle age is the period of age beyond young adulthood but before the onset of old age. Various attempts have been made to define this age and it can vary between cultures and historic or previous definitions of this stage of life.
According to Collins Dictionary, this is "... usually considered to occur approximately between the ages of 40 and 60".[1] The current edition of the Oxford English Dictionary gives a similar definition but with a shorter span: "The period of life between young adulthood and old age, now usually regarded as between about forty-five and sixty." The US Census lists the category middle age around 45 to 64, while prominent psychologist Erik Erikson saw it ending a little later and defines middle adulthood as between 40 and 65. The Diagnostic and Statistical Manual of Mental Disorders, the standard diagnostic manual of the American Psychiatric Association, used to define middle age as 40–60, but as of Edition IV (1994) revised the definition upwards to 45–65.
Sociologists and psychologists have made different divisions in human development. Those who are 20-40 years of age are considered to be in young adulthood. Those aged 40-60 are referred to as being in middle adulthood. Late adulthood includes those who are 65 years of age and older.[2]
This time in the lifespan is considered to be the developmental stage of those who are between twenty years-old and forty-years-old. Recent developmental theories have recognized that development occurs across the entire life of a person as they experience changes cognitively, physically, socially, and in personality.[2]
This time period in the life of a person can be referred to as middle age. This time span has been defined as the time between ages forty to sixty years old.[2] Many changes occur between this stage and young adulthood.
There is not a specific age or markers of transitioning between young adulthood to middle adulthood. The maturing process is viewed as completed and gives way to the aging process. The body slows down and the middle aged become more sensitive to diet, substance abuse, stress, and rest. Chronic health problems can become an issue along with disability or disease. Approximately one one centimeter per year of heighth is lost. Emotional responses and retrospection vary from person to person. Experiencing a sense of mortality, sadness or loss is common at this age.[3]
Those in middle adulthood or middle age continue to develop relationships and adapt to the changes in relationships. Changes can be the interacting with growing and grown children and aging parents. Community involvement is fairly typical of this stage of adulthood.[3] Continued development of a satisfying career...
Middle-aged adults begin to show visible signs of aging. Vision usually changes and many who did not need corrective lenses or eyeglasses may find that they need them. Hearing loss begins, especially at the higher frequencies. Height begins with the maximum height from young adulthood but then begins to diminish. This process is more rapid in women who have osteoporosis. Changes occur in the nervous system and reaction time slows. The ability to perform complex tasks remains intact. Those in middle age usually begin to gain weight, 5–10 kg (10–20 lb) and experience a decline in strength and flexibility. Women in late middle age experience menopause. Menopause can have many side effects, some welcome and some not so welcome.[2] Menopause ends natural fertility during this life stage.[4][5] Men also experience physical changes related to sex and reproductive organs but these are not usually as apparent.[2] Both male and female fertility declines with advancing age.[6][7] Advanced maternal age increases the risk of a child being born with some disorders such as Down syndrome. Advanced paternal age significantly increases the risk of miscarriage, as well as possibly slightly increasing the risk of Down syndrome, schizophrenia, autism, decreased intellectual capacity, and bipolar disorder.[8][9][10][11]
Changes occur to skin and hair. Other changes are a decline in physical fitness. Along with an increase in the accumulation of body fat there is a reduction in aerobic performance and a decrease in maximal heart rate. These measurements are generalities and people exhibit these changes at different rates times.[2][12]
In developed countries, yearly mortality begins to increase more noticeably from age 41 onwards, mainly due to age-related health problems such as heart disease and cancer.[13][14] However, the majority of middle-age people in industrialized nations can expect to live into old age. Life expectancy in developing countries is much lower and the risk of death at all ages is higher.[13]
Erik Erikson refers to this period of adulthood as the generatitivity-versus-stagnation stage. Persons in middle adulthood or middle age have some cognitive loss. This loss usually remains unnoticeable because life experiences and strategies are developed to compensate for any decrease in mental abilities.[2]
Marital satisfaction remains but other family relationships can be more difficult. Career satisfaction focuses more on inner satisfaction and contentedness and less on ambition and the desire to 'advance'.[2][3] Even so, career changes often occur. Middle adulthood or middle age can be a time when a person re-examines their life by taking stock, and evaluating their accomplishments. Morality may change and become more conscious. The perception that those in this stage of development or life undergo a 'mid-life' crisis is largely false. This period in life is usually satisfying, tranquil. Personality characteristics remain stable throughout this period.[2]
Those in middle adulthood come to the realization that life will not last forever and that there are limitations to what one might accomplish or achieve. It quite often that a middle aged family member must experience the death of one's parents. This makes the issue of mortality irrefutably. As children grow and leave the one's role as caregiver and provider changes. The relationships in middle adulthood evolve into connections that stable.[3]
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(help)Preceded by Young Adult |
Stages of human development Middle age |
Succeeded by Old age |
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リンク元 | 「middle-aged」「中年」「middle age」 |
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