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13.70: Adulthood and Aging

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    f-d:aa2ee434b441ece6f0566f9594a6e3c0cd317099e920645b4f33512c IMAGE_TINY IMAGE_TINY.1

    Does getting older have to be a bad thing?

    Being older doesn't necessarily mean being unable to do things and not enjoy life. These seniors look as if they thoroughly enjoy life. And some would say that life begins after all the children have moved out of the house.

    Adulthood and Aging

    Adulthood does not have a definite starting point. A person may be physically mature by age 16 or 17 but not defined as an adult by law until older ages. In the U.S., you can’t join the armed forces or vote until age 18. You can’t buy or use alcohol or take on many legal and financial responsibilities until age 21.

    The video below, 21 Years, is a daily video pictorial of the aging process, from birth to 21 years. Over 7,500 images of the same person have been condensed in a little over 6 minutes.

    Early Adulthood

    Early adulthood coincides with the 20s and early 30s. During early adulthood, people generally form intimate relationships, both in friendship and love. Many people become engaged or marry during this time. Often they are completing their education and becoming established in a career. Health problems in young adults tend to be minor. The most common causes of death are homicides, car crashes, and suicides.

    Middle Adulthood

    Middle adulthood lasts from the mid-30s to the mid-60s. During this stage of life, many people raise a family and strive to attain career goals. They start showing physical signs of aging, such as wrinkles and gray hair. Typically, vision, strength and reaction time start declining. Diseases such as type 2 diabetes, cardiovascular or heart disease, and cancer are often diagnosed during this stage of life. These diseases are also the chief causes of death in middle adulthood.

    Heart Disease

    Heart disease is the number one killer of Americans, and one of the main killers of people the world over. A common cause of heart disease is arteriosclerosis. This is the stiffening or hardening of the arteries that happens, in part, because of growing older. Atherosclerosis, which is the buildup of fatty deposits in the arteries, is another cause of cardiovascular disease. When fat accumulates along the walls of arteries, there is less space for blood to flow. This makes it harder for blood to get to all the parts of the body that need it, including the heart itself. The accumulation of fatty deposits, or plaque, can eventually lead to a heart attack or stroke.

    Other changes to the heart occur during middle adulthood. For example, to help the heart pump blood through stiffer blood vessels, some parts of the heart wall thicken. The size of the four chambers of the heart also change, as do the valves between the chambers. The resting heart rate does not change as you age, but the heart cannot beat as fast when you are physically active or stressed, as it did when you were younger.

    Both genetic and lifestyle choices lead to heart disease. Though you cannot change your genetic background, there are things you can do to slow or prevent the onset of heart disease, especially as you grow older.

    • try to be more physically active,
    • if you smoke, quit,
    • follow a heart healthy diet,
    • keep a healthy weight.

    Old Age

    Old age begins in the mid-60s and lasts until the end of life. Many people over 65 have retired from work, freeing up their time for hobbies, grandchildren, and other interests. Stamina, strength, reflex time, and the senses all decline during old age, and the number of brain cells decreases as well. The immune system becomes less efficient, increasing the risk of serious illnesses such as cancer and pneumonia. Diseases such as Alzheimer’s disease that cause loss of mental function also become more common.

    Causes of Aging

    Why do we decline in all these ways as we age? Generally, it’s because cells stop dividing and die. There are at least two reasons why cells stop dividing:

    1. Cells are programmed to divide only a set number of times.
    2. Mutations accumulate in DNA, and cells with damaged DNA may not divide.


    • During early adulthood, people form intimate relationships and start careers.
    • Serious health problems start showing up in middle adulthood and old age.
    • Aging occurs as cells lose their ability to divide.


    1. When does adulthood begin?
    2. What are the most common causes of death associated with early adulthood?
    3. What diseases are often diagnosed during middle adulthood?
    4. Aging is associated with the death of cells. Give two reasons why cells die.
    5. List three ways to help prevent heart disease as a person ages.

    This page titled 13.70: Adulthood and Aging is shared under a CK-12 license and was authored, remixed, and/or curated by CK-12 Foundation via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

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