Aging-Signs, Causes, Control and Theories About It

The negative physiological changes occurring in the body which weaken the body are called aging. Aging is an inevitable process. Many efforts were made to stop the process of aging of the body but it can not be stopped. Aging is the process that occurs over time as organisms age and becomes less capable of defending themselves from external stresses. It’s not something that comes out of the blue.

Signs Of Aging

There are the following signs of old age. All of them are not present in everyone.

• Loss Of Hair Pigment
• Development of small pigmented areas in the skin of the face and arms
• Dryness and wrinkling  of the skin
• Loss of agility
• Increased weight due to fat deposition
• Poor vision and forgetfulness
• General weakness and decreased body immunity.
• Degeneration of organs and tissues also takes place e.g. arthritis. Arthritis is caused due to degeneration of cartilage. Degeneration and disappearance of the elastic tissue in the tunica media of the blood vessel take place. It causes arteriosclerosis, blood clotting in the coronary arteries.

Causes Of The Process Of Aging

The exact process of aging is still unknown. There may be the following reasons for aging:

A Finite Number Of Divisions

The cells of tissues have only a finite number of mitotic divisions. Thus cells reached this finite number of divisions when the tissue and organ are fully grown. For example, there are fewer nerve cells in old age. So mental activity and memory deteriorate in old age.

Change In Intracellular Substances

Changes in intracellular substances take place during aging. For example, collagen acquires increased cross-linkages in its protein molecules. The elastic tissues lose their elasticity with the passage of time. There is also hardening and loss of resilience in dense connective tissue and cartilage.

Spontaneous Mutations

The spontaneous mutation may result in the loss of cells and degeneration of tissues.

Control Of The Process Of Aging

The process of aging can be slowed down by following measures. These measures can prolong life by an average of 11 years.

• Better nutrition and improved living conditions eg. regular meals, regular exercise, and  Adequate sleep.
• Abstinence from smoking
• Maintaining ideal body weight.

Gerontology

The study of aging is called gerontology. The number of older individuals will rise in the next half-century. The number of people over age 75 will rise from the present 8 million to 14.5 million. The number over age 80 will rise from 5 million to 12 million The maximum human life span is 120-125 years. The present goal of gerontology is not necessarily to increase life span but to increase health span.

Theories About Aging

Here are some theories explaining the causes of aging:

Genetic Theories

There are many theories of aging. One theory holds that the length of a person’s life is genetically programmed and immutable.

People with parents who have lived long lives are likely to live long themselves. This is called parental transference.

As you know, identical twins have life spans more similar in length than do non-twin siblings.

Nongenetic Theories

Some of the theories of aging focus on the idea that age-related changes are the result of cellular or molecular alterations. But the idea that we can slow down the aging process and extend life span is not well supported by current findings.

The aging process is very marked in human development, and there are no indications that cellular processes can be modified as a result of an environmental factor.

Wear-And-Tear Theory

The wear-and-tear theory assumes that everything—from animals and cells to machines—lasts just as long as it should, and only wears out when it fails to do its job. Because this theory doesn’t fit the facts of biology, it doesn’t fit the facts of economics, either. The wear-and-tear theory suggests that the accumulation of toxins, such as free radicals, in cells and tissues is detrimental to the health of cells and contributes to aging.

As humans age and other animals get older, they accumulate insoluble particles that give them a brown or yellowish appearance called “age pigments.” Age pigments accumulate in heart muscle cells and in nerve cells.

Cross-Linking Theory

Tendons, skin, and blood vessels lose elasticity with age. You can maintain their elasticity by exercising regularly.

These cross-linking agents are called collagen linkers, and they’re a group of amino acids that can cross-link collagen molecules and stiffen skin.

Cross-linking is a form of linking two things together. Cross-links between enzymes and other cellular components can change the shape of the molecules, so they’re no longer able to function properly.

Autoimmune Theory

Another theory of aging suggests that immune reactions, normally directed against disease-producing organisms as well as foreign proteins or tissue, begin to attack cells of the individual’s own body.

In other words, the immune system loses its ability to distinguish between self and foreign proteins.

This autoimmune theory of aging is based on clinical evidence but not on experimental evidence.

Latest Research About Aging in Humans

• Scientists used resting-state fMRI data to compare brain states of middle-aged and older adults. Older adults showed reduced access to a metastable substate, which could be stimulated by targeting the precuneus, providing insight for neurostimulation interventions to alleviate cognitive decline in aging brains. [1]
• Scientists propose twelve hallmarks of aging, which are age-associated manifestations that can accelerate aging when experimentally accentuated, but can be decelerated, stopped, or reversed through therapeutic interventions. The hallmarks include genomic instability, telomere attrition, and mitochondrial dysfunction, among others, and are interconnected with each other and with organizational features of spatial compartmentalization, maintenance of homeostasis, and adequate responses to stress, which are hallmarks of health. [2]