Physical changes that accompany aging

During the aging process, every cell and organ in the body undergoes changes. These changes resulted in changes in functionality and appearance.

cellular aging

As cells age, body functions decline. Eventually, the aging cells that make up the body's normal functions die.

The death of aging cells is determined by mechanisms. This program is genetically determined by the cell and initiated by a triggering mechanism. This programmed death is called apoptosis, which is similar to cell "suicide". Cell aging is what triggers apoptosis. Senescent cells must die to make way for new cells. Other triggers of apoptosis include abnormal cell numbers or damaged cells.

Some senescent cells die because they can only divide a limited number of times. This limitation is genetically determined. When a cell can no longer divide, they grow larger and larger, survive for a certain period of time, and eventually die. The mechanism that limits cell division lies in tiny structures called telomeres. During the early stages of cell division, telomeres are used to move genetic material. Each time a cell divides, telomeres shorten. Every time a cell divides, the telomeres shorten. Eventually, the telomeres become so tiny that the cell can no longer divide. When cells stop dividing, it's called senescence.

Sometimes cells die directly after being damaged. Harmful substances can damage cells, such as radiation, sunlight, and chemotherapy drugs. Certain by-products of normal activities may also damage cells. When cells produce energy, they produce these by-products called free radicals.

do you know……

Disease causes more loss of function than aging.

organ aging

The functional status of organs depends on the functional status of cells. The function of aging cells declines. Moreover, for some organs, after cell death there are no new cells to replace them, so the number of cells decreases. The number of cells in the testicles, ovaries, liver and kidneys decreases significantly with aging. When the number of cells decreases to a certain level, organ function will be affected. Therefore, the functions of most organs decline as the body ages. However, not all organs lose large numbers of cells. The brain is a classic example. Healthy older adults do not lose many brain cells. Severe loss is mostly seen in people who have had a stroke or have a disease (neurodegenerative disease) that causes progressive loss of nerve cells (such as Alzheimer's disease or Parkinson's disease).

The first signs of aging often appear in the musculoskeletal system. Eye and ear function also begin to change as early as middle age. Most internal functions also decline with age. Most functions of the human body reach their peak before the age of 30, and then quickly decline gradually and continuously. Of course, most organ functions are still very "competent" because the total capacity of organ functions is greater than the body's needs from the beginning. This is called functional reserve. For example, if half of the liver is damaged, the remaining liver tissue can maintain normal liver function. Therefore, disease can bring about more loss of function than normal aging.

Even so, functional decline means that older adults are less able to cope with various stressors, including heavy physical labor, drastic changes in environmental temperature, and illness. It also makes the elderly more susceptible to drug side effects. Some organs are more prone to problems than others when dealing with stress. These organs include cardiovascular, urinary organs (such as kidneys), and the brain.

bones and joints

(See also Effects of aging on the musculoskeletal system.)

Bone density will decrease. Moderate loss of bone density is called osteopenia, while severe loss of bone density (including loss of bone density leading to fractures) is called osteoporosis. In people with osteoporosis, bones become fragile and more likely to fracture. In women, falling estrogen levels after menopause can accelerate the loss of bone density. During the normal process of bone formation, degradation, and remodeling, estrogen helps prevent excessive bone degradation.

Bones become porous, in part due to a decrease in calcium (which makes bones strong). A decrease in total calcium means the body is absorbing less calcium from the diet. At the same time, levels of vitamin D (which helps the body improve calcium utilization) also decrease slightly. Some bones are more fragile than others. These changes occur most often in the thigh bone (femur) at the hip, the forearm bones (radius, ulna) at the wrist, and the bones in the spine (vertebrae).

If these changes occur in the upper part of the spine, they can cause the head to tilt forward and put pressure on the pharynx. As a result, swallowing becomes difficult and choking is more likely to occur. The density of the vertebrae decreases, and the cushioning tissue between them (the intervertebral discs) loses moisture and becomes thinner, causing the spine to shorten. Therefore, many elderly people become shorter.

The cartilage between joints becomes thinner due to years of wear and tear, the joint surface is not as smooth as before, and the entire joint is more susceptible to injury. The joint surfaces cannot slide as well as they used to, and the joints are more susceptible to injury. Cartilage damage from lifelong use of joints or repeated injuries often leads to osteoarthritis, an extremely common disease in older age.

Ligaments (which hold joints together) and tendons (which attach muscles to bones) lose their elasticity, and the joints become tight or stiff. These organizations also become vulnerable. As a result, most elderly people experience reduced flexibility. Ligaments and tendons are more likely to tear, and when they do, they are slow to heal. All of these changes are due to reduced activity of the cells that make up these ligaments and tendons.

muscle and fat

Decreases in musculature (muscle mass) and muscle strength begin around age 30 and continue throughout life. Loss of total muscle mass is partly due to lack of exercise, but also due to decreased levels of growth hormone and testosterone (both of which promote muscle development). The muscle loses its ability to contract quickly because fast-twitch (fast-twitch) muscle fibers lose more weight than slow-twitch (slow-twitch) muscle fibers. However, over the course of adult life, the effects of aging can reduce muscle mass and strength by approximately 10% to 15%. In the absence of disease, most of this 10 to 15 percent loss can be prevented through regular exercise. More severe forms of muscle loss (also called sarcopenia, which literally means muscle loss) are caused by disease or extreme inactivity, not just aging.

The vast majority of older adults maintain sufficient muscle mass and strength to perform necessary physiological functions. Many older people are still very fit. They participate in sports competitions and engage in high-intensity physical activity. However, even the healthiest people will notice decline as they age.

do you know……

To make up for the muscle mass lost during a day of strict bed rest, older adults need to exercise for two weeks.

Routine muscle-strengthening exercise (resistance training) can partially overcome or significantly delay the loss of muscle mass and strength. In exercises that target muscle strength, the muscles contract against the resistance of gravity (push-ups or sit-ups), weight, or the elasticity of a rubber band. This exercise will increase muscle mass and muscle strength if done regularly. On the contrary, resting state, especially bed rest during illness, can greatly accelerate the loss of muscle mass. In the resting state, older adults are more likely to lose muscle mass and strength than younger adults. For example, in order to make up for the muscle mass lost during a day of strict bed rest, the elderly need to exercise for two weeks.

By the age of 75, the amount of body fat is twice as high as in youth. Too much fat increases the risk of health problems, such as diabetes. Fat distribution also changes, altering the shape of the body. A scientific diet and regular exercise for the elderly can prevent body fat from increasing too quickly.

Eye

(See also Effects of Age on Eyes.)

The following changes occur during the aging process:

The lens becomes hard and the ability to focus on close objects decreases.

The lens becomes cloudy, making it difficult to see in dim light.

When light changes, the pupil's reaction slows down.

Yellow staining of the lens, affecting color recognition.

The number of optic nerve cells decreases, affecting visual depth perception.

The secretion of tear glands is reduced and the eyes are dry.

Visual changes are often considered the first signs of aging.

Changes to the lens can cause a number of conditions:

Impaired near vision: Starting from the age of 40, many people find that it becomes increasingly difficult to see objects within 60 centimeters. This vision change is called presbyopia and is caused by the hardening of the lens. Normally, the lens focuses by changing its shape. A hardened lens makes it difficult to focus on close objects. Eventually, almost everyone will need professional glasses to help with reading. These glasses may be bifocals (glasses for both nearsightedness and farsightedness) or varifocals (having lenses that can be zoomed).

Higher requirements for light brightness: As age continues to grow, the transmittance of the lens decreases, making it difficult to see objects clearly in low light. Clouding of the lens means that less light passes through it and reaches the retina at the back of the eye. Furthermore, the sensitivity of the retina, which contains cells that sense light, also decreases. So reading requires brighter light. Generally speaking, reading requires three times the brightness of light at a 60-year-old than a 20-year-old.

Changes in color perception: This change is caused in part by jaundice of the lens. The colors are no longer bright and the differences between the different colors are less obvious. The blue turned gray, as if it had been washed away. This situation will not have a major impact on most people. But older people will have a hard time reading black letters on blue paper or reading blue letters.

The pupil's light response also becomes dull. Pupils dilate or constrict to regulate how much light comes in. Sluggish pupillary reaction can make older adults unable to see clearly when they first enter a dark room. Or become temporarily blinded when suddenly entering a bright environment. Older people may also be more sensitive to glare. Older people are more sensitive to bright light, but this sensitivity is mostly caused by lens opacity and cataracts.

do you know……

Reading requires three times the brightness of light at age 60 compared to age 20.

Details, including shadows and tones, become more difficult to discern, possibly due to a reduction in visual nerve cells. This may be caused by a reduction in the number of nerve cells responsible for carrying visual signals from the eyes to the brain. This change affects estimates of visual depth and thus distance judgments.

Older people often see small black dots floating around in their vision. These little black dots are called floaters, which are small fragments of normal fluid in the eye that have solidified. This phenomenon is called "floaters". Floaters do not seriously affect vision unless the amount of debris increases significantly over a short period of time.

Eyes become increasingly dry. This is because the number of cells that produce lubricating fluid decreases. Tear secretion is also reduced.

The appearance of the eyes also shows the following changes:

The white part of the eye (sclera) turns slightly yellow or slightly brown. This is caused by years of exposure to UV rays, wind and dust.

Scattered pigment spots will appear on the sclera, especially in people with dark skin.

A gray-white ring will appear on the surface of the eyeball, called the "senile ring". This ring is caused by calcium and lipid deposition and generally does not affect vision. This ring is caused by calcium and cholesterol salt deposits. Will not affect vision.

The lower eyelid droops and separates from the eyeball due to laxity of the muscles around the eye and extension of the tendons. This condition (called ectropion) affects the lubrication of the eyeball, causing dry eye syndrome.

Loss of fat around the eyes causes enophthalmos.

Ear

(See also Effects of Aging on the Ear, Nose, and Throat.)

Most changes in hearing are not just caused by aging; noise is likely to have just as much of an impact (see also hearing loss). Prolonged exposure to loud noise can damage your ear's hearing. However, there are some hearing changes that occur with age, regardless of noise exposure.

It's best to see your doctor to determine if your hearing loss is caused by cerumen (earwax) impaction, as this is easily treated.

As we age, it becomes harder to hear high-pitched tones. This change is considered age-related hearing loss (presbycusis). For example, the sound of the violin is no longer clear.

do you know……

For older people with hearing difficulties, articulating words clearly is more effective than speaking loudly.

High-pitched pitches—more difficult for older people to listen to.

The most frustrating consequence of presbycusis is that it is more difficult to hear words. Therefore, the elderly may think that others are mumbling to themselves. Even if other people are talking loudly, it is still difficult for the elderly to hear what others are saying. The reason why the above situation occurs is that many consonants (such as k, t, s, p and ch) are high-pitched sounds, and consonants are an important part of how people distinguish words. Vowel syllables are low-pitched and easier to hear. Therefore, if you want the elderly to hear clearly, clear pronunciation is more effective than just raising the volume. To help older adults hear clearly, clear pronunciation is more effective than simply raising the volume. Hearing women and children is more difficult than hearing men because most women and children have high-pitched voices. Slowly, it became difficult to hear even low-pitched voices.

Many older adults develop hearing impairment in noisy environments.

Thick hair will grow in the ears.

Mouth and nose

(See also Effects of Aging on the Mouth and Teeth and Effects of Aging on the Ears, Nose, and Throat.)

Typically, people begin to experience a decline in their sense of taste and smell around age 50. People need both senses to enjoy the full flavor in food. The tongue can detect five basic tastes: sweet, sour, bitter, salty, and a taste called "umami" (generally described as "spicy" or "savory"). The sense of smell can distinguish more subtle flavors or blends of flavors (such as cherry).

The number and sensitivity of taste buds at the base of the tongue decrease with age. But compared to sour and bitter, it affects the perception of sweet and salty more. The reduced sense of smell is caused by thinning and drying of the nasal mucosa and degeneration of peripheral nerves in the nasal cavity. Of course, this change is mild and usually only affects fine sense of smell. As a result of the changes described above, many foods appear to have become bitter.

The mouth feels dry more and more often, in part because saliva is reduced, and dry mouth further reduces taste. Dry mouth further reduces taste.

As we age, our gums gradually recede. The gums gradually recede, exposing the deep parts of the teeth to food particles and bacteria. The enamel is obviously worn. These changes combined with a dry mouth make teeth more susceptible to cavities and erosion (caries), making teeth more susceptible to loss.

As we age, the nose tends to become longer and the tip of the nose droops.

Thick hair may grow in the nose and on the upper lip and chin.

skin

(See also Effects of Age on Skin.)

The skin gradually becomes thinner, dries out, loses elasticity and develops fine wrinkles. Years of exposure