Health in Late Adulthood: Primary Aging

Diana Lang; Nick Cone; Laura Overstreet; Martha Lally; and Suzanne Valentine-French

Normal Aging

The Baltimore Longitudinal Study on Aging (BLSA)[1] began in 1958 and has traced the aging process in 1,400 people from age 20 to 90. Researchers from the BLSA have found that the aging process varies significantly from individual to individual and from one organ system to another. Kidney function may deteriorate earlier in some individuals.[2]

Bone strength declines more rapidly in others. Much of this is determined by genetics, lifestyle, and disease. However, some generalizations about the aging process have been found:

  • Heart muscles thicken with age
  • Arteries become less flexible
  • Lung capacity diminishes
  • Brain cells lose some functioning but new neurons can also be produced
  • Kidneys become less efficient in removing waste from the blood
  • The bladder loses its ability to store urine
  • Body fat stabilizes and then declines
  • Muscle mass is lost without exercise
  • Bone mineral is lost. Weight bearing exercise slows this down.
Link to Learning

Watch this video clip from the National Institute of Health as it explains the research involved in the Baltimore Longitudinal Study on Aging. You’ll see some of the tests done on individuals, including measurements on energy expenditure, strength, proprioception, and brain imaging and scans. Watch the The Baltimore Longitudinal Study of Aging (BLSA).

younger hands holding an aged hand.
Figure 1. Primary aging includes inevitable changes such as skin that becomes more wrinkled and less elastic. (Image Source: PxHere)

Primary and Secondary Aging

Healthcare providers need to be aware of which aspects of aging are reversible and which ones are inevitable. By keeping this distinction in mind, caregivers may be more objective and accurate when diagnosing and treating older patients. And a positive attitude can go a long way toward motivating patients to stick with a health regime. Unfortunately, stereotypes can lead to misdiagnosis. For example, it is estimated that about 10 percent of older patients diagnosed with dementia are actually depressed or suffering from some other psychological illness.[3] The failure to recognize and treat psychological problems in older patients may be one consequence of such stereotypes.

Primary Aging

Senescence, or biological aging, is the gradual deterioration of functional characteristics. It is the process by which cells irreversibly stop dividing and enter a state of permanent growth arrest without undergoing cell death. This process is also referred to as primary aging and thus, refers to the inevitable changes associated with aging (Figure 1).[4] These changes include changes in the skin and hair, height and weight, hearing loss, and eye disease. However, some of these changes can be reduced by limiting exposure to the sun, eating a nutritious diet, and exercising.

Skin and hair change with age. The skin becomes drier, thinner, and less elastic during the aging process. Scars and imperfections become more noticeable as fewer cells grow underneath the surface of the skin. Exposure to the sun, or photoaging, accelerates these changes. Graying hair is inevitable, and hair loss all over the body becomes more prevalent.

Height and weight vary with age. Older people are more than an inch shorter than they were during early adulthood.[5] This is thought to be due to a settling of the vertebrae and a lack of muscle strength in the back. Older people weigh less than they did in mid-life. Bones lose density and can become brittle. This is especially prevalent in women. However, weight training can help increase bone density after just a few weeks of training.

Muscle loss occurs in late adulthood and is most noticeable in men as they lose muscle mass. Maintaining strong leg and heart muscles is important for independence. Weight-lifting, walking, swimming, or engaging in other cardiovascular and weight bearing exercises can help strengthen the muscles and prevent atrophy.


Some typical vision issues that arise along with aging include:

  • Lens becomes less transparent and the pupils shrink.
  • The optic nerve becomes less efficient.
  • Distant objects become less acute.
  • Loss of peripheral vision (the size of the visual field decreases by approximately one to three degrees per decade of life.)[6]
  • More light is needed to see and it takes longer to adjust to a change from light to darkness and vice versa.
  • Driving at night becomes more challenging.
  • Reading becomes more of a strain and eye strain occurs more easily.

The majority of people over 65 have some difficulty with vision, but most is easily corrected with prescriptive lenses. Three percent of those 65 to 74 and 8 percent of those 75 and older have hearing or vision limitations that hinder activity. The most common causes of vision loss or impairment are glaucoma, cataracts, age-related macular degeneration, and diabetic retinopathy.[7]

  • Glaucoma occurs when pressure in the fluid of the eye increases, either because the fluid cannot drain properly or because too much fluid is produced. Glaucoma can be corrected with drugs or surgery. It must be detected early enough.
  • Cataracts are cloudy or opaque areas of the lens of the eye that interfere with passing light, frequently develop. Cataracts can be surgically removed or intraocular lens implants can replace old lenses.
  • Macular degeneration is the most common cause of blindness in people over the age of 60. Age-related macular degeneration (AMD) affects the macula, a yellowish area of the eye located near the retina at which visual perception is most acute. A diet rich in antioxidant vitamins (C, E, and A) can reduce the risk of this disease.
  • Diabetic retinopathy, also known as diabetic eye disease, is a medical condition in which damage occurs to the retina due to diabetes mellitus. It is a leading cause of blindnessThere are three major treatments for diabetic retinopathy, which are very effective in reducing vision loss from this disease: laser photocoagulation, medications, surgery.


Hearing Loss, is experienced by 25% of people between ages 65 and 74, then by 50% of people above age 75.[8] Among those who are in nursing homes, rates are even higher. Older adults are more likely to seek help with vision impairment than with hearing loss, perhaps due to the stereotype that older people who have difficulty hearing are also less mentally alert.

Conductive hearing loss may occur because of age, genetic predisposition, or environmental effects, including persistent exposure to extreme noise over the course of our lifetime, certain illnesses, or damage due to toxins. Conductive hearing loss involves structural damage to the ear such as failure in the vibration of the eardrum and/or movement of the ossicles (the three bones in our middle ear). Given the mechanical nature by which the sound wave stimulus is transmitted from the eardrum through the ossicles to the oval window of the cochlea, some degree of hearing loss is inevitable. These problems are often dealt with through devices like hearing aids that amplify incoming sound waves to make vibration of the eardrum and movement of the ossicles more likely to occur.

When the hearing problem is associated with a failure to transmit neural signals from the cochlea to the brain, it is called sensorineural hearing loss. This type of loss accelerates with age and can be caused by prolonged exposure to loud noises, which causes damage to the hair cells within the cochlea. Presbycusis is age-related sensorineural hearing loss resulting from degeneration of the cochlea or associated structures of the inner ear or auditory nerves. The hearing loss is most marked at higher frequencies. Presbycusis is the second most common illness next to arthritis in aged people.

One disease that results in sensorineural hearing loss is Ménière’s disease. Although not well understood, Ménière’s disease results in a degeneration of inner ear structures that can lead to hearing loss, tinnitus (constant ringing or buzzing), vertigo (a sense of spinning), and an increase in pressure within the inner ear.[9] This kind of loss cannot be treated with hearing aids, but some individuals might be candidates for a cochlear implant as a treatment option. Cochlear implants are electronic devices consisting of a microphone, a speech processor, and an electrode array. The device receives incoming sound information and directly stimulates the auditory nerve to transmit information to the brain.

Being unable to hear causes people to withdraw from conversation and others to ignore them or shout. Unfortunately, shouting is usually high pitched and can be harder to hear than lower tones. The speaker may also begin to use a patronizing form of ‘baby talk’ known as elderspeak.[10] This language reflects the stereotypes of older adults as being dependent, demented, and childlike. Hearing loss is more prevalent in men than women. And it is experienced by more white, non-Hispanics than by Black men and women. Smoking, middle ear infections, and exposure to loud noises increase hearing loss.

Nutrition and Aging Research

The Jean Mayer Human Nutrition Research Center on Aging (HNRCA), located in Boston, Massachusetts, is one of six human nutrition research centers in the United States supported by the United States Department of Agriculture and Agricultural Research Service. The goal of the HNRCA, which is managed by Tufts University, is to explore the relationship between nutrition, physical activity, and healthy and active aging.

The HNRCA has made significant contributions to U.S. and international nutritional and physical activity recommendations, public policy, and clinical healthcare. These contributions include advancements in the knowledge of the role of dietary calcium and vitamin D in promoting nutrition and bone health, the role of nutrients in maintaining the optimal immune response, the prevention of infectious diseases, the role of diet in prevention of cancer, obesity research, modifications to the Food Guide Pyramid, contribution to USDA nutrient data bank, advancements in the study of sarcopenia, heart disease, vision, brain and cognitive function, front of packaging food labeling initiatives, and research of how genetic factors impact predisposition to weight gain and various health indicators. Research clusters within the HNRCA address four specific strategic areas: 1) cancer, 2) cardiovascular disease, 3) inflammation, immunity, and infectious disease and 4) obesity.

Video Example

Research done by T. Colin Campbell M.D., Michael Greger M.D., Neal Bernard M.D. and others have demonstrated the impact of diet upon longevity and quality of life. As discussed in the video below, consumption of less animal based protein has been linked with the slowing of degradation of function which was traditionally seen as part of the normal aging process.

You can view the transcript for “Caloric Restriction vs. Animal Protein Restriction” here (opens in new window).

Primary aging can be compensated for through exercise, corrective lenses, nutrition, and hearing aids. Just as important, by reducing stereotypes about aging, people of age can maintain self-respect, recognize their own strengths, and count on receiving the respect and social inclusion they deserve.

Try It

Sensory Changes in Late Adulthood


In late adulthood, all the senses show signs of decline, especially among the oldest-old. In the last chapter, you read about the visual changes that were beginning in middle adulthood, such as presbyopia, dry eyes, and problems seeing in dimmer light. By later adulthood these changes are much more common. Three serious eyes diseases are more common in older adults: Cataracts, macular degeneration, and glaucoma. Only the first can be effectively cured in most people.

Cataracts are a clouding of the lens of the eye (Figure 2). The lens of the eye is made up of mostly water and protein. The protein is precisely arranged to keep the lens clear, but with age some of the protein starts to clump. As more of the protein clumps together the clarity of the lens is reduced. While some adults in middle adulthood may show signs of cloudiness in the lens, the area affected is usually small enough to not interfere with vision. More people have problems with cataracts after age 60[11] and by age 75, 70% of adults will have problems with cataracts.[12] Cataracts also cause a discoloration of the lens, tinting it more yellow and then brown, which can interfere with the ability to distinguish colors such as black, brown, dark blue, or dark purple.

Risk factors besides age include certain health problems such as diabetes, high blood pressure, and obesity, behavioral factors such as smoking, other environmental factors such as prolonged exposure to ultraviolet sunlight, previous trauma to the eye, long- term use of steroid medication, and a family history of cataracts.[13][14] Cataracts are treated by removing and replacing the lens of the eye with a synthetic lens. In developed countries, such as the United States, cataracts can be easily treated with surgery. However, in developing countries, access to such operations are limited, making cataracts the leading cause of blindness in late adulthood in Third World nations. [15]

Older adults are also more likely to develop age-related macular degeneration, which is the loss of clarity in the center field of vision, due to the deterioration of the macula, the center of the retina (Figure 2). Macular degeneration does not usually cause total vision loss, but the loss of the central field of vision can greatly impair day-to-day functioning. There are two types of macular degeneration: dry and wet.

The risk factors for macular degeneration include smoking, which doubles your risk;[16] race, as it is more common among Caucasians than African Americans or Hispanics/Latinos; high cholesterol; and a family history of macular degeneration.[17] At least 20 different genes have been related to this eye disease, but there is no simple genetic test to determine your risk, despite claims by some genetic testing companies.[18]

Figure 2 Normal Vision vs. Cataracts, Macular Degeneration and Glaucoma (Image adapted by Martha Lally and Valentine French, original source: Wikimedia Commons)

A third vision problem that increases with age is glaucoma, which is the loss of peripheral vision, frequently due to a buildup of fluid in eye that damages the optic nerve. As you age the pressure in the eye may increase causing damage to the optic nerve. The exterior of the optic nerve receives input from retinal cells on the periphery, and as glaucoma progresses more and more of the peripheral visual field deteriorates toward the central field of vision. In the advanced stages of glaucoma, a person can lose their sight. Fortunately, glaucoma tends to progresses slowly.[19] Glaucoma is the most common cause of blindness in the U.S.[20] African Americans over age 40, and everyone else over age 60 has a higher risk for glaucoma. Those with diabetes, and with a family history of glaucoma also have a higher risk.[21] There is no cure for glaucoma, but its rate of progression can be slowed, especially with early diagnosis. Routine eye exams to measure eye pressure and examination of the optic nerve can detect both the risk and presence of glaucoma.[22] Those with elevated eye pressure are given medicated eye drops.


Our hearing declines both in terms of the frequencies of sound we can detect and the intensity of sound needed to hear as we age. These changes continue in late adulthood. Almost 1 in 4 adults aged 65 to 74 and 1 in 2 aged 75 and older have disabling hearing loss.[23] Some common signs of hearing loss include:

  • Having trouble hearing over the telephone
  • Finding it hard to follow conversations when two or more people are talking
  • Often asking people to repeat what they are saying
  • Needing to turn up the TV volume so loud that others complain
  • Having a problem hearing because of background noise
  • Thinking that others seem to mumble
  • Not being able to understand when those with quieter voices are speaking to you

Presbycusis is a common form of hearing loss in late adulthood that results in a gradual loss of hearing. It runs in families and affects hearing in both ears.[24] Older adults may also notice tinnitus, a ringing, hissing, or roaring sound in the ears. The exact cause of tinnitus is unknown, although it can be related to hypertension and allergies. It may come and go or persist and get worse over time.[25] The incidence of both presbycusis and tinnitus increase with age and males have higher rates of both around the world.[26] Your auditory system has two jobs: To help you to hear, and to help you maintain balance. Your balance is controlled by the brain receiving information from the shifting of hair cells in the inner ear about the position and orientation of the body. With age this function of the inner ear declines which can lead to problems with balance when sitting, standing, or moving.[27]

Taste and Smell

Our sense of taste and smell are part of our chemical sensing system. Our sense of taste, or gustation, appears to age well. Normal taste occurs when molecules that are released by chewing food stimulate taste buds along the tongue, the roof of the mouth, and in the lining of the throat. These cells send messages to the brain, where specific tastes are identified. After age 50 we start to lose some of these sensory cells. Most people do not notice any changes in taste until ones 60s.[28] Given that the loss of taste buds is very gradual, even in late adulthood, many people are often surprised that their loss of taste is most likely the result of a loss of smell.

Table 1. Types of Smell Disorders, adapted from NIH Senior Health: Problems with Smell
Disorder Description
Presbyosmia Smell loss due to aging
Hyposmia Loss of only certain odors
Anosmia Total loss of smell
Dysosmia Change in the perception of odors. Odors are distorted.
Phantosmia Smelling odors that are not present.

Our sense of smell, or olfaction, decreases more with age, and problems with the sense of smell are more common in men than in women. Almost 1 in 4 males in their 60s have a disorder with the sense of smell, while only 1 in 10 women do.[29] This loss of smell due to aging is called presbyosmia. Olfactory cells are located in a small area high in the nasal cavity. These cells are stimulated by two pathways; when we inhale through the nose, or via the connection between the nose and the throat when we chew and digest food. It is a problem with this second pathway that explains why some foods such as chocolate or coffee seem tasteless when we have a head cold. There are several types of loss of smell. Total loss of smell, or anosmia, is extremely rare (Table 1).

Problems with our chemical senses can be linked to other serious medical conditions such as Parkinson’s, Alzheimer’s, or multiple sclerosis.[30] Any sudden change should be checked out. Loss of smell can change a person’s diet, with either a loss of enjoyment of food and eating too little for balanced nutrition, or adding sugar and salt to foods that are becoming blander to the palette.

Touch and Pain

Research has found that with age, people may experience reduced or changed sensations of vibration, cold, heat, pressure, or pain.[31] Many of these changes are also aligned with a number of medical conditions that are more common among the elderly, such as diabetes. However, there are changes in the touch sensations among healthy older adults.

According to Molton and Terrill,[32] approximately 60%-75% of people over the age of 65 report at least some chronic pain, and this rate is even higher for those individuals living in nursing homes. Although the presence of pain increases with age, older adults are less sensitive to pain than younger adults.[33] Farrell[34] looked at research studies that included neuroimaging techniques involving older people who were healthy and those who experienced a painful disorder. Results indicated that there were age-related decreases in brain volume in those structures involved in pain. Especially noteworthy were changes in the prefrontal cortex, brainstem, and hippocampus. Women are more likely to identify feeling pain than men.[35] Women have fewer opioid receptors in the brain, and women also receive less relief from opiate drugs.[36] Because pain serves an important indicator that there is something wrong, a decreased sensitivity to pain in older adults is a concern because it can conceal illnesses or injuries requiring medical attention.

Chronic health problems, including arthritis, cancer, diabetes, joint pain, sciatica, and shingles are responsible for most of the pain felt by older adults.[37] Cancer is a special concern, especially “breakthrough pain” which is a severe pain that comes on quickly while a patient is already medicated with a long-acting painkiller. It can be very upsetting, and after one attack many people worry it will happen again. Some older individuals worry about developing an addiction to pain medication, but if medicine is taken exactly as prescribed, addiction should not be a concern.[38] Lastly, side effects from pain medicine including constipation, dry mouth, and drowsiness may occur that can adversely affect the elder’s life. Some older individuals put off going to the doctor because they think pain is just part of aging and nothing can help. Of course this is not true. Managing pain is crucial to ensure feelings of well-being for the older adult. When chronic pain is not managed, the individual will restrict their movements for fear of feeling pain or injuring themselves further. This lack of activity will result in more restriction, further decreased participation, and greater disability.[39] A decline in physical activity because of pain is also associated with weight gain and obesity in adults.[40] Additionally sleep and mood disorders, such as depression, can also occur.[41] Learning to cope effectively with pain is an important consideration in late adulthood, and working with one’s primary physician or a pain specialist is recommended.[42]


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  2. This chapter was adapted from select chapters in Lumen Learning's Lifespan Development, authored by Martha Lally and Suzanne Valentine-French available under a Creative Commons Attribution-NonCommercial-ShareAlike license, and Waymaker Lifespan Development, adapted from Laura Overstreet's Lifespan Psychology.
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Health in Late Adulthood: Primary Aging Copyright © 2022 by Diana Lang; Nick Cone; Laura Overstreet; Martha Lally; and Suzanne Valentine-French is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.