The Aging Population

Life expectancy is generally increasing worldwide, resulting in more people entering what is traditionally described as old age. This means that the elderly populations, in the United States and many other countries, are getting older. In the United States, this is referred to as “the graying of America.”

The statistics confirm that the population in the United States is aging. The number of people in the U.S., who are 65 or older, has been slowly and steadily increasing, and this older population has grown by over 20% in the last decade and is an increase that is expected to continue. With each passing year, more and more of the population will be elderly. There are many reasons why this is happening and will continue to happen. Better access to improved healthcare is partially responsible. Many diseases and illnesses that could not be treated or that could greatly decrease the life span can now be cured.

Lifestyle changes have contributed to this trend as well. The number of people who smoke has decreased significantly, and fitness and nutrition have become a more popular lifestyle trend. Add to these changes the fact that the birth rate of the Baby Boomer generation has been high, and that Baby Boomers now make up a large part of the population. Many of these people will be turning 65 years old during the next decade.

Defining “Old” and Elderly People

The words old, old age, elderly, and older adults are frequently used but they do not have universally accepted definitions. Gerontologists (professionals who study aging) have developed categories such as the young-old (60-69 years) and the middle-old (70-79 years) and others to describe the elderly but these categories have not definitively defined what is old or old age.

There are no universally accepted definitions for a person who is old or belonging to an old age category. Old age or being elderly tends to be defined in context. In a society where many people die in infancy or before reaching age 35, someone who is 50 may be considered old. The context can also depend on the individual referring to a person who is “old.” If a teenager were asked if a 67-year-old woman is old, the answer would likely be “yes,” however, a 67-year-old person may possibly disagree.

The aging process has four dimensions: 1) biological, 2) chronological, 3) psychological, and 4) social. When defining “old,” it is important to delineate which dimension, or combination of dimensions, is being used. Some people may consider a person who is 66 to be old, and that is true in the chronological sense since that person is older than most of the population. Other people may not consider this person old if the 66-year-old person is in perfect health, exercises every day, is happy and well-adjusted, and has an active professional and social life. It is questionable whether a 66-year-old person who is psychologically and socially youthful is an “old” person.

Although the aging process is usually associated with being old, the biological process of aging actually begins early in life, as discussed in more detail later on. Aging is experienced differently for each person: the aging process can happen slowly or quickly. Each aspect of aging, the biological, chronological, psychological, and social also develops at its own rate.

The Aging Process

The aging process is defined as the gradual, decreased ability of the body to function and to heal itself. People think of aging as equivalent to being old but aging actually begins in the late teens. That is the time when a person’s physical capabilities are at their maximum. As a person moves past the late teen years, the body begins to decline. The person gradually loses strength, eyesight, and hearing becomes weaker. All of the organ systems slowly become less able to function. The heart and lungs are not as strong, the immune system is less able to fight infections, and other parts of the body do not function as well as they previously did.

Further, the aging process occurs over time. The aging process, the gradual decline in a person’s health and physical abilities, is very slow. For most of a person’s life, the aging process is not noticeable and does not interfere with daily life.

Stress and Repair

Each minute of every day, a person’s body must deal with internal and external stress but, fortunately, it is usually able to handle the stress to fight off infections and repair damage. As a person gets older, the body loses the capability for self-healing with two results: 1) damage that cannot be repaired and 2) susceptibility to disease. The body wears out, it cannot do what it once did, and acute and chronic illnesses may occur.


Throughout most of life, the aging process is slow and gradual. However, at a certain point, it begins to speed up. When that happens, several things occur: 1) the effects of aging begin to be noticeable to the individual, 2) the effects of aging can be measured by a physical examination or testing, 3) the older person becomes more susceptible to disease, 4) the older person is less able to recover from illness, and 5) the older person develops an acute or chronic disease.

The Weak Link

Eventually the balance of stress and repair is tipped in favor of damage and an acute or chronic disease happens. An older person may develop heart failure, chronic kidney disease, or suffer an acute illness, such as a stroke or infection, where recovery is difficult. Therefore, one or more of the organ systems will be the “weak link” that leads to illness.

Aging begins early and it progresses slowly. It represents a gradual decline in the functional ability of the body and a decrease in the ability of the body to handle stress. All of this makes a person vulnerable to illness and infection and, eventually, vulnerable to acute or chronic diseases.

The Causes of Aging

The question of why a person ages is a source of constant investigation and there are many theories. Scientists have speculated that aging represents an imbalance between stress and repair. There is also evidence that aging itself seems to cause an increase in internal stress that is separate from the normal external stress, tissue, and organ damage that all human bodies undergo.

Another theory of aging is that the process of homeostasis is disrupted as a person gets older. Homeostasis is defined as the ability of the body to maintain an internal environment that allows for optimal functioning. For example, the brain, the heart, and muscles all work best within a certain range of body temperature and if the body temperature becomes too high or too low, heat can be produced or lost as needed. Homeostatic mechanisms may simply stop working after a certain point.

It could also be that a person’s DNA is programmed to age. These bodily changes mean that waste products from metabolism are eliminated less effectively during old age. As waste products accumulate, a person shows signs of aging. Also, if a person’s DNA contributes to aging, this would explain, in part, why everyone ages differently. Some people live to be quite old and they have few health problems and minor decreases in functional ability. Longevity and freedom from illness are another part of the aging process but it is not clear why some people live longer and healthier lives. Regardless of the process, aging happens to everyone.

Since the aging process affects each person differently, descriptions of what happens to a person’s body during aging can only be described in general terms. When and how aging affects a person’s health on the individual.

Bone Composition and Skin Changes

A person gains weight in older age. The percentage of body weight that is fat is increased and the person gradually loses muscle mass. The loss of muscle mass begins slowly but increases more quickly as an individual age. The number of fast-twitch muscle fibers, the ones that give us power, decreases so strength is gradually lost. Joints become less flexible because the tendons and ligaments deteriorate, and the bones lose calcium and become thinner and more brittle. The bones and joints, in particular, are constantly in a balance between breakdown and rebuilding, and as people get older, this balance is irreversibly more inclined towards breakdown. The skin gets thinner and dryer as people age and it gets noticeably more fragile. Receptors for touch and pain in the skin do not function as well. In addition, thinning of the skin plus loss of the fat layer immediately below the skin means that body heat is more easily lost.

Cardiovascular System and Aging


The cardiovascular system is comprised of the blood vessels, the blood, and the heart. The purpose of the cardiovascular system is to deliver oxygen and nutrients to the organs and tissues and to help eliminate metabolic waste products. These functions are done by the heart pumping the blood throughout the body by way of the arteries, capillaries, and veins.

Several important age-related changes occur in the cardiovascular system. The heart muscle becomes thicker and stiffer and much less compliant, as do the arteries and the other blood vessels. In most people, the heart muscle does not become weaker with age but it does lose some capacity for response to stress. In addition, the process of atherosclerosis, typically known as hardening of the arteries, increases with age and the majority of elderly people have atherosclerostic plaques in the arteries of the brain, the heart, and major blood vessels. Blood volume is unaffected by age, but the ability of the bone marrow to produce more blood cells during times of stress is definitely decreased. Finally, the blood must be able to form clots to prevent bleeding, but in many older persons, blood clotting is suboptimal.

Gastrointestinal Tract and Aging


The gastrointestinal (GI) tract breaks down food, absorbs nutrients and fluids, and eliminates wastes. Each part of the GI tract, from the mouth to the lower GI tract, can be affected by the aging process.

In the mouth, the gums recede as people get older and the teeth become more prone to decay. The esophagus, the muscular tube that connects the oral cavity to the stomach, is less sensitive to pain and the gastroesophageal (GE) valve, which is technically a sphincter that separates the esophagus from the stomach, begins to leak. This allows acidic stomach contents to splash back into the esophagus, but because pain sensation in the esophagus is diminished, the acid reflux may go unnoticed.

Other parts of the GI tract experience age-related changes as well. The stomach becomes more sensitive to the irritating effect of certain drugs, such as aspirin and ibuprofen, the small intestine of an older adult does not absorb calcium as efficiently as the small intestine of someone younger, the lower bowel loses muscle tone and is less able to expel feces, and the strength and tone of the anal sphincter are decreased.

Genito-Urinary System and Aging


The urinary bladder of an elderly person has a smaller maximum capacity. The bladder is not emptied completely during urination and the ability to voluntarily delay urination is decreased. The female urethra becomes shorter and may not close completely after every act of urination.

Sexual function for men and women is adversely affected by age and, obviously, the ability to reproduce is compromised. For men, the prostate gland gradually becomes enlarged with age.

Immune System


The immune system defends against disease and infection. Individuals are constantly exposed to bacteria, viruses, and other harmful pathogens but the immune system recognizes and neutralizes them. The immune system ages along with the rest of the body, and as people get old, the immune system becomes less strong and less effective. This is one of the primary reasons that older people are more susceptible to autoimmune diseases, cancers, and infections. A diminished immune system also limits the ability to recover from illnesses.

Sensory Changes


Changes in sensory ability are some of the most noticeable effects of aging. Many older adults will report that they cannot hear or see as well as they once could. They also note that their senses of taste and smell are diminished.


The eyes experience significant changes from aging. The ability to distinguish between colors decreases, the eyes cannot adapt to low light conditions or darkness, and presbyopia, which is commonly called nearsightedness, develops. Presbyopia limits the ability of the eyes to focus on objects that are close at hand. Someone who has presbyopia must use corrective lenses or will have to hold a book or an object at arm’s length in order to see it clearly.


Hearing is seriously affected by age. Two examples of this are changes in pitch discrimination and sound location. Older people have difficulty in hearing high-pitched sounds, especially high-pitched consonants such as t or k. Words that contain those letters may not be well understood or heard clearly. A person’s ability to distinguish speech from background noise diminishes in old age. This factor may be more responsible for hearing impairment than the volume of another person’s speech, or decreased hearing acuity by the hearer. Interference by surrounding noise may be primarily responsible for an elderly person’s ability to understand what another person is saying.

Ambulation Difficulty

Older people often have muscle and joint pain, stiffness, and weakness. Balance and vision disorders and peripheral neuropathy also become more prevalent with advancing age. All of these problems combine to make ambulating difficult for older adults.

Fall Risk

Falls are relatively frequent in older adults. Approximately one out of three adults, 65 years or older, has a fall, or several falls, each year. Falls are the leading cause of non-serious and serious injury in this age group, and lacerations, hip fractures, and traumatic brain injury after a fall are not uncommon. Another consequence of falls is the fear of falling. After one or two falls many older adults begin to become less active and they are hesitant to ambulate. While this may in one sense limit the risk of falling, it can also increase the risk of falling as muscles and joints that are not exercised become weak and stiff.



Food intake decreases as people age and there are multiple reasons why this happens. The appetite declines and poor dentition makes chewing and eating difficult. The sense of taste and the sense of smell that are so important to the enjoyment of food are not as acute as they once were, and social isolation and depression tend to make people less likely to eat. The end result can be malnutrition and increased susceptibility to disease.


Many older adults are taking multiple medications, otherwise known as polypharmacy. When polypharmacy exists, there is an increased risk for drug interactions and medication errors.

In some cases, medical insurance pays for some of the cost of a person’s needed medications, but the cost of co-payments may cause an older adult to skip doses or to stop taking a medication for a while in order to save money. Not taking medication appropriately or as prescribed can lead to health complications in an older person.


The aging process is a profound and life-changing experience. The body slowly begins to weaken, resistance to disease is decreased, and recovery time is prolonged.

Acute and chronic medical conditions become more common and life-disrupting conditions, such as incontinence and fall, can severely affect independence and quality of life.

Many people age 65 or older self-report some sort of disability. These may be minor or they may be significant, requiring the older person to need skilled assistance. The aging process is individual, however, age-related changes are inevitable.

People think of aging as equivalent to being old but aging begins in the late teens. That is the time when a person’s physical capabilities are at their maximum.

Aging doesn’t necessarily mean that a person is old and will have inevitable age-related acute or chronic health issues, but aging does involve changes to the body that could lead to a disease state or physical disability based on the individual’s life patterns and physical condition.

Exercise may be tolerated in an older individual and specifically referenced current research focused on the ability of elderly people to succeed in tests of endurance.

Because 95% of our patients are elders, we must take extra time with them to keep everyone safe. Time, patience, and the ability to listen make us all better at what we do!!

The Aging Population Quiz

    * Required Information

    1. The aging process is defined as the gradual, decreased ability of the body to function and to heal itself.*


    2. The gastrointestinal (GI) tract breaks down food, absorbs nutrients and fluids, and eliminates wastes.*


    3. As we age, joints become less flexible because the tendons and ligaments deteriorate, and the bones lose calcium and become thinner and more brittle.*


    4. The immune system ages along with the rest of the body and as people get old the immune system becomes stronger and more effective.*


    5. Food intake increases as people age.*