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3.1 Normal Aging and Its Manifestations

Aging is an inevitable process. During this time, all organs tend to lose work as they age. Therefore, aging is basically a decline in the regenerative and reparative potential of tissues and organs. Aging takes place on various levels and there are factors like epigenetics and hereditary changes responsible for it (Roberts and Allen 2016). Along with this, many cells lose their function because there is an increase in the levels of pigments and fatty substances in the cells. As aging continues the waste materials build up inside the cells, airways and the organs become less efficient. This altogether leads to an altered cell membrane permeability (Gemma et al. 2007).

Aging is a slow and gradual process and continues throughout our lives. All our organs lose function with time. For example, the pumping ability of the heart of a 20 year old is about 10 times more efficient than that of a person aged 30–40 years. Organs like heart, kidneys, and lungs undergo substantial amount of changes, and such changes occur slowly over time (Gladyshev 2016). Whenever an organ undergoes a lot of stress or work, it results in abnormalities like sudden heart failure. Certain factors like medications, sudden increase in physical activity or change in environment tends to increase the work load on the organs. Aging also makes it difficult for the body to remove the drugs from the body as the kidneys and liver function at a slower rate (López-Otín et al. 2013) (Fig. 3.1).

Fig. 3.1
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Main contributors of aging associated diseases

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3.1.1 The Aging Theory

Aging remains an enigma for the biologists (Gladyshev 2016). Various theories have been put forth to solve the mysteries associated with aging and its mechanisms. According to some theories, aging results due to the ultraviolet light exposure over time that causes injuries. Other studies have established that aging is controlled on the genetic level. There is no single process that can explain aging, as it is a complex phenomenon which varies and affects different people in entirely different patterns and diverse rates (Gemma et al. 2007).

3.1.2 Aging Cells and Their Replacement Mechanism

As cells age, they become less efficient in doing their normal duties. There has to be a mechanism where the old cells must die, as a normal feature of the cells. This process is called apoptosis where a sequence of reaction is initiated by the genes, that results in cell death. This is important because only in this way, the old cells will create room for the new ones (Saretzki and von Zglinicki 2002).

3.1.3 Telomeres and Aging

Telomeres are structures made from protein and DNA, present at the end of chromosomes which serve to protect the overall genome from degradation. Therefore, telomeres tend to preserve the genetic information. As part of normal cell division, a very small region of telomere is lost. Upon reaching a certain telomeric length, the cell senescence occurs and enters into the apoptotic phase. The telomere length therefore, determines the lifespan of a certain cell or organism. However, there are many external factors, i.e. lifestyle changes that may fasten this process and brings about early aging and health deterioration. The factors responsible for early aging and shortening of telomeres include obesity, exposure to pollution, unhealthy diet, and stress, etc. (Shammas 2011).

The evidence for the telomere aging hypothesis comes from the finding that the telomeres in the normal human cells (young individuals) shorten when they are grown in cell culture (Shay and Wright 2001). Some telomeric proteins like TRF1, TRF2, TIN2, TPP1, Rap1 are expressed almost all the time. Other proteins are expressed transiently, for example, the telomerase enzyme. Telomerase is a reverse transcriptase enzyme and it works by extending the 3′ end by adding TTAGGG repeats at chromosome ends. Therefore, it is important for a cell to have normal telomerase activity so that the integrity of chromosomes is maintained. In case of accelerated telomere shortening, manifestation of a number of age-associated diseases like diabetes, heart failure, osteoporosis, increased cancer risk takes place (Aubert and Lansdorp 2008).

According to studies, due to shorter telomere length, older people have three to eight times higher affinity to encounter infectious diseases or heart related disorders. In order to delay the signs of aging due to telomere shortening and to help protect telomeres, a number of antioxidants can be added to regular diet. These antioxidants are found in foods like salmon, tuna, sesame seeds, chia seeds, green tea, black raspberries, olive fruit, kiwi, red grapes, etc. (Shammas 2011).

3.1.4 The Role of Mitochondria in Aging

Mitochondria plays a significant role in the manifestation of age-related disorders, most importantly, the neurodegenerative diseases. Apart from energy production, mitochondria is involved in a number of functions, like calcium homeostasis, oxidative phosphorylation, and cell signaling to the nucleus in states of stress. It also participates in apoptosis and formation of cell’s free radicals. The fact that mitochondria plays an important role in overall aging process is because it has a reduced DNA repair capacity and has an estimated tenfold greater rate of mutation than nuclear DNA (Haas 2019).

According to a study by Peter McGuire, the major player in aging of a cell are the mitochondrial damage-associated molecular patterns (mtDAMPs), which when released activates a number of proinflammatory cytokines like TNF-a, IL-1, IL-6 (McGuire 2019). This in turn results in an enhanced inflammation, declining function of T cells and susceptibility to viral infections in the older individuals (Jang et al. 2018) (Fig. 3.2).

Fig. 3.2
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Aging leads toward different diseases by cell structures damage

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3.1.5 Aging Organs

The optimal working of the organ depends on how well the resident cells function. The cells that are old have altered function compared to the new cells. Also in some organs, the number of total cells decrease as aging proceeds, for example, in the testes, kidneys, and liver. There are certain conditions in the elderly where the progressive loss of nerve cells leads to neurodegenerative disorders like the Parkinson’s disease or the Alzheimer’s disease (Wang and Bennett 2012). The loss of function of one organ may affect the efficiency of other organ and contribute altogether towards aging. For example, atherosclerosis results when the blood vessels are narrowed due to the accumulation of cholesterol, as a result the organ will not function well because the blood flow has been decreased (Gemma et al. 2007).

In the aged individuals, majority of the functions stay normal but the reduction in overall function of organs is due to the fact that they are less able to handle different stresses. These include extreme temperatures, strenuous physical activity, disorders, effects of drugs, etc. (López-Otín et al. 2013).

3.1.6 Signs of Aging

As aging proceeds, different people show different sings. But some of the common are as follows:

3.1.6.1 Sensory Changes Associated with Aging

As age advances, the risk of certain chronic hearing and vision related disabilities also increases which results in a decline in overall health and well-being. In the UK, about 27% (one in four) of aged adults 61–80 years suffer hearing disability (Crimmins 2018). Among adults aged 65 years, 13% have a vision impairment. Therefore, hearing and vision impairment is very common in aged population around the world (Cavazzana et al. 2018). One interesting finding suggests a link of hearing and vision impairment with disability, frailty, cardiovascular disease (CVD). However, these impairments are said to be preventable to some extent. The conditions like CVD, frailty, and disability can therefore be avoided if the hearing and vision impairments are addressed in time (Liljas 2017).

3.1.6.2 Hearing Loss

Hearing loss advances with age and is said to affect over half (55%) of the adults aged 75 years or more. Such losses can be prevented by the use of hearing aids. Hearing loss, other than aging, also occurs due to continuous exposure to loud noise. The loss which is age associated is called presbycusis (Huang and Tang 2010). During this phase it is also very difficult for the people to make sense out of the words because they cannot identify the consonants that are high pitched (k, t, s, p, and ch).

3.1.6.3 Vision Related Deficits

A change in a person’s vision is usually the first sign of aging. As people age, the following vision related deficits takes place:

  • The focal point of the eye becomes hard, which makes focusing on near objects harder.

  • It becomes harder to see in the dim light as the focal point becomes denser.

  • The eyes generally encounter dryness as the number of cells required for lubrication of the eye, decrease in number. Tear production is also reduced.

  • The number of nerve cells also reduce in number, disabling the accuracy of perception.

  • The focal point of the eye becomes yellow, it changes the way a color is perceived in normal conditions (Fine et al. 2000).

Loss of Close Vision

The elderly population, in their late 1940s usually complain about a discomfort whenever they observe an object closer than 2 feet. This condition is called presbyopia, where the focal point of the eye hardens. Usually, in order to assist the eye to the center, the lens changes its shape. Because a stiffer focal point makes focusing on the near objects very difficult. At the later stages in life, almost everyone goes through presbyopia and needs amplifying glasses (Khan et al. 2017).

Color Perception Changes

As the focal point tends to become yellow with time, colors are observed quite differently. It also becomes harder to differentiate between different colors. Specially the blue color may seem more gray and the blue background is indistinguishable (López-Otín et al. 2013).

Age Aged Individuals Need for Brighter Light to View Things

Consequently, the pupil of eye reacts very slowly in response to light. A very slow reacting pupil in the elderly makes them unable to see when they first enter a very dark room or become blinded for few moments when they enter a very bright room. The pupil widens and also narrows bringing less amount of light inside. This increased sensitivity to the amount of light is because of cataracts or areas that have darkened in the lens. Older people often see many dark spots moving in their field of vision. These are called “floaters,” which are small regions of normal fluids that have become solid over time. They do not usually interfere with the vision but can cause blurry images. Not only is the function of eye affected, its physical appearance also changes considerably (Stuen and Faye 2003).

  • The sclera of the eye (white region) gradually turns brown or yellow. This happens due to continuous exposure to wind, dust, and UV light.

  • People with a darker complexion may experience random blotches in the white region of the eye.

  • Calcium and cholesterol accumulation may appear as a grayish white ring on eye surface called arcus senilis. However, vision is not affected by this.

  • As the muscles around the eyes droop, and tendons stretch the lower eyelid tend to hang away. This results in a condition called ectropion, which tends to interfere with lubricating the eyeball thus making eyes dry (Liljas 2017).

3.1.6.4 Disturbances in Vestibular Functions During Aging

About 30–35% of older population suffers from the vestibular dysfunction. One common type of vestibular disorder in the elderly is benign paroxysmal positional vertigo (BPPV). Not only this but the elderly aged 65 face vestibular dysfunction due to injurious falls annually. This results due to balance impairments, and the older people experience more imbalances due to aging of the nervous system (Balatsouras et al. 2018). Such changes also impair walking capabilities, the elderly tend to walk with more care and slower pace to avoid any falls. The dysfunction of the vestibular system also leads to an altered spatial navigation. Aging altogether brings about rapid changes in the somatosensory function of an individual which manifests itself as visual impairments, decreased strength, and cognitive decline. The older adults are more prone to a decline in cognition and vestibular dysfunction mediates this decline (Shaffer and Harrison 2007).

3.1.6.5 Decline in Muscle Strength as a Consequence of Aging

As the aging progresses, usually by the age of 30, the overall muscle strength decreases. Major reduction in muscle strength takes place due to physical inactivity and reduced levels of growth hormones and testosterone. Moreover, muscles are unable to contract more frequently because the fast contracting muscle fibers are lost over a period of time. A case where extreme muscle loss takes place is called sarcopenia, which happens due to inactivity for a longer period of time, aging may or may not play a role in this situation. The regular decline in muscle strength accounts for about 10–15% in an adult’s life and even this can be prevented with regular exercise and healthy lifestyle (Jaul and Barron 2017).

3.1.6.6 Immunosenescence (Age-Related Changes in the Immune System)

Immunity play a crucial role in age-related changes, which are mediated by a chronic inflammatory state that leads to aging of the immune cells. The immune cells like the B cell and T cells repertoire undergoes a decline in generation, activation and results in dysfunction. This results in an overall reduction in a body’s strength to fight with different infections (Gruver et al. 2007). For instance, the infections of influenza and herpes zoster are common in the elderly and its vaccine is also not very effective. This implies the reason of slow healing of the wounds in older adults because of a delayed immune response. The total number of macrophages, neutrophils is also reduced resulting in an altered phagocytic activity (Jaul and Barron 2017).

3.2 Aging Associated Diseases

What is the reason for experiencing an overall decline in mental and physical health as aging progresses? A unit hypothesis clarifying the pathophysiology of various degenerative abnormalities in various organs, including Alzheimer’s, Parkinson’s, and other neurodegenerative issues, rheumatoid arthritis, atherosclerosis, and other cardiovascular sicknesses, macular degeneration, and diabetes, has been proposed to clarify how the physiological procedure of aging may prompt different diseases. This idea called the “free radical theory,” at first proposed by Harman, gives the most conceivable underlying reason for aging (Harman 1992). The fundamental reason of this hypothesis is that aging and its related manifestations are the net result of free radical-instigated harm and the lack of ability to balance these progressions by anti-oxidative safeguards. The formation of reactive oxygen and nitrogen species (ROS furthermore, RNS) initiates the transcription elements that exacerbates inflammation. The constant expression of such elements over a prolonged period leads to targeting the cells and organs leading to aging related diseases. This oxidative pressure and consequent incessant aggravation is a major factor that leads to majority of the aging related illnesses (Sarkar and Fisher 2006). A summary of the aging associated diseases and their mechanisms is given in Table 3.1.

Table 3.1 Different age-associated diseases and their mechanisms
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3.2.1 Contributing Factors for Aging Related Diseases

3.2.1.1 Social and Environmental Conditions

Two important predictors for a prolonged life are wealth and marriage. On the other hand, social seclusion envisages mortality and other hostile consequences in adults. Around 5% of older adults in their 80’s are leading an isolated life devoid of basic health necessities, which makes them susceptible to different diseases (Waite 2018). Around 13% of women and 8% of men above 85 years are residing in nursing care or other healthcare locales. These rates are decreased in recent times probably as a result of a lesser amount of disability and enhanced care alternatives at home.

Around 17 million people worked as family caregivers and volunteers to older adults during 2011 in the USA. Caregiving is characteristically an extended obligation and the work hours may well vary in accordance with the requirements of the patient. Individuals suffering with dementia are in dire need of constant care and support. Therefore, the family caregivers must have proper training, counseling, and employment facilitation to help the elderly patients with daily chores (Jaul and Barron 2017).

3.2.1.2 Polypharmacy and Hospitalization

Polypharmacy is described as the simultaneous use of 5 or above prescriptions to a sole patient. Such high number of medications come with a high probability of hostile drug reaction or drug–drug interaction. It may escalate the danger of falls, disabilities, and other harmful consequences (Hajjar et al. 2007). The care providers should be careful while prescribing medicines and should make note of any side effects, time of action, and proper dosage for the individuals over the age of 85. Hospitalization is considered as a normal practice amongst persons over the age of 85 mostly due to functional failure of the aged. As long as extensive acute care is taken at the home, older individuals can be saved from hospitalization and its difficulties like: further worsening of the condition due to iatrogenic infection. In order to avoid re-hospitalization, a routine medical checkup is important to minimize any errors that may lead to recurring disease manifestation (Singh 2016).

3.3 Types of Diseases Associated with Aging

3.3.1 Metabolic Diseases

3.3.1.1 Cardiovascular Diseases

Cardiovascular disease accounts for one of the most prevalent diseases in the older age. It affects the blood vessels and heart and is the leading cause of myocardial infarction (MI), coronary heart disease (CHD), and stroke. This disease is highly preventable if proper lifestyle measures are adopted, therefore reducing premature death ratio. In old age, a plethora of different conditions cause many diseases, similarly there has been a recent association of cardiovascular diseases with sensory impairments. A common mechanism of inflammation is implicated in both these conditions (Liljas 2017).

During the CVD, stiffness of the heart and blood vessels take place. This stiffness does not allow the arteries to carry more blood when pumped through the heart as a result causing increased blood pressure. This leads to an overall thickening of the heart muscle called hypertrophy (Jaul and Barron 2017). This makes it difficult for the heart to pump the blood, making physical activities more difficult as compared to that of a young heart. In CVD, the thickening of the capillary walls also takes place. This reduces the rate at which nutrients exchange takes place. The total volume of the blood also decreases, because there is a general reduction in total body water content as a person ages. In conditions of stress or illness, the pace at which red blood cell production takes place is lowered. Certain conditions that make the heart work harder include emotional stress, physical exertion, infections, and certain medicines (North and Sinclair 2012).

An overall change in the heart structure, with aging, leads to the formation of abnormal rhythms (arrhythmias) and are detected through ECG. Another common abnormality is the accumulation of lipofuscin—an aging pigment which is more common in the elderly. Because of stiffness of the heart valves, a certain disturbance in the heart sound is also observed called as the heart murmur. Apart from this, there are receptors in the blood vessels, called baroreceptors, these receptors help to normalize blood pressure. These receptors also undergo aging, which explains the reason of orthostatic hypotension in older people, a condition in which a person’s blood pressure falls abruptly when a person goes from a lying position to standing or sitting (Strait and Lakatta 2012).

Common Problems Associated with Cardio Vascular Diseases (CVD)

  • Hardening of the arteries (Arteriosclerosis)—fatty deposits in the blood vessels lead to this condition.

  • Angina (a type of chest pain caused due to reduced flow of blood to the heart muscle).

  • Arrhythmias (abnormal heart rhythm).

  • Anemia—usually occurs due to nutritional deficits or chronic infections.

  • High blood pressure/orthostatic hypotension.

  • Deep vein thrombosis, blood clots, peripheral vascular disease, varicose veins are all manifestations of the CVD.

  • In the older people, congestive heart failure is also very common.

  • Aortic stenosis or the aortic valve is the most common valve disease in the elderly.

  • Aneurysms may also develop in one of the major arteries from the heart or in the brain. They are caused by abnormal widening of the artery. If such an aneurysm bursts, it may lead to death.

3.3.1.2 Cerebrovascular Disease (Strokes)

Aging tend to bring about changes in the vascular endothelium and the arterial wall. According to recent studies, there is a reduction in vasodilatory capacity of the vascular endothelium. The arterial wall also undergoes changes due to calcium deposits and most importantly hypertrophy occurs that leads to an increase in vascular stiffness (Izzo et al. 2018).

Stroke is basically a vascular disease that directly affects brain and gives rise to a lot of manifestations. It is characterized by interrupted blood flow to the brain tissues due to breaking or closing of a cerebral artery. In the older adults, the prevalence is about 20–35%. In the western world, each year 10–12% deaths are caused due to stroke. Not only this, but it is also a leading cause of dementia and disability. Cerebral stroke tends to be a welfare issue, as the individuals are dependent upon others for their basic necessities (Gladyshev 2016). The protective function of the blood–brain barrier acts as a filter for the bloodstream in brain. As a person ages, the function of the BBB is distorted, the ability to selectively uptake nutrients is diminished. This in combination with inflammation like conditions leads to the formation of multi-infarct dementia (MID) and other neurodegenerative disorders (Farrall and Wardlaw 2009).

In the elderly population, the occasion of hemorrhagic events is more due a number of vascular structural changes like aneurisms, hypertension, increased cerebral trauma, amyloid deposits. It is quite evident from various studies that vascular dementia occurs in the older adults upon their exposure to a stroke or any hemorrhagic episode. In this type of dementia, the intellectual potential of a person is affected. The patients who are about 60, they are at a higher risk of experiencing a stroke associated vascular dementia, but here certain secondary conditions also exacerbate the disease, such as hypertension, diabetes, dyslipidaemias, etc. (Jaul and Barron 2017).

3.3.1.3 Hypertension

Another most common disease in the older adults is the hypertension which itself is the root cause of many other major diseases like atherosclerosis and CVD. However, its effects can be managed by bringing about positive changes in lifestyle and eating habits. Sedentary lifestyle and stress remains one of the prime causes for the diseases to persist and become severe (Logan 2011).

3.3.1.4 Bone and Joint Diseases

As aging proceeds bones become less dense, such moderate loss of bone density is called osteopenia and excessive loss of bone density is termed as osteoporosis. This excessive loss of bone density makes the bones become fragile and are susceptible to break even during a small accident. As estrogen (a female hormone) helps to main the bone density in women, upon menopause, less amount of estrogen results in further weakening of the bones (López-Otín et al. 2013).

Two other major factors that lead to the weakening of bones include reduction of calcium levels (as the body does not absorb maximum levels of calcium from dietary intake). Secondly, lower levels of Vitamin D further aggravate the disease. Some bones are more susceptible to weakening as compared to others. Most commonly affected bones include the spine bone, femur (thighbone), and radius and ulna (arm bones at wrist). As aging progresses, there are several changes taking place at the spine bone, which ends up in causing the head to slide forward which makes the throat compressed. This causes hard swallowing of food, and might as well result in occasional choking. The major reason that the older people become short is that their vertebra becomes dense and the tissues lose the lubricant fluid, making it thin and the spine becomes shorter (Jaul and Barron 2017).

Over the passage of time the joints become susceptible to injury because of many years of wear and tear. Such damage to the cartilage and use of joints leads to a condition called osteoarthritis which is the swelling and pain of joints. The joints of knee, hips, spine, and hands are usually affected. The elasticity of the ligaments which helps to bind the joints together is also lost with time and the tendons which binds muscle to bone also become less elastic. This as a result causes stiffness of joints and tissues weaken in the process contributing towards decrease flexibility and movements are altered while carrying on everyday tasks (Crimmins 2018).

3.3.1.5 Diabetes Mellitus

As people are becoming more and more overweight with increasing age, the diabetes rates are also increasing. The occurrence of diabetes amongst American adult population is likely to escalate more than 4 times by 2050. Cardiovascular diseases at the age of 85 are still influenced highly by Diabetes. Diabetes is also related directly to peripheral arterial disease and peripheral neuropathy, major contributing factor for diabetic foot ulcers and amputations. Every year around 6% and 0.5% of diabetic patients suffer from diabetic foot ulcers and amputations, respectively. Personalized management approaches are highly demanded in case of diabetes (Meneilly and Tessier 2001). Sulfonylureas and insulin transmit a considerable danger of hypoglycemia, therefore, the amount taken ought to be considered cautiously in susceptible older adults. Dosing needs may vary for patients treated with hypoglycemic agents, especially during post-acute care or when patients are sent from hospital to home in uncertain periods. Frequent foot inspections are crucial for individuals with diabetes to avoid amputations. Blood circulation in the legs likely improves with regular walking (Jaul and Barron 2017).

3.3.1.6 Cancer

Cancer tends to be the second chief reason of death in elderly. Though, by the age of 85, the death ratio of cancer starts to decrease. Still, slow growing tumors appear to occur frequently for this age group. People respond to cancer treatment in accordance to their overall health status rather than their age. People in their 1980s or 1990s must not be deprived of intensive cancer treatment just because of their physical weaknesses (Robinson and Turner 2003).

Screening is not endorsed for breast cancer beyond 75 years, because of inadequate evidence for a possible outcome, although this might be useful for women with higher life expectancy. Likewise, for people above the age of 75 years, colon cancer screening is suggested merely in circumstances when there is an extensive life expectancy and a seemingly resilient ability to bear cancer diagnosis. Life expectancy is relatively flexible in elderlies at any age, established on the basis of comorbidities and other elements. Numerous false positives like identification of slow growing tumors forbid the screening for prostate cancer (López-Otín et al. 2013).

3.3.1.7 Chronic Obstructive Pulmonary Disease

Evidence suggests that aging and illnesses due to prolonged inflammation are closely related. Chronic Obstructive Pulmonary Disease (COPD) is a very slowly developing disease due to prolonged inflammation of the lungs, thus, most of the patients are aged. Aging characteristically is the consistent decay of homeostasis which happens once the reproductive phase of life is concluded, which leads to aggregated risk of disease. Non programmed aging, i.e. failure of organs to heal DNA destruction due to oxidative stress or programmed aging, i.e. shortening of telomere due to repeated cell division may cause the disease (López-Otín et al. 2013). Pulmonary function gradually declines with aging due to increased pulmonary inflammation, along with physical changes, inferred as senile emphysema. Ecological fumes, for instance, smoke of cigarette or various pollutants, may well hasten the aging of lungs by the formation of molecules such as histone deacetylases and sirtuins which subsequently prompts accelerated development of COPD (Gan et al. 2004).

3.3.1.8 Age-Related Macular Degradation

This disease affects the vision of the older adults. In this disease macula is affected, which is the part of retina where all nerve cells exist in close connection and therefore this is the region where the eye focusses the images that we observe. Therefore, this area is responsible for developing a clear and sharp focused image with fine details. The macula is affected as we age and it affects people over 65 years of age causing blindness or vision loss (Jaul and Barron 2017).

3.3.1.9 Blood Production

Aging declines the amount of active bone marrow cells, where new blood cells are formed. So, the blood cells production reduces. However, the bone marrow typically produces sufficient blood cells all the way till death. Issues may surface at a time where there is an increased requirement for blood cells, for example, during anemia, infection and/or severe bleeding happens. Under such conditions, when large amount of blood cells are needed at old age, bone marrow might show limited capacity to meet the higher blood cells demand (López-Otín et al. 2013).

3.3.1.10 The Immune System

The action of cells of the immune system retards with aging. Immune cells have a capacity to recognize and then remove foreign substances, for instance, bacteria, viruses, or cancer cells. Due to the reduction in the number of immune cells, certain manifestations occur in the aging adults as following (Gruver et al. 2007).

  • Cancer is found commonly amongst older people.

  • Older people are more frequently effected by some infections, for instance: influenza and pneumonia resulting more often in death. Moreover, vaccines seem to be less protective for older people though influenza, pneumonia, and shingles vaccines may provide some level of protection (Khan et al. 2017).

  • Allergic symptoms are not very severe. Eventually, due to the poor performance of the immune system, autoimmune disorders are less likely to occur.

3.3.2 Psychological and Cognitive Diseases

3.3.2.1 Frailty Syndrome

Frailty is a very common clinical syndrome associated with increasing age and leads to health conditions like: falls, hospitalization, incident disability, and mortality. In theory, frailty is a clinically detectable state of amplified vulnerability caused by aging related decay in reserve and function across multiple physiologic systems so that the capacity to handle daily or acute stressors is compromised (Xue 2011). According to Fried et al. frailty is a condition where the body of an adult meet three out of five phenotypic conditions representing compromised energetics: (Fried et al. 2001)

  • Low grip strength.

  • Low energy.

  • Slowed waking speed.

  • Low physical activity.

  • Unintentional weight loss.

Modern efforts on frailty have enhanced the level of understanding on the aging process and its possible biological connection. The operational definition of frailty, its domains either cognitive or physical and its correlation with aging, disabilities, and prolonged sicknesses indicate that additional effort is required for improved understanding of frailty. Nonetheless, researchers and clinicians agree upon the strong effect of frailty on elder individuals, their caretakers and overall society. Though precise cures for frailty are still to be explored, the pre-existing medical methods offer convenient ways to identify prone people, which may lead to better treatment by keeping in view specific vulnerabilities and susceptibility for adverse health consequences (Xue 2011).

Regular exercising in order to strengthen the muscles can somehow delay loss of muscle mass and strength which contributes to frailty. On the contrary, being physically inactive, especially extensive bed rest during a disease, can significantly contribute to the muscle loss (Gladyshev 2016).

3.3.2.2 Cognitive Aging

By the age of 85, things like: difficulty in finding words, short-term memory loss, and slower processing of information are noticed quite often. Such regression in cognitive abilities can upset driving capabilities and may as well cause financial exploitation. Such manifestations can also lessen ability to cognize complex medical information. There is no uniform rate at which brain ages and typical cognitive aging may not lead to dementia. There are few functions like altruism, empathy, knowledge, and wisdom which generally increase with normal aging, giving the elderly a chance at society (Langa 2018).

3.3.2.3 Dementia

Chances of dementia rise with increasing age. Over the years, death toll from Alzheimer’s disease have escalated than that for cardiovascular disease. The occurrence of dementia is estimated to increase to 131 million by 2050 over the globe. Even though dementia screening seems to possess inadequate clinical benefit as treatments are just marginally effective, however, provides alternates for improvement of public health. Several adults continue to live with dementia and might possibly be living precariously (Jaul and Barron 2017). The Folstein Mini-Mental State Examination though is frequently used tool to analyze dementia but it comprises numerous limitations. Individuals with dementia require chances for thinking incentive, caretaker’s sustenance and perhaps evolved equipment to keep them safe (Waite 2018).

3.3.2.4 Dementia Including Alzheimer’s Disease

In the USA, Alzheimer’s disease is presently ranked to be the sixth foremost reason of death, however, recent assessments show that the disease may hike up to the third, after heart disease and cancer.

Dementia is most commonly caused by Alzheimer’s in the elderly. Dementia is the loss of behavioral capabilities and cognitive activities like thinking, remembering, and reasoning so much so that it obstructs an individual’s day-to-day life’s activities. Severity of dementia may increase when it is mildly affecting a person’s functioning, to the most severe stage, where the person essentially depends on someone else even for the very basic chores of everyday life (Karantzoulis et al. 2011).

Numerous studies are being conducted to understand excessively about various biological traits of Alzheimer’s. Progresses in brain imaging allows scientists to comprehend the growth and extent of atypical amyloid and tau proteins in the living brain, along with alterations in brain structure and functioning. Researchers are also determining the very primitive stages in the development of sickness by understanding deviations in the brain and body fluids which can be used to diagnose Alzheimer’s symptoms before they actually surface (Langa 2018).

The question that why Alzheimer’s occur in the elderly is yet to be answered. Researchers are trying to find relevant reasons as to how the changes occur with age inside the brain like: inflammatory actions, reduction of specific parts of the brain, mitochondrial malfunctioning, creation of unstable free radicals and vascular damage that may cause harm to the neurons and affect other brain cells leading to Alzheimer’s disease (Karantzoulis et al. 2011).

3.3.2.5 Parkinson’s Disease

Age is one of the most important players for the manifestation of Parkinson’s disease (PD). The exact source of PD is yet unidentified, still the researchers rely on the fact that it results due to the amalgamation of some genetic and other external factors which are yet to be specified. PD disturbs numerous regions of brain and body. The death of neurons in brain region called the substantia nigra pars compacta and consequently reduced levels of dopamine are mostly accountable for motor symptoms like: shivering, stiffness, and loss of impulsive movement (Nussbaum and Ellis 2003). Investigations have revealed that the substantia nigra pars compacta displays high damage of neurons than other areas of the brain. Furthermore, with aging, organelles’ become nonproductive leading to the accumulation of waste products that cannot be recycled and hence destroy the neurons (Reeve et al. 2014).

It is assessed that individuals with PD lose around 80% or even more of the dopaminergic neurons establish the motor symptoms. Consequently, over the time, the altered functioning of mitochondria and other organelles lead to the buildup of abnormal forms of alpha-synuclein which can possibly cause loss of neurons leading to motor symptoms (Jaul and Barron 2017).

3.3.2.6 Depression

Depression is not a standard outcome of aging. Sorrow may be some usual reaction to life activities that befall with aging like: grief, pensiveness, damage to cognition, social and/or physical attributes that lead to sickness. Major depression is common all the way through maturity but their occurrence rates decline between the age of 60 and 80, rising again after that. Occurrence of depression above the age of 85 is twice the rate between 70 and 74. Depression is more likely in the elderly who are confined to in old houses and the individuals with disabilities (Alexopoulos 2005). Various approaches are implied for the diagnosis and treatment in order to reduce the amount of suffering, improve overall attitude of an individual, and lower the chances of suicide. Suicide rates amongst 85-year-old white Americans are extremely common.

3.4 Conclusion

The process of aging is universal but not the same in all the individuals. Various manifestation of aging, for example, decline in vision and auditory patterns, slow processing of information, lack of coordination can be addressed in a better way if proper awareness is created among the elderly. This would not only help the patients but also prepare the caretakers to manage all sorts of unforeseen problems.

Social and mental stressors are also a major cause of early aging. Timely addressal of these issues may prevent isolation, cognitive decline, and depression leading to suicide. Regular exercising should be a part of routine to strengthen the muscles and prevent disabilities during later life. Maintaining a balanced body weight by taking care of the diet may increase the total well-being of an individual as the incidence of diseases like osteoarthritis, diabetes, and CVD become less likely. People should be facilitated in such a way that in coming times, individuals over the age of 85 profit from home-based facilities and technologies along with innovative conveyance and housing facilities prospects for social contribution, plus plans to support family caregivers.