Older People - Patterns of Illness, Physiological Changes and Multiple Pathology

Original Editor - Bhanu Ramaswamy as part of the AGILE Project.

Top Contributors - Kim Jackson, Tolulope Adeniji, Evan Thomas, Lucinda hampton and Vidya Acharya

Good Practice

Distinguishing the accumulation of age related disease (morbidity) from true ageing is difficult. An important aspect of management of older adults is to recognise and understand how body systems are interlinked. Awareness of pathological and normal age-related physiological changes will assist your assessments and help you decide on best management of older people.

Don't approach this section with a feeling of impending doom. Also remember that not everyone experiences all mentioned issues, and those with disabling conditions have often accommodated to the changes without too much of an impact on their lifestyle.

In earlier life, the signs and symptoms of illness might be explained by a single diagnosis. In older people, the number of active or inactive pathological processes might compromise both the precise diagnosis as a basis of treatment, and include or be impacted on by a further disability. Hence awareness of different pathological processes and of normal age-related physiological changes will assist your assessment and management of older people.

Discussion Point

‘True ageing should be universal and observed in all older members of a species. It should be intrinsic, that is, attributable to basic mechanisms innate to the organism and not exclusively due to modifiable environmental effects. It should be progressive in that it is seen as a gradual process of accumulated damage and decline.’ (Gershon and Gershon, 2000) This decade-old statement still holds true.

As we live longer, degenerative problems are becoming pre-eminent in older age and much of health care practice falls within the category of ‘longer-term / chronic' conditions. In many of these conditions, by the time they manifest themselves a successful cure is elusive. Distinguishing the accumulation of age related disease (morbidity) from true ageing is difficult. Izaks and Westendorp[1] theorise a relationship between age and disease, placing them on either side of a continuum and finding little to distinguish between them.

Certain commonly seen conditions are liable to be disregarded by the individual, relatives or by the doctor as they develop slowly. For example, gradual onset of alterations in voice, in facial appearance, cold sensitivity, lethargy and slowing may be easily attributable to the ageing process that myxoedema (decreased activity of the thyroid gland) can be overlooked. Postural changes, stiffness and restricted activity often considered a part of ageing may cause the rigidity and bradykinesia of Parkinson’s to be missed. Investigations are often provoked due to comments from a visitor, especially one who has not seen the person for a long time and to whom the changes are noticeable. It is useful to identify underlying mechanisms that lead to true age related changes, as opposed to age related disease.

Physiological Changes Peculiar to Older Adults

Cardiovascular System

Cardiovascular system also known as circulatory or vascular system involve the circulation of blood, oxygen and nutrients throughout the body.[2] Ageing impact both structural and functional components of cardiovascular system. Structurally, the following are the characteristics of older adult cardiovascular system, which include increase in the thickness of the left ventricular (LV);increased arterial stiffness; the cardiac conduction system;degenerative changes of the conduction system and the endothelial dysfunction[3] . Functionally, older adult circulatory system can be characterised by altered coupling of LV and arterial stiffness and function, and attenuated baroreflex and autonomic reflexes.[3][4]. This changes impact on the older cardiovascular system functional maximal level like an adults.

Pulmonary System

There are several changes in the pulmonary system among older adults. Among these changes are decrease in the thoracic volume capacity and decrease lung volume[5]. Increased mucociliary dysfunction, decreased cough strength and decrease muscle performance results in poor airway clearance among the older adults[5]

Musculoskeletal system

Musculoskeletal system supports the body system to enable individual to be mobile and functionally independent. It has three components, which are muscular strength, endurance and flexibility[6]. Ageing results in loss of muscle mass and strength and this further impacts on the older adults functional performance required for functional independent [7]. Sarcopenia and Osteoporosis are another changes and it contributes to bone fragility and fracture risk.

Neuromuscular System

Hunter et al.,[8] affirmed that age related physiological changes in older adults affect the motor unit and neural input that further impact on the motor function. Consequently, this affect the older adults functional independent and contribute to sarcopenia disease[8][9].

Vestibular system

The vestibular system entails vestibular nerve, brainstem and cerebellar processing circuits and this system in germane in postural balance, self motion, spatial orientation and so on[10]. Aging physiological changes in the vestibular system may have an impact on the balance and result in a fall[10]. Also, this phtsiological change in the vestibular system of older adults may explain dizziness and imbalance, benign positional paroxysmal vertigo among older adults[11].

Memory Changes

Memory contributes to quality of life and instrumental activities of daily living cannot be achieved without an optimal memory function. Age-related physiological changes in healthy ageing vary with manifestations of these changes in brain structure, function, or behavioral patterns[12]. The major structural changes in memory with ageing are the brain shrinking in volume and the ventricular system expanding;the brain volume reduce; and reduction in cognitive capacity like decline in executive function an episodic memory[13].

Altered Responses to Illness

Illnesses often present differently in old age than in youth. Regulation of body temperature is unstable or less responsive, so pyrexia may not be as marked as would be expected even in severe infections such as pneumonia, appendicitis or pyelonephritis. The converse, a lack of awareness of cold, or of the capacity to react normally to it, may lead to hypothermia.


Delirium is characterised by an acute, fluctuating change in mental status with inattention and altered levels of consciousness. Categories include hyperactive delirium, characterised by agitation and visual hallucinations, as opposed to hypo-active delirium characterized by lethargy and withdrawal. Precipitating factors including immobility, malnutrition, inter-current illness, dehydration and, stress of admission to hospital or other unfamiliar settings[14].


Pain is common in older people. However as people age, they complain less of pain. The reason may be a decrease in the body's sensitivity to pain or a more stoical attitude toward pain. Some older people mistakenly think that pain is an unavoidable part of ageing and thus minimize it or do not report it. Even in conditions that cause intense pain in earlier life (e.g. angina or fractures), there may be so little discomfort, or pain is referred in such a bizarre way, that diagnosis is delayed – sometimes with fatal consequences. Pain is often not correctly recognized and treated in people with dementia, and use of a scale such as the Abbey pain scale may help to recognize when a person is in pain.

Response to Drugs

Poly-pharmacy is a common phenomenon among the older adults and this is because ageing is a risk factor for many chronic conditions. As a result, physiological changes in older adults and polypharmacy contribute to adverse drug reactions seen in older adults.[15]. It has been claimed that the adverse drug reaction in older adults is due to increased pharmacodynamic sensitivity and a prescription error.[16] Therefore, when prescribing drugs to older adults, their physiological responses to these drugs need to be considered.

Recovery from Illness

Due to physiological changes seen in older adults as a result of aging, recovery becomes slowed once they become ill. In a previous study, Boyd and associates[17], claimed that older adults rarely recover to their baseline in  functional activities of daily living after acute medical illness. Also, Keary and colleagues [18], noted that there seems to be association between heart rate recovery and performance. Thus, aging effects on both the cardiovascular system and cognitive performance may explain some of the reasons why older adults may be slowed to recover from illness.

See also Perceptions about Ageing and Ageism 


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