**Aging Process**

**Chapter 1**

Provisional chapter

**Ageing Process and Physiological Changes**

Ageing is a natural process. Everyone must undergo this phase of life at his or her own time and pace. In the broader sense, ageing reflects all the changes taking place over the course of life. These changes start from birth—one grows, develops and attains maturity. To the young, ageing is exciting. Middle age is the time when people notice the age-related changes like greying of hair, wrinkled skin and a fair amount of physical decline. Even the healthiest, aesthetically fit cannot escape these changes. Slow and steady physical impairment and functional disability are noticed resulting in increased dependency in the period of old age. According to World Health Organization, ageing is a course of biological reality which starts at conception and ends with death. It has its own dynamics, much beyond human control. However, this process of ageing is also subject to the constructions by which each society makes sense of old age. In most of the developed countries, the age of 60 is considered equivalent to retirement age and it is said to be the beginning of old age. In this chapter, you understand the details of ageing processes and associated phys-

DOI: 10.5772/intechopen.76249

Keywords: ageing, physiological changes, elderly health, sensory changes, geriatrics

The term 'Elderly' is applied to those individuals belonging to age 60 years and above, who represent the fastest growing segment of populations throughout the world. The percentage of elderly in developing countries tends to be small, although numbers are often large. In the year 1990, there were more than 280 million people belonging to the age 60 years or over in developing regions of the world, and 58% of the world's elderly were living in less-developed

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

Ageing Process and Physiological Changes

Shilpa Amarya, Kalyani Singh and

Shilpa Amarya, Kalyani Singh and

http://dx.doi.org/10.5772/intechopen.76249

Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

Manisha Sabharwal

Manisha Sabharwal

Abstract

iological changes.

1. Introduction

regions [1].

#### **Ageing Process and Physiological Changes** Ageing Process and Physiological Changes

DOI: 10.5772/intechopen.76249

Shilpa Amarya, Kalyani Singh and Manisha Sabharwal Shilpa Amarya, Kalyani Singh and Manisha Sabharwal

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.76249

#### Abstract

Ageing is a natural process. Everyone must undergo this phase of life at his or her own time and pace. In the broader sense, ageing reflects all the changes taking place over the course of life. These changes start from birth—one grows, develops and attains maturity. To the young, ageing is exciting. Middle age is the time when people notice the age-related changes like greying of hair, wrinkled skin and a fair amount of physical decline. Even the healthiest, aesthetically fit cannot escape these changes. Slow and steady physical impairment and functional disability are noticed resulting in increased dependency in the period of old age. According to World Health Organization, ageing is a course of biological reality which starts at conception and ends with death. It has its own dynamics, much beyond human control. However, this process of ageing is also subject to the constructions by which each society makes sense of old age. In most of the developed countries, the age of 60 is considered equivalent to retirement age and it is said to be the beginning of old age. In this chapter, you understand the details of ageing processes and associated physiological changes.

Keywords: ageing, physiological changes, elderly health, sensory changes, geriatrics

## 1. Introduction

The term 'Elderly' is applied to those individuals belonging to age 60 years and above, who represent the fastest growing segment of populations throughout the world. The percentage of elderly in developing countries tends to be small, although numbers are often large. In the year 1990, there were more than 280 million people belonging to the age 60 years or over in developing regions of the world, and 58% of the world's elderly were living in less-developed regions [1].

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

According to World Population Prospects (1950–2050), the proportion of elderly in developing countries is rising more rapidly, in comparison with developed ones [2]. The report published by the US Department of Health and Human Services shows that more developed nations have had decades to adjust to this change in age structure (Figures 1 and 2). As we see in Figure 1, it has taken more than a century for France's population aged 65 or older to rise from 7 to 14%, whereas many developing countries are growing rapidly in number and percentage of older individuals [2].

It is expected that by the year 2020, 70% of the world's elderly population will be in developing countries, with the absolute number exceeding 470 million which is double the number of the developed world [5]. The main factor responsible for this changing pattern of population ageing includes a rapid decline in both fertility and premature mortality [6]. Decline in fertility is particularly apparent in some developing countries like China, Cuba and Uruguay, although the fertility level in other developing countries such as Kenya, Zaire and Bangladesh remains

Ageing Process and Physiological Changes http://dx.doi.org/10.5772/intechopen.76249 5

Ageing is associated with many neurological disorders, as the capacity of the brain to transmit signals and communicate reduces. Loss of brain function is the biggest fear among elderly which includes loss of the very persona from dementia (usually Alzheimer's disease). Multiple other neurodegenerative conditions like Parkinson's disease or the sudden devastation of a

Alzheimer's and Parkinson's diseases are the progressive neurodegenerative diseases associated with ageing [9]. Alzheimer's is characterised by progressive cognitive deterioration along with a change in behaviour and a decline in activities of daily living. Alzheimer's is the most common type of pre-senile and senile dementia. This disease causes nerve cell death and tissue loss throughout the brain, affecting nearly all its functions. The cortex in the brain shrivels up and this damages the areas involved in thinking, planning and remembering. The shrinkage in a nerve cell is especially severe in the hippocampus (an area of the cortex that plays a key role in the formation of new memories) as well as the ventricles (fluid-filled spaces within the brain) also grow larger. Alzheimer's disease causes an overall misbalance among the elderly by causing memory loss, changes in personality and behaviour-like depression, apathy, social

withdrawal, mood swings, distrust in others, irritability and aggressiveness [10, 11].

Nearly, 33 million Indians have neurological disorders, and these occur twice as often in rural areas [12]. According to the World Health Organisation (WHO) [13], nearly 5% of men and 6% of women aged 60 years or above are affected with Alzheimer's-type dementia worldwide. In India, the total prevalence of dementia per 1000 elderly is 33.6%, of which vascular dementia constitutes approximately 39% and Alzheimer's disease constitutes approximately 54% [14]. Stroke is another common cause of mortality worldwide [13]. However, in India, the prevalence rate of stroke among elderly is reported to be very low compared to Western countries

A mild decline in the overall accuracy is observed with the beginning of the 60s that progresses slowly, but sustained attention is good in healthy older adults. Cognitive function declines and

2. Ageing process and physiological changes

stroke are also increasingly common with age [8].

2.1. Changes in nervous system

high [7].

[15–17].

2.2. Cognition

Figure 1. Speed of population ageing in developed countries. Source: U.S. Census Bureau [3]; Kinsella & Gist [4].

Figure 2. Speed of population ageing in developing countries. Source: U.S. Census Bureau [3]; Kinsella & Gist [4].

It is expected that by the year 2020, 70% of the world's elderly population will be in developing countries, with the absolute number exceeding 470 million which is double the number of the developed world [5]. The main factor responsible for this changing pattern of population ageing includes a rapid decline in both fertility and premature mortality [6]. Decline in fertility is particularly apparent in some developing countries like China, Cuba and Uruguay, although the fertility level in other developing countries such as Kenya, Zaire and Bangladesh remains high [7].
