Ageing
[11][12] However, evidence has been reported that aging leading to death occurs in the single-cell bacterium Escherichia coli, an organism that reproduces by morphologically symmetrical division.
The sexual organism could henceforth pass on some of its genetic material to produce new individuals and could itself become disposable with respect to the survival of its species.
[17] This classic biological idea has however been perturbed recently by the discovery that the bacterium E. coli may split into distinguishable daughter cells, which opens the theoretical possibility of "age classes" among bacteria.
[19] In artificial cloning, adult cells can be rejuvenated to embryonic status and then used to grow a new tissue or animal without ageing.
Intelligence declines with age, though the rate varies depending on the type and may, in fact, remain steady throughout most of the human lifespan, dropping suddenly only as people near the end of their lives.
Individual variations in the rate of cognitive decline may therefore be explained in terms of people having different lengths of life.
A cataract occurs when the lens of the eye becomes cloudy, making vision blurry; it eventually causes blindness if untreated.
[1] Older adults are more prone to social isolation as well, which can further increase the risk for physical and mental conditions such as anxiety, depression, and cognitive decline.
[62][63][64] In the 21st century, researchers are only beginning to investigate the biological basis of ageing even in relatively simple and short-lived organisms, such as yeast.
A model organism for the study of ageing is the nematode C. elegans – having a short lifespan of 2–3 weeks – enabling genetic manipulations or suppression of gene activity with RNA interference, and other factors.
[68] Programmed factors follow a biological timetable that might be a continuation of inherent mechanisms that regulate childhood growth and development.
[68] Factors causing errors or damage include internal and environmental events that induce cumulative deterioration in one or more organs.
[105][106] The major contributors to mortality risk reduction appear to be a higher consumption of vegetables, fish, fruits, nuts and monounsaturated fatty acids, such as by consuming olive oil.
[111] A meta-analysis found that resistance training with elastic bands or kettlebells provided significant improvements to grip strength, gait speed, and skeletal muscle mass in patients with sarcopenia.
[111] Furthermore, another analysis found that the positive effects of resistance exercise on strength, muscle mass, and motor coordination reduce the risk of falls in the elderly, which is a key factor for living a longer and healthier life.
[111] [112] General recommendations for improvements to gait speed, strength, and muscle size for reduced fall risk are resistance training programs with two to three 40-60 minute workouts per week, consisting of 1-2 sets of 5-8 repetitions of 2-3 different exercises for each major muscle group, but individual considerations must be taken due to differences in health status, motivation, and accessibility to exercise facilities.
[117] UNFPA said that this "requires, among others, working towards the development of international human rights instruments and their translation into national laws and regulations and affirmative measures that challenge age discrimination and recognise older people as autonomous subjects".
Young people tend to have fewer legal privileges (if they are below the age of majority), they are more likely to push for political and social change, to develop and adopt new technologies, and to need education.
[117] Ageing has occurred due to development which has enabled better nutrition, sanitation, health care, education and economic well-being.
[117] It has been argued that population ageing has undermined economic development[124] and can lead to lower inflation because elderly individuals care especially strongly about the value of their pensions and savings.
Evidence suggests that pensions, while making a difference to the well-being of older persons, also benefit entire families especially in times of crisis when there may be a shortage or loss of employment within households.
"[117] Due to increasing share of the elderly in the population, health care expenditures will continue to grow relative to the economy in coming decades.
[131] Faria claims that postponement of senescence as well as happiness and wisdom can be attained in old age in a large proportion of those who lead healthy lifestyles and remain intellectually active.
UNFPA states that:[121] "A life-cycle approach to health care – one that starts early, continues through the reproductive years and lasts into old age – is essential for the physical and emotional well-being of older persons, and, indeed, all people.
The large number of suggestions in the literature for specific interventions to cope with the expected increase in demand for long-term care in ageing societies can be organized under four headings: improve system performance; redesign service delivery; support informal caregivers; and shift demographic parameters.
In addition, certain reforms to the Medicare system in the United States decreased elderly spending on home health care by 12.5% per year between 1996 and 2000.
[139] In China, respect for elderly is often the basis for how a community is organized and has been at the foundation of Chinese culture and morality for thousands of years.
[150][151][152] These suits create the feelings of the effects of ageing by adding extra weight and increased pressure in certain points like the wrists, ankles and other joints.
[157] In their 1987 article, Rowe and Kahn characterized successful aging as involving three components: a) freedom from disease and disability, b) high cognitive and physical functioning, and c) social and productive engagement.
The Book of Job (c. 6th century BC) describes the human lifespan as inherently limited and makes a comparison with the innate immortality that a felled tree may have when undergoing vegetative regeneration:A man's days are numbered.
