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Ageing: the story on HearLore | HearLore
Ageing
Jeanne Calment died in 1997 at the age of 122 years, holding the title of the oldest reliably recorded human in history, yet her life was not merely a statistical anomaly but a window into the biological limits of human existence. While the global average life expectancy hovers around 80 years in 33 countries, Calment's longevity challenged the prevailing assumptions of the 20th century, suggesting that the maximum human lifespan might be closer to 115 years, though some theories once proposed 125. Her story is inextricably linked to the broader mystery of why most organisms age and die, while others, like the genus Hydra, possess regenerative abilities that allow them to avoid dying of old age entirely. The accumulation of changes in a human being over time encompasses physical, psychological, and social shifts, yet Calment's life demonstrated that the human body can sustain function far beyond what was previously thought possible. The death of roughly 150,000 people each day across the globe, with about two-thirds dying from age-related causes, underscores the universality of the ageing process, making her exception a profound scientific puzzle rather than a common occurrence.
The Biological Clock of Damage
The biological basis of ageing is often attributed to the accumulation of damage, such as DNA oxidation, which causes biological systems to fail over time, yet this damage is not uniform across all species or even all cells within a single organism. 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, revealing that the factors influencing biological ageing fall into two main categories: programmed and error-related. Programmed factors follow a biological timetable that might be a continuation of inherent mechanisms that regulate childhood growth and development, while factors causing errors or damage include internal and environmental events that induce cumulative deterioration in one or more organs. For instance, dogs annually lose approximately 3.3% of the DNA in their heart muscle cells while humans lose approximately 0.6% of their heart muscle DNA each year, numbers that closely mirror the ratio of the maximum longevities of the two species, which are 120 years versus 20 years. This genetic instability suggests that genetic damage, particularly gene loss, is almost certainly the central cause of ageing, as stated by lead author Bernard L. Strehler, and it is this accumulation of errors that drives the degenerative processes collectively responsible for the decline we observe in older adults.
The Midlife Acceleration Shift
Common questions
Who is the oldest reliably recorded human in history and when did they die?
Jeanne Calment is the oldest reliably recorded human in history and she died in 1997 at the age of 122 years. Her life serves as a window into the biological limits of human existence rather than being merely a statistical anomaly.
What is the biological basis of ageing and how does it affect DNA in heart muscle cells?
The biological basis of ageing is often attributed to the accumulation of damage such as DNA oxidation which causes biological systems to fail over time. Dogs lose approximately 3.3% of the DNA in their heart muscle cells annually while humans lose approximately 0.6% of their heart muscle DNA each year.
When does the rate of human ageing accelerate according to a 2025 study published in Cell?
A 2025 study published in Cell reveals a noticeable shift in the rate of ageing around age 50 with the steepest changes occurring between ages 45 and 55. The research indicates that human ageing accelerates midlife rather than following a linear trajectory throughout adulthood.
What is the Hayflick limit and when was it discovered by Leonard Hayflick?
The Hayflick limit is the biological constraint where normal human cells die after about 50 cell divisions in laboratory culture. Leonard Hayflick discovered this limit in 1961 and it contrasts sharply with the potential immortality of single-celled organisms.
How much did ageism cost the United States in one year according to a Yale School of Public Health study?
Ageism cost the United States $63 billion in one year according to a Yale School of Public Health study. The United Nations Population Fund estimates that by 2050 the number of people aged 60 and older will rise to approximately 22%.
What are the names of the ageing suits used to simulate the effects of getting older?
The ageing suits used to simulate the effects of getting older include the GERT suit, the R70i exoskeleton, and the AGNES suit. These devices create feelings of ageing by adding extra weight and increased pressure to points like the wrists and ankles while impairing vision and hearing.
A 2025 study published in Cell examined protein changes in 516 tissue samples collected from 76 human donors ranging in age from 14 to 68, revealing a noticeable shift in the rate of ageing around age 50, with the steepest changes occurring between ages 45 and 55, particularly in blood vessels. Among the various tissues studied, the aorta showed the most significant changes in protein makeup, and one of the proteins identified, GAS6, was linked to faster ageing; when introduced into mice, it triggered early vascular deterioration and other signs of systemic ageing. The research also found that some organs, like the adrenal gland, begin showing ageing-related changes as early as age 30, suggesting that not all parts of the body age at the same pace. This finding challenges the traditional view that human ageing progresses steadily throughout adulthood, instead indicating that human ageing accelerates midlife rather than following a linear trajectory. Understanding this shift could help guide earlier and more targeted approaches to support healthier ageing, potentially allowing for interventions before the steepest decline sets in, which is critical given that the incidence of osteoarthritis rises to 53% in the 60, 64 age cohort and almost half of people older than 75 have hearing loss.
The Immortality of the Microscopic
Even within humans and other mortal species, there are cells with the potential for immortality, such as cancer cells which have lost the ability to die when maintained in a cell culture such as the HeLa cell line, and specific stem cells such as germ cells producing ova and spermatozoa. In artificial cloning, adult cells can be rejuvenated to embryonic status and then used to grow a new tissue or animal without ageing, yet normal human cells however die after about 50 cell divisions in laboratory culture, a limit known as the Hayflick limit, discovered by Leonard Hayflick in 1961. This biological constraint contrasts sharply with the potential immortality of single-celled organisms, which have been thought to not age and to be potentially immortal under favorable conditions, although 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 evolution of eukaryotic sexual reproduction, which occurred with the emergence of the fungal/animal kingdoms approximately a billion years ago, marked the point where ageing and mortality of the individual organism became more evident, allowing the sexual organism to pass on some of its genetic material to produce new individuals and could itself become disposable with respect to the survival of its species.
The Social Cost of Ageing
Ageism cost the United States $63 billion in one year according to a Yale School of Public Health study, highlighting the economic and social toll of how society treats older persons, yet the United Nations Population Fund (UNFPA) estimates that by 2050, the number of people aged 60 and older will rise to approximately 22%, up from the current 11%. Population ageing has three possible causes: migration, longer life expectancy, and decreased birth rate, and it poses significant social and economic challenges to the work which can be overcome with the right set of policies to equip individuals, families and societies to address these challenges and to reap its benefits. In the United States, the Bureau of Labor Statistics estimates that one in four American workers will be 55 or older by 2020, and older people generally incur more health-related costs than do younger people in the workplace and can also cost more in worker's compensation and pension liabilities. The global economic crisis has increased financial pressure to ensure economic security and access to health care in old age, and to elevate this pressure, social protection floors must be implemented in order to guarantee income security and access to essential health and social services for all older persons and provide a safety net that contributes to the postponement of disability and prevention of impoverishment in old age.
The Paradox of Aging and Health
As people age, subjective health remains relatively stable, even though objective health worsens, and in fact, perceived health improves with age when objective health is controlled in the equation, a phenomenon known as the paradox of ageing. This may be a result of social comparison; for instance, the older people get, the more they may consider themselves in better health than their same-aged peers, and elderly people often associate their functional and physical decline with the normal ageing process. Positive self-perceptions of ageing are associated with better mental and physical health and well-being, and positive self-perception of health has been correlated with higher well-being and reduced mortality among the elderly, though this relationship is generally stronger for men than women and may only be true in some circumstances. The increase in demand for cosmeceuticals has led scientists to find ingredients for these products in unorthodox places, such as the secretion of cryptomphalus aspersa, or brown garden snail, which has been found to have antioxidant properties, increase skin cell proliferation, and increase extracellular proteins such as collagen and fibronectin, yet the pursuit of longevity and the postponement of senescence remains a contentious issue in bioethics, with some arguing that human life is not worth living after age 75, while others contend that longevity should be pursued in association with the attainment of quality of life.
The Design of Empathy
One way to help younger people experience what it feels like to be older is through an ageing suit, such as the GERT, the R70i exoskeleton, and the AGNES suits, which 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, and also impair vision and hearing to simulate the loss of these senses. To create the loss of feeling in hands that the elderly experience, special gloves are a part of the uniforms, and use of these suits may help to increase the amount of empathy felt for the elderly and could be considered particularly useful for those who are either learning about ageing, or those who work with the elderly, such as nurses or care centre staff. Design is another field that could benefit from the empathy these suits may cause, as when designers understand what it feels like to have the impairments of old age, they can better design buildings, packaging, or even tools to help with the simple day-to-day tasks that are more difficult with less dexterity, and designing with the elderly in mind may help to reduce the negative feelings that are associated with the loss of abilities that the elderly face. This approach to empathy and design is crucial in a world where the number of people aged 60 and older is projected to rise to 22% by 2050, and where the annual growth in national health spending is driven not mainly by increasing demand from ageing populations, but rather by rising incomes, costly new medical technology, a shortage of health care workers and informational asymmetries between providers and patients.