The word “longevity” can also be translated as “life expectancy”. Statistically, longevity always refers to the average number of years a person lives in modern times. In other words, the “typical lifespan” of a person. This looks a little different for men than for women, also according to statistics. But there are other factors that influence a person’s life expectancy. More on this in the following.
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Life expectancy – what is it based on?
- Australia: 81,72 years
- Germany: 79,41 years
- France: 81,09 years
- Great Britain: 81,73 years
- Italy: 80,33 years
- Japan: 82,84 years
- Monaco: 79,73 years
- Spain: 81,07 years
- USA: 78,24 years
These are all the average life expectancies of people living in the countries mentioned. Of course, there have also been deviations in the last centuries and up to the present day. Particularly impressive are the people who became much older than one would have expected. We do not want to deprive you of these celebrities.
The Gerontology Research Group validates the current longevity records according to modern standards and maintains a corresponding list. Record holders from the last centuries to the present day include:
- Eilif Philipsen (1682-1785, 102 years, 333 days): the first person to reach the age of 102 (on 21 July 1782) and whose age could be confirmed.
- Geert Adriaans Boomgaard (1788-1899, 110 years, 135 days): the first person to reach the age of 110 (on 21 September 1898) and whose age could be confirmed.
- Margaret Ann Neve (18 May 1792 – 4 April 1903, 110 years, 346 days): the first female to live to this age and be validated.
- Jeanne Calment (1875-1997, 122 years, 164 days): the oldest person in history whose age has been confirmed by modern documents.
- Sarah Knauss (1880-1999, 119 years, 97 days): the second oldest documented person in modern times and the oldest American woman.
- Jiroemon Kimura (1897-2013, 116 years, 54 days): the oldest male person in history whose age has been confirmed by modern documents.
The most important factors of longevity
Scientists who deal with the topic of longevity always include possible methods for extending life expectancy in their considerations. Evidence-based studies show that longevity depends on two main factors: Genetics and lifestyle.
Genetics
Twin studies estimate that about 20-30% of the variation in human life expectancy is due to genetics, the rest to individual behaviour and modifiable environmental factors. Although, according to a US-Belgian-British research database, over 200 human gene variants are associated with longevity, these explain only a small part of the heritability.
Lymphoblastoid cell lines prepared from blood samples of centenarians show a significantly higher activity of the DNA repair protein PARP (Poly ADP Ribose Polymerase) than cell lines from younger (20 to 70 years old) individuals. The lymphocytic cells of centenarians also show characteristics typical of cells of young people, both in terms of their ability to initiate the repair mechanism after sublethal oxidative H2O2 DNA damage and in terms of their PARP gene expression. These results suggest that increased PARP gene expression contributes to longevity in centenarians, which is consistent with the DNA damage theory of ageing.
In July 2020, scientists used public biological data from 1.75 million people with known life expectancy to identify ten genomic loci that appear to have a significant impact on healthspan, lifespan and longevity. Their study suggests that high iron concentrations in the blood probably reduce healthy human life expectancy and genes involved in iron metabolism probably increase it.
Lifestyle
Longevity can be changed through one’s own lifestyle. Physical activity, dietary habits, living conditions and pharmaceutical as well as nutritional interventions form an important core. A 2012 study found that even modest amounts of leisure time and physical activity can extend life expectancy by up to 4.5 years.
Diet
Increasing research on unicellular and invertebrate model organisms, rodents, monkeys and humans suggests that nutrition plays a much broader and more important role in influencing the mechanisms of ageing and associated diseases than previously thought. Now, at the latest, you should perhaps reconsider your previous eating habits.
Biological pathways
Four well-studied biological pathways known to regulate ageing and whose modulation has been shown to influence longevity are insulin/IGF-1, the mechanistic target of rapamycin (mTOR), AMP-activating protein kinase (AMPK) and the sirtuin pathway.
Autophagy
Autophagy plays a central role in prolonging health and lifespan. This is understood to be the independent cell cleansing. The body is capable of this process during periods of fasting. The cells are then able to break down and utilise their own components. These can also be degenerated cells, for example, which destroy themselves in the course of autophagy and subsequently no longer pose a danger to the body. The process of autophagy is a crucial one in the whole longevity discussion. In this context, the topic of (intermittent) fasting is currently “en vogue” again.
Changes over time
In pre-industrial times, deaths in young and middle age were more frequent than today. This is not due to genetic causes, but to environmental factors such as diseases, accidents and malnutrition.
Nevertheless, there are many examples of people from before the 20th century who achieved a life expectancy of 85 years or more. Among them are John Adams, Cato the Elder, Thomas Hobbes, Eric of Pomerania, Christopher Polhem and Michelangelo. This also applied to poorer people such as peasants or workers. Genealogists will almost certainly find ancestors who lived to be 70, 80 and even 90 years old even several hundred years ago.
The 1871 UK census, for example, gave an average male life expectancy of 44 years, but if infant mortality is subtracted, men lived to an average of 75 years. Current life expectancy in the UK is 77 years for men and 81 years for women, while the average life expectancy in the United States is 74 years for men and 80 years for women. Therefore, the difference between the past and the present is not as great as perhaps previously assumed.
Studies have shown that Black American men have the shortest life expectancy of any population group in the US, averaging 69 years. This reflects the overall poorer health and higher prevalence of heart disease, obesity, diabetes and cancer among Black American men.
Women generally live longer than men. Theories for this include a smaller body and therefore less strain on the heart, a stronger immune system (as testosterone acts as an immunosuppressant) and a lower tendency to engage in physically dangerous activities.
It is debatable whether the pursuit of longevity is a worthwhile health care goal. Bioethicist Ezekiel Emanuel, who was also one of the architects of ObamaCare, has argued that longevity beyond 75 should not be seen as necessarily positive. However, this is contradicted by neurosurgeon Miguel Faria, who states that life at a healthy age can absolutely be worth living and that longevity should always be pursued in conjunction with quality of life. Faria has discussed how longevity combined with a healthy lifestyle can lead to a postponement of ageing and happiness and wisdom in old age. And that should be everyone’s goal in the end.
The natural limit of life expectancy
Most biological organisms have a naturally limited life expectancy. Only a few are considered immortal.
Given that different animal and plant species have different potential for longevity, the defect accumulation theory of ageing attempts to explain why an organism’s potential for longevity sometimes correlates positively with its structural complexity. It states that while biological complexity increases individual lifespan, it has an opposite effect in nature, as the survivability of the entire species can be compromised if it leads to a prolonged developmental process, which is an evolutionarily vulnerable state.
According to the hypothesis of antagonistic pleiotropy, one of the reasons why biological immortality is so rare is that certain categories of gene expression that are beneficial in youth may become detrimental in older age.
Misinformation and myths in the context of longevity
Longevity myths are traditions about long-lived people. As a rule, these myths are used to spread practices aimed at increasing longevity. However, in most cases there is no scientifically proven evidence for these theories and claims. One example is the water from Bimini, which is said to heal old age. Or the Okinawa diet, which is associated with an exceptionally high life expectancy. None of the same could ever be scientifically proven.
The future of longevity
The United Nations has made projections that extend to the year 2300. If these forecasts are to be believed, life expectancy in most industrialised countries will be between 100 and 106 years and will continue to rise, albeit at a slower rate than before. These projections also indicate that life expectancy in poor countries in 2300 will still be lower than in rich countries, in some cases by up to 20 years.
The UN itself has pointed out that the differences in life expectancy may not exist so far in the future, especially since the exchange of technology between rich and poor countries and the industrialisation and development of poor countries could lead to their life expectancy fully converging with that of rich countries long before that time. The UN warns that these projections are uncertain and also points out that any change or advance in medical technology could invalidate them.
The recent increase in rates of lifestyle diseases such as obesity, diabetes, hypertension and heart disease, on the other hand, could even slow down or reverse this trend of increasing life expectancy in industrialised countries, but this is not yet the case.
Jennifer Couzin-Frankel looked at how much mortality would have to fall due to various causes in order to increase life expectancy and concluded that most of the increases in life expectancy to date are due to improved survival rates among young people. She believes it is unlikely that the average longevity at birth will ever exceed 85 years. Michio Kaku argues that genetic engineering, nanotechnology and future breakthroughs will accelerate life expectancy indefinitely. Genetic engineering has already led to a doubling of the life expectancy of certain primates and to the fact that human skin cells can divide in the laboratory and live indefinitely without developing cancer.
Reliable data from 1840 to 2002 show that life expectancy has increased linearly for men and women, albeit more slowly for men. For women, the increase was almost three months per year, for men almost 2.7 months per year.
As can be concluded, people’s longevity seems to have increased on average in recent decades. Nonetheless, there were people several centuries ago who became just as old as we are today. Our lifespan is primarily related to our genetics and lifestyle. The good thing is that we can intervene in both independently and thereby prolong our lives. In times when diseases of civilisation such as cancer or diabetes are on the increase, it is necessary to take health into one’s own hands and finally take responsibility for one’s own longevity.
