The novel Lifespinners makes a distinction between longevity and radical life extension, with the older residents of Wellowfern finding themselves on the cusp between the two. Longevity is incremental and refers to an unusually long life, while radical life extension is more exponential and involves big leaps in lifespan enabled by unprecedented technological and biomedical advances.
Longevity and the Blue Zones
The world’s human population is ageing, although very unevenly. Global life expectancy at birth is 73.2 years (females 75.6, males 70.8). This compares with just under 50 years in the mid-1950s. The countries with highest life expectancy are Japan (85.03), Switzerland (84.25), Singapore (84.07), Italy (84.01) and Spain (83.99) (Worldometer, UN estimates). Lowest life expectancy is in Chad (52.52).
The oldest known living person is a Spanish-American woman aged 116 and the oldest man a Venezuelan aged 113. The current record lifespan was set by a French woman who died in 1997 aged 122, while a Japanese man lived to 116, dying in 2013. The life expectancy gap between the sexes is narrowing. It stems from a combination of genetics and lifestyle factors (e.g. smoking). Progressive loss of the Y chromosome in older men is linked to cardiovascular disease, with greater Y loss increasing the risk of death.
The well-known Blue Zones are five places where human lifespan is notably longer than average. They are: Okinawa, Japan; Sardinia, Italy; Nicoya, Costa Rica; Icaria, Greece; and Loma Linda, California. Each area has its own food, types of exercise and community structure, but they have common elements. Their way of life includes a nutritious diet rich in natural food and low in meat, daily movement through walking and physical work, a strong and enduring sense of purpose, and supportive relationships within the family and local community. While genes can often increase the risk for certain diseases, the Blue Zones highlight the importance of external environmental influences and social connections in how our DNA controls our bodily systems.
Changes in lifestyle and behaviour can ward off illness, avert premature death and increase lifespan. In modern societies, this often requires a willingness to make healthier choices related to diet, smoking and drinking, exercise, rest and sleep, type of work, stress management, social connections and health awareness. Thoughtful housing design and sensitive local planning can also promote more social contact, activity and mutual support, resulting in a holistic solution that provides an environment conducive to boosting lifespan.
Personality and mindset
Researchers are exploring the links between personality, longevity and the body’s immune system. There is a growing body of evidence to indicate that an optimistic mindset and the personality trait of conscientiousness correlate with a long and healthy life. Greater optimism is associated with less inflammation, healthier lipid levels and higher antioxidants, as well as a better diet and more effective management of stressful situations.
Scientists have discovered a group of ‘super-agers’, whose memories are on a par with younger adults and whose brains have greater hippocampus volume and a visual cortex displaying youthful patterns. There are links between the body’s circadian rhythms and how individuals age. Circadian rhythms are the physical, mental and behavioural changes that follow a 24-hour cycle. They are regulated by our natural timing devices known as biological clocks, which are made up of specific molecules and located around the body. Calorie restriction and timing of eating (earlier in the day and over a shorter time period) are both beneficial. Some treatments for ageing diseases are also more effective if given at specific times of day.
Genetic effects and ageing cells
Medical advances, immunisation and improved daily diets, hygiene and social conditions allow people in more prosperous societies to have longer lives. They also enable us to live to an age where we may experience the effects of negative mutations in our genome. Some genetic mutations can have a positive effect in youth but a negative effect as we age.
Cellular senescence is important to understanding cognitive decline in older age. The affected cells are still alive but have stopped dividing and are harmful to organ function. In the brain, they can block neuroregeneration and there is growing evidence that clearing out senescent cells with senolytic drugs may reverse some cognitive defects. For understandable reasons, people who are concerned for their health tend to prioritise physical fitness, while giving little or no attention to cellular level wellness and the need to control inflammation. Continuous low-grade inflammation is concealed until it produces symptoms indicating a heart condition, cancer or a neurodegenerative disease. A practical plan for slowing the inflammation process includes eating a variety of plant foods and nuts, playing a musical instrument, practising short bursts of high-intensity exercise and turning the shower cold for an icy rinse.
The role of the lymphatic system is also gaining more recognition as research extends our understanding of how this crucial network of nodes, vessels and fluids carries nutrients and relays chemical messages. The lymph nodes in the neck, armpit, stomach and groin act as filters, trapping or destroying toxins and attacking viruses, bacteria and cancer cells. This relies on muscle action and if it is slowed by inactivity or poor nutrition, it can result in inflammation, fatigue and joint pain. Impairment of the lymphatic vessels in the brain is linked to higher levels of amyloid-beta deposits present in Alzheimer’s disease. Suggested pro-lymph activities include: saunas and hot baths; herbs and spices; massage, humming and yoga; running, cycling or bouncing on a trampoline.
As the older population has increased in many countries, so have frailty and illness among the oldest group. The average 80-year-old has four age-related conditions and current research has a strong focus on extending healthspan, enabling people to stay healthy for longer and potentially until the end of life.
A big challenge is to understand progressive changes in function and design interventions that delay the onset of age-related diseases. Dementia, cancer, stroke, cardiovascular disease and diabetes are now among the leading health-related killers in older age. These diseases, as well as limiting conditions such as arthritis and osteoporosis, share common features or hallmarks of ageing.
The ageing process is also influenced by the shortening of telomeres, which are protective sections of DNA capping the ends of our chromosomes. Each time a cell divides, a part of the repeating sequence in a telomere is lost. When the telomeres become too short to work effectively, a cell will die or stop dividing.
Drugs that are already in use to treat specific health conditions are being tested in research on the ageing process. These include medicines that zone in on the hallmarks of ageing, such as deteriorating stem cell function and dysfunctional mitochondria within cells. Tackling the biological causes of ageing may stop diseases taking hold and help older people to avoid living with several health conditions at the same time (multimorbidity).
Biological age and reversal
Scientists are using the body’s internal clocks, as well as computer algorithms, to measure biological age and assess the pace of bodily ageing. Depending on the individual, biological age can be either higher or lower than chronological age. Reducing biological age is one of the goals in many programmes aiming to help people alter their lifestyle or manage their health problems.
Many of the latest studies are focused on ways of slowing down and reversing the ageing process. Promising future applications include: reprogramming the ageing cells, using adult stem cells that are able to develop into another type of cell (pluripotency); reactivating the splicing factors in inactive cells, so that they rejuvenate and continue to divide like young cells; using courier viruses to smooth cell nuclei that wrinkle and stop DNA working properly; and replacing blood plasma with donated blood products.
Intelligence and cognitive ability
Neuroscientists are adapting their view of how the brain operates throughout life. Advances in neuroimaging and results from large studies show that some cognitive abilities may actually improve in middle and older age. They include: ability to distil the big picture; heightened emotion perception; ability to ‘read’ other people; adaptable brain networks; tendency to accentuate the positive; and ability to select positive goals, using knowledge, expertise and emotional intelligence.
These findings accord with the theory that crystallised intelligence, which is reliant on known facts and experiences, increases with age. Fluid intelligence, by contrast, revolves around the ability to think fast and abstractly and to solve problems without specific learning and prior experience. This is more evident in the brain activity of young people.
While IQ and a certain kind of intellectual ability have been highly regarded, some of the greatest human achievements have relied primarily on qualities such as curiosity, creativity and imagination. These traits are found in what scientists call ‘cognitive flexibility’, a skill that enables us to switch between concepts or adapt behaviour in a new or changing environment. It is key to creativity and includes more rational thinking, which helps people to develop strategies to overcome their biases. It is also associated with higher resilience to negative life events, as well as a better quality of life in older age.
Neuroscientists have also become interested in the highly beneficial effects of learning and listening to music. Playing an instrument can improve memory and build cognitive reserve. Practising music or singing activates the brain’s limbic centre and releases ‘happy’ chemicals, such as dopamine, especially when interacting with other people. It engages multiple brain areas – cognitive, sensory, motor and rewards systems – in ways that few other activities can match. The benefits may be especially high if you are a novice, or taking up music again after a gap.
Edited Autumn 2023