What is the future of human life expectancy?

1. How long could humans live?

Over the 20th century, life expectancy in high-income nations rose, leading some scientists to claim that radical extension of human life could be possible.^[1] A 2009 study in the Lancet argued that most babies born in the UK after 2000 would see their 100th birthday.^[2] However, from the 1990s onwards, increases have been slowing.^[3]

In October 2024, an article in Nature Aging said that radical extension to human life expectancy is “implausible in this century”.^[4] The study used data up to 2019 because of the dip in life expectancy caused by the Covid-19 pandemic. The authors argued that “humanity’s battle for a long life has largely been accomplished” with a century of public health and medicine “allowing humanity to gain the upper hand on the causes of death that have, thus far, limited human lifespan”. They stated that while the first longevity revolution had ended, a second revolution could come when and if science can successfully slow biological ageing in humans.

Reporting on the study, the New Scientist gathered a range of views from researchers.^[5] Jan Vijg at the Albert Einstein College of Medicine, New York, expressed the view that “there’s some sort of biological limit” that prevents humans living any longer. However, Gerry McCartney at the University of Glasgow said the slowing growth in life expectancy over the past decade may be attributable to cuts in social benefits and healthcare services and increased poverty. With different policy decisions, he argued, life expectancy could continue increasing.

Some scientists have argued that there is potentially no upper bound to the human lifespan. Laura Deming, founder of longevity research investment fund Age1, wrote an open letter in September 2023 which said that ultimately, with investment and ambition, people could be given “full agency over the number of healthy years they’d like to live”.^[6]

2. Is the second longevity revolution imminent?

Age1 notes that there are currently no approved medicines for holistic ageing-related interventions.^[7] However, a range of research projects are underway to understand more about ageing and potential ways to extend the human lifespan, or increase the number of years lived in good health: the ‘health span’.

An article from researchers at the University of Cambridge explains that bodies undergo a raft of biological changes over time, and there is not yet consensus on where medicine is most likely to be effective.^[8] One broadly accepted contributor to ageing is the gradual accumulation of mutations in cell DNA. External factors like smoking, sunrays and pollutants can also damage cells.

Ongoing work at Cambridge includes geneticist Alex Cagan’s studies on long-lived animals like whales, elephants and ‘immortal’ jellyfish (which can reverse their lifecycle). He is exploring whether they have evolved a better ability to repair DNA damage, with a view to eventually applying the science to human life.

A special issue of the Journals of Gerontology: Biological Sciences in September 2024 focused on geroscience, the field of research exploring interventions to slow or reverse molecular drivers of ageing.^[9] One article looked at the challenges of conducting and getting approval for clinical trials for potentially gerotherapeutic drugs.^[10] Issues included communicating to regulators to whom the drug might ultimately be made available. Drugs are usually studied for a group of people with a particular diagnosis, rather than targeted at extending the lifespan of any healthy person.

Much of the research on longevity has taken place in worms, fruit flies and mice.^[11] Short lifespans mean human researchers can study whole lifecycles and see if certain interventions extend them. In February 2024, a study published in the journal Cellular Reprogramming indicated that gene therapy could increase mice lifespans by an average 109%, and reduce their frailty in the latter part of their lives.^[12]

As well as studying medications which could extend life, scientists are exploring treatments that could work across multiple bodily systems to increase how many years are lived in good health. For example, in February 2024, the Lancet: Healthy Longevity published a systematic review of studies (in humans) involving the medicine rapamycin (which acts on mTOR, a protein that regulates cell growth and division).^[13] The researchers found that it improved physiological parameters associated with ageing in immune, cardiovascular and skin health, but showed no effect on other systems.

3. Are any treatments available now?

While molecular geroscience remains largely in the lab, MIT Technology Review has discussed the rise of ‘longevity clinics’.^[14] These facilities conduct a range of medical tests and then usually recommend diet, exercise and lifestyle changes with the intention of extending a client’s lifespan. The MIT article noted that the clinics have no set standards, so range from “high-end spas offering beauty treatments to offshore clinics offering unproven stem cell therapies”. It said that the clinics are “expensive and currently only cater to the wealthy”. One clinician quoted in the article envisages that within a decade, a standardised, evidenced longevity protocol will be available from GPs.

3.1 What is the current state of life expectancy in the UK?

The Office for National Statistics (ONS) has estimated the life expectancy at birth for babies born from 2021 to 2023 in England and Wales:^[15]

• England: 79 years for males and 83 years for females
• Wales: 78 years for males and 82 years for females

The latest figures available for Northern Ireland and Scotland are for the 2020 to 2022 cohort:^[16]

• Northern Ireland: 78.4 years for males and 82.3 years for females
• Scotland: 76.5 years for males and 80.7 years for females

After increases up to 2019, life expectancy at birth in the UK has dipped to near the level it was in 2010.

The ONS also publishes data on how many people are in the oldest age groups.^[17] In 2023, the estimated population aged 90 years and over in England and Wales was 551,758, including an estimated 14,850 centenarians.

A King’s Fund long read on life expectancy in England highlighted an “urgent” need to address inequalities: life expectancy in the most deprived area of England is 10.3 years lower for males, and 7.1 years lower for females than in the least deprived area.^[18] Also, life expectancy without acquiring a disability is on average 20 years shorter than total life expectancy.

In May 2024, the Royal Society also observed that while life expectancy in the UK has increased overall, healthy life expectancy has not increased at the same rate.^[19] It said:

This situation is particularly concerning in regions where high levels of deprivation and an older demographic converge, further exacerbating health issues. Caring for an ageing population brings several challenges for the social and healthcare system, including increasing pressures on the NHS and various sectors of the economy.^[20]

The Royal Society argued that there is “an urgent need to translate the current understanding of geroscience into extended healthy lifespan”.^[21] Using geroscience to reduce the instance of chronic disease and frailties in later life would, the society said, ease strain on the NHS and enable more people to stay in the workforce longer, contributing to the economy.

4. How can society adapt to changing demographics?

Some researchers have questioned whether the world can cope with significant population expansion in the oldest age groups. In a Science News article, ethicist John Davis questioned whether large increases in lifespan could cause “really spectacular increases in population on a planet that I personally feel is already overloaded”.^[22]

An editorial in the Lancet: Regional Health in December 2023 suggested how Europe might proactively plan for an increased population in older age groups.^[23] It said that in the short-term, new clinics should address common non-communicable diseases (like heart disease or diabetes), focusing on prevention, symptom management and rehabilitation. The editorial also advocated for nations to make sure treatments are accessible and affordable for issues that can impact independence, like hearing loss and eyesight deterioration.

In addition, the article argued that communities should be set up to be ‘senior-friendly’. That could include a more robust network of care services, recreational activities, affordable housing, support and social benefits, and an extensive public transport network. Long-term, the article advocated increasing the birth rate to bolster the working population, as well as improving the health of migrant workers.

The United Nations published a paper in January 2024 that draws attention to the fact that many of the least-developed countries are still in the early stages of seeing lifespans increasing.^[24] These countries, the UN said, should focus on boosting economic development while setting up the services and support that will be required as demographics change.

Sarah Harper, director of the Oxford Institute of Population Ageing, wrote for Age International about the benefits of an ageing population.^[25] Ms Harper emphasised that older adults continue to participate in the workforce globally, as well as having vital roles in community organising and caring for family members. In chapter two of the 2024 book ‘A Research Agenda for Ageing and Social Policy’ she and Yanan Zhang argued that the rhetoric of an “ageing crisis” is simplistic: appropriate long-term policy responses can create a “demographically resilient” society, “ensuring well-being and prosperity for all ages”.^[26]

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Cover image by Terrah Holly on Unsplash.