Age is also a matter of perspective

As the saying goes, you’re only as old as you feel. Well, it turns out that this is spot on. A person’s age is not simply a question of the duration of their life to date, but is instead affected by a number of factors, including a person’s perception of old age. IMPULS, an interdisciplinary research network based in Jena and supported by the Carl Zeiss Foundation, is examining how our various biological and psychosocial clocks »tick« and influence each other.

By Ute Schönfelder

For some people, it is demise by a thousand cuts: the gradual loss of hair, vision, muscular strength, physical fitness and cognitive abilities. For others, it is an enticing prospect comprising freedom, autonomy and inner peace. Everyone experiences the ageing process and old age in their own, unique way. Although nobody can escape the constant process of deterioration that inevitably ends in death, there are significant differences in how and at what speed people age.

»In this context, chronological age—that is, the duration of a person’s lifespan to date— only provides limited information about how old a person is perceived as being and how old they feel,« says age researcher Prof. Dr Christoph Englert. The biochemist is spokesperson of IMPULS, an interdisciplinary research consortium between the University of Jena, the Leibniz Institute on Aging – Fritz Lipmann Institute (FLI) and Jena University Hospital (see info box). »Although we can detect ageing processes at the biological level, in cells and in genetic material, these biological clocks do not reliably reflect a person’s age,« explains Englert. Instead, he contends, there is often an astonishing discrepancy between biological and chronological age.

Ageing as a process that can be shaped

»No human age group is as heterogeneous as the elderly,« emphasizes Prof. Dr Klaus Rothermund. The psychologist, who holds a Chair for General Psychology at the University of Jena, is also part of the IMPULS team. Rothermund previously led »Ageing as Future«, an international longitudinal project financed by the Volkswagen Foundation. He primarily identifies differences in the subjective perception of age but also in societal ageing norms. »Ageing is an individually malleable process and, in many respects, a self-fulfilling prophecy.« A person’s image of old age therefore has a decisive influence on the mental and, above all, physical condition in which they experience this phase of life.

However, the interaction and links between the two aspects of the ageing process—physiology and psychology—remain unclear. Researchers have examined age and its processes as predominantly separate issues to date. Now, however, Christoph Englert, Klaus Rothermund and their team have combined the two aspects to create a holistic model of the ageing process, which the researchers have now published in the journal “Gerontology”. »Gerontology«.

The novel aspect of the model developed by the Jena-based IMPULS team is that it provides interdisciplinary access to human ageing, along with its causes, consequences and subjective experience, by integrating all factors: biological, psychological, lifestyle-related and socio-cultural. »In doing so, we want to make it possible for us and other researchers to construct empirically verifiable hypotheses and identify targeted intervention measures that could increase an individual’s ability to resist ageing and mitigate its negative impacts,« says Englert. Over the long term the aim is for the theoretically possible life expectancy determined by an individual’s genetic make-up to be experienced in practice and in good health.

Cushioning ageing processes

»Our model distinguishes between the phenomenon of ageing, the subjective experience and the causes and consequences of these processes,« explains Rothermund. A major focus of the model is on the role of buffering mechanisms that influence physical and mental health and thereby regulate the ageing processes. »These include biological repair mechanisms and how a person adapts to their situation in life,« adds Englert.

The biological buffering mechanisms that counteract the ageing process include, for example, DNA repair and cell renewal, which ensure that tissues and organs function properly. The buffering mechanisms in turn depend on individual behaviour, which includes physical exercise, healthy nutrition, but also avoiding harmful influences such as smoking and excessive sun exposure.

In addition, certain social aspects can cushion the ageing process: people who maintain wide-ranging social relationships and play an active part in society age more slowly on average than people who do not. The efficiency of these mechanisms varies from person to person and over the course of a person’s life, which is why people age at different speeds.

Extensive test subject study

In the next phase, the researchers hope to apply their model in an IMPULS study and find out whether a person’s perception of age corresponds to their ageing at the biological level. To this end, they are analysing blood and saliva samples from hundreds of subjects whose perception of ageing and attitude to the process have already been examined over several years in the previous »Ageing as Future« study. »It will be interesting to see whether, for example, a positive attitude towards old age is reflected epigenetically in the subject’s cells or whether epigenetically young people also defy the psychological effects of old age,« as Rothermund anticipates. The team expects the study to produce results by early 2025.

One thing that Englert and Rothermund are sure about, however, is that healthy ageing is also a societal challenge. »Older people in particular benefit from wide-ranging social relationships and participation,« underscores Rothermund, who, as a member of the expert commission, also co-authors the current German Federal Government’s Report on Ageing.

At present, however, Rothermund says that older people often feel increasingly pushed to the fringes of society as soon as they leave the world of work. This is not just a social problem, he says, but a health problem. »The feeling of no longer being needed—which many people get when they enter retirement—can have a considerable impact on physical and mental health and, consequently, accelerate the ageing process,« says Christoph Englert.

The IMPULS project has been financed by the Carl Zeiss Foundation since 2021 as part of its »Breakthroughs« funding programme. The IMPULS project’s full, official title is »Identification and manipulation of the physiological and psychological clocks of lifespan«. The project team includes experts from the fields of biochemistry and epigenetics, medicine, neuroscience, nutritional science, pharmacy, epidemiology, bioinformatics, biostatistics, gerontology, psychology and the social sciences.