Over the last two centuries, global life expectancy has increased from 29 years to over 72 years of age. In 2016, The World Health Organisation estimated that since the turn of the millennium alone, average life expectancy around the world increased by 5.5 years; the fastest increase since the 1960s. Despite this progress and other positive developments in human lifespan, age remains a sensitive and uncomfortable subject for many people. A subject about which enquiring is still impolite and lying commonplace. But are we right to feel such discomfort at disclosing the number of years that have elapsed since our birth?
We’ve all heard the phrase ‘age is just a number’. But, age is actually 2 numbers. The first is the one nearly all of us identify with (or falsify), chronological age. How long we’ve been alive on this earth. The second number, less common but more interesting, is what scientists refer to as our biological age. How old our body seems; like an adult who’s lived for 50 years but has the physical condition of a 25-year-old. Biological age, sometimes called ‘true age’ or ‘real age’, is determined based on several factors. These include: how healthy we are, how fit or in shape we are, our mental cognition, and even our emotional health. Essentially, it is a measure of how well we are in both mind and body.
This new way of determining age is broken into two categories: health span and disease span. Our health span is the number of years we live free from diseases which, needless to say, affect the quality of our lives. Whereas disease span defines the number of years spent with a noticeable decline in health. This kind of information and analysis is not just for theoretical intrigue. Insurance companies are increasingly less interested in our chronological age, instead turning to more specialised profiling and statistical modelling in order to calculate an individual’s ‘actuarial age’. Better known as ‘life expectancy’. These mathematical computations discovered that people of vastly different chronological ages could in fact have the same number of actuarial years remaining (in their life expectancy projections). Put another way, a 40-year-old is not necessarily a better insurance proposition than an 80-year-old.
The recent classifications of health span and disease span came after the discovery of epigenetics; hailed by the scientific community as the most important discovery since DNA. Epigenetics is the study of changes in organisms caused by modification of gene expression, rather than alteration of the genetic code itself. The ways in which our environment and behaviours change how our genes work. Unlike genetic changes, this doesn’t involve altering our actual DNA sequence but, rather, how our body reads a DNA sequence. Epigenetics proves that we are not in fact destined to live out the same disease span as our ancestors. Though certain illnesses are coded into our genetics, it is our environment and lifestyle that determine whether or not these disease promoting genes are activated. So much so, that scientists now believe that less than 30% of our longevity is controlled by genetics, whilst 57% (the highest proportion) is attributed to our lifestyle.
We can’t turn back time and we can’t get any younger… Chronologically that is. Biologically, however, that’s exactly what we can do! We can reduce our biological age if we choose to make longevity a priority and take the necessary steps towards achieving it. These steps include: a healthy diet, limiting toxins, minimising stress, plentiful exercise, adequate sleep, physical conditioning, and regular health check-ups. It is, ultimately, the interaction of genes and environment that determines our rate of aging. Thus, it is essential that we take the time to understand our genetic history and individual bodily needs. This will enable each of us to take the right approach, including the right preventive measures, to suit our own unique pairing of genetic make-up and environment. After all, age is not a fixed number. Rather, it is a continuously evolving estimation of the interplay between three key elements: genetics, health, and lifestyle.