What factors determine longevity – and how can they be harnessed?

If you are lucky enough to live longer than the average person, you could be described as having longevity. Longevity is a combination of health and lifespan that is determined by a variety of factors. How to live longer is the age-old question that is fuelling the rapidly-growing longevity landscape, which combines research, development and investment to find longevity solutions. As birth rates decline and the aging population continues to grow globally, human beings’ eternal quest for longer and healthier lives has never been more important – but what determines longevity, and how can this be harnessed to help people live longer?

What is longevity?

Life longevity involves an interplay of health and lifespan, defined as the number of years an individual spends in good health and the length of time between birth and death. Life expectancy can widely vary depending on location, for example the life expectancy in Japan is 81 years compared with just 69 years in Swaziland. According to the Centers for Disease Control and Prevention, the average life expectancy in the United States is 78.8 years [1]. Individuals’ life expectancies are determined by a combination of different factors including sex, genetics, lifestyle and socioeconomic status. In the US, women on average live about 5 years longer than men, possibly related to the fact that they are generally less likely to take risks. Average life expectancy has been increasing in the past few centuries from around 30-40 years to over 80 years due to improvements in diet, medicine and public health. Currently, the title of oldest living person belongs to Kane Tanaka, a Japanese women who recently celebrated her 119th birthday.
Longevity tends to be centred in areas known as ‘Blue Zones’, where inhabitants live longer than average anywhere else on earth and where it is common to see nonagenarians leading active, healthy lifestyles. Blue Zones occur throughout the world across different cultural landscapes and include the Greek island Ikaria, Okinawa in Japan, and Sardinia in Italy to name a few. Whether human beings have a maximum lifespan is not fully understood, but some experts place maximum lifespan estimates at between 120-150 years, although this upper limit has not yet been reached [2].
Healthspan is also integral to longevity as most people never reach the optimum lifespan as they succumb to age-related disease. Since no one wants to live for a prolonged period of ill health, known as disability-adjusted life-years (DALYs), the longevity industry instead focusses on improving healthy life expectancy. Our health is determined by the same combination of genetic and environmental factors that determine lifespan. As we age, health gradually declines and our propensity for developing and dying from age-related disease like diabetes, cardiovascular disease and cancer increases [2].
Aging is an inevitable process that is caused by an accumulation of molecular and cellular damage in the body over time, known as the ‘hallmarks of aging’. The primary causes of this damage include genomic instability, attrition of the telomere endcaps in chromosomes, changes in our epigenetics and loss of protein homeostasis or ‘proteostasis’. Therefore, by solving health problems and slowing the speed of aging, we can improve life longevity.

Factors that influence longevity

Understanding what determines longevity is important as this knowledge can be applied to life-extending interventions. The rate at which we age is determined by a multifactorial combination of lifestyle, genetics and environment, with the two most influential factors being genes and environment. Genetics are difficult to control for; if one or both parents have a history of heart disease or cancer before the age of 50, there is an increased chance that their offspring will develop it too. Equally, life expectancy is to some extent determined by the age at which an individual’s parents died.
The environment is also influential on health and lifespan; a higher socioeconomic status is associated with better health outcomes and life expectancy. This increases the likelihood of access to healthcare, better nutrition and healthy living environments like green spaces and clean air. Living in closer proximity to pollution, as well as ambient air pollution in crowded cities can cause chronic health conditions. Some of these factors are out with our control, however there are several interventions we can take to lead a healthier life and increase the chances of longer longevity.
Lifestyle changes are the easiest way to maintain some control over longevity; for example, smoking, drinking excessive amounts of alcohol, physical inactivity and eating a poor diet all negatively impact longevity, but their effect can be reduced with the cessation of these unhealthy habits.

Understanding what determines longevity is important as this knowledge can be applied to life-extending interventions.
Photograph: Alexey Ruban/Unsplash

Improving health and lifespan

Life is innately finite, however experts in the longevity industry have sought to challenge this by combining innovations in life science and health care with business to disrupt aging and improve health and lifespan. Since there is no point in living forever when you are in a constant state of ill-health, longevity innovators instead focus on improving holistic health and slowing aging, in the hope that this leads to improved longevity and, some think, eventual immortality.
Unlike traditional medicine, longevity medicine is a growing field that aims to prolong the age of optimal performance over the entire lifespan. Considering the rate at which human lifespan has increased over preceding centuries, it can presumably be extended further. Understanding how we age can be used to implement real-life interventions with supplements, AI and diagnostics to improve health, aging and overall life longevity.