Aging is characterized by a progressive functional decline in physiological functioning that leads to increased vulnerability to disease and death. This deterioration is the primary risk factor for all chronic diseases, including cancer, diabetes, cardiovascular disorders, and neurodegenerative diseases. In fact, successful aging is defined as maintaining high physical, psychological, and social functioning in old age without major diseases. Throughout human existence, there has been a quest to find a “fountain of youth” to combat the negative effects of aging. Over the years, there have been a number of movements attempting to classify aging as a disease. In 2018, the World Health Organization added an extension code in the latest version of the International Classification of Diseases for “aging-related” diseases; that is, diseases that occur and worsen as we age.
But is aging truly pathologic? Old age isn’t abnormal and everyone is subject to it unless they die prematurely. So, a better approach than classifying it as a disease, is to try and address the underlying mechanisms that cause aging and age-related cellular deterioration. That is, successfully managing the aging process to reduce risk and improve healthspan (the time you remain healthy).
An understanding of a critical aspect of cellular degeneration was uncovered in 1962 when a UCSF professor, Leonard Hayflick, discovered that typical human cells had a limit to how many times it could divide before becoming senescent, or exhausted. Along with that discovery, Hayflick figured out that telomeres, which cap the ends of chromosomes and prevent them from fraying, much like plastic tips preserve the ends of shoelaces, shorten each time a cell divides. When the telomeres get short enough, a cell stops dividing.
More recently, researchers have identified nine “hallmarks of aging” that include disrupted cellular communication, genome mutations (associated with cancer), telomere shortening, epigenetic alterations, degradation of cellular proteins, dysregulated cellular nutrient sensing ability, impaired mitochondrial functioning, cellular senescence (when cells stop dividing and growing due to age), and stem cell exhaustion. These hallmarks are all inter-related, occur in every human and often occur simultaneously, which makes attributing the overall cause of aging to any one of them problematic.
As stated earlier, aging is the biggest risk factor for all chronic diseases. It is also clear that different people age differently. Identifying which of these hallmarks may be impacting your life can be a crucial barometer of your health risks. Two simple tests, telomere testing and epigenetic testing are available. Both are simple blood or saliva tests that tell you a measure of your biological age, a biomarker that provides a window into physiological functioning at the cellular level.
Knowing your biological age is a big step in understanding the entirety of your health profile. Because biological age can shift, seeing changes over time is vital to understanding what is good and bad for your health. Knowing where you stand and the habits that can affect your biological age can be a key component, together with healthy living, of improving your overall health.