What Is Your Biological Age?

"Aging" is one of those terms that evoke a multitude of - mostly negative - connotations, as it applies to everyone and everything in the universe. While the definition of Aging may seem obvious, its highly commercialized Antonym: Anti-Aging" is more ambiguous, if it even exists. People tend to see their lifespan ilike an hourglass, a countdown of sort and everyone seems interested to their elapsed time. There is a growing trend in people asking to know their biological age, with the expressed or implied expectation to hear that they are biologically younger than their calendar age. This movement has spawned whole new industries and revived old ones to cash in on this development.

By "aging" we usually allude to the biological process of growing older in a deleterious sense. That is why - the longer we have aged, the more we seek to forestall agings' ultimate terminal effect.

To begin with, we would have to define human lifespan, life expectancy and longevity, or simply: how many years is a human life? From there on interests diverge, social economists break it down to productive years and dependency years. The political science concerned with Aging is now enacting Anti-Aging by raising the retirement age. Their theoretical, mathematical tool to determine biological age is the Gompertz equation, which describes the increase of mortality over time., The Gompertz relationship can be used to calculate the change in life expectancy corresponding to a particular standardized mortality ratio "SMR" over a greater range than have previous methods, and, although subject to some uncertainties, can provide a quick method of judging the change in life expectancy that is associated with a given SMR value. While this model may be useful in population studies, the individual wants to know their reversed elapsed time in lifespan, expressed in terms of how much longer can they live a productive life, and by how many years can they exceed their predicted number of years..

A dynamic human life in a highly volatile environment poses an enormous challenge to any credible predictive measure in the first place. People are lead to believe that "Anti-Aging Medicine" is able to determine their biological age and their rate of aging, virtually at the blink of an eye. There is widespread hyped but unfounded believe that a single DNA sample can do that. The reality is that any specimen analysis at a given time can only process what it sees at that moment. It's like if life is a movie, you are looking at a snapshot, even if you are taking a snapshot every few seconds, you still don't see the movie. So in some cases it may be indicated to act upon a snapshot, like deciding to change your hairstyle, for instance; but you would want to preview a longer trailer of the movie before making irreversible decisions - you can never take back a surgery.

Skin elasticity measurement as a biomarker for biological age determination is widely used, most notably within the Beauty Industry for obvious reasons. The Aging of Skin connective tissue is the most visible marker for aging and that explains its popularity: The connective tissue of the skin is composed mostly of collagen and elastin. Collagen makes up 70-80% of the dry weight of the skin and gives the dermis its mechanical and structural integrity. Elastin is a minor component of the dermis, but it has an important function in providing the elasticity of the skin. During aging, the synthesis of collagen gradually declines, and the skin thus becomes thinner in protected skin, especially at about retirement age. Mechanical properties of skin (e.g., elasticity of skin) will change due to lifestyle and environmental exposure factors, such as disease, stress, or dehydration. Several factors contribute to the aging of the skin. where collagen or elastin are deficient, leading to accelerated aging, evident by wrinkles and sagging of the skin. Excessive tanning and exposure to ultraviolet radiation causes skin to look prematurely aged. These photoaging effects can be seen as early as the second decade of life. There is another problem with this highly subjective method of age interpretation: when the body becomes dehydrated as a result of an illness (e.g., ones that cause diarrhea) or reduced liquid intake (e.g., famine or marathon running), the skin becomes "plump and does not snap back when pinched.

Telomerase is the latest subject of scientific - and Media - focus: a predictor of health and aging, a comparatively obscure enzyme called telomerase might eclipse the importance of much more famous molecules – cholesterol, for instance. Telomerase acts on DNA at the ends of chromosomes, called telomeres. Telomeres might be a link between stress, diseases associated with aging and aging itself. The level of telomerase activity is important in determining telomere length in aging cells and tissues. Senescence is the scientific term for cellular aging,  the process by which a cell becomes old and dies. It is due to the shortening of chromosomal telomeres to the point that the chromosome reaches a critical length. In a body of vitality a cell becomes immortal and constantly produces new cells. When the body loses its vitality (aging), the cell stops producing new cells and dies. Being able to make the body's cells live forever certainly creates exciting challenges and fuels yearnings for immortality. However, the science has not yet progressed to the point where
we can measure our telomere lengths and thereby derive our biological age relative to chronological age.

Lab tests are the most common approaches to determine age and aging; they are favored within the clinical realm, again for obvious reasons. However, these are not at all new and there is neither an unequivocal understanding of which biomarkers to use, nor how to evaluate these in a normative fashion. Typical indicators used are CRP for Inflammation, cholesterol, hormones, blood sugar, cell function, blood pressure, There are almost unlimited other available analytes, such as Homocysteine, kidney and liver function, brain function and so forth. Despite the fact that the more samples analyzed, over a longer timespan can produce a more reliable blueprint, the processing and interpretation of the information is arbitrary at best. One can easily imagine the challenge put on the medical community to agree upon which markers to use and to establish a normative measuring and scoring system such that adding up all of the results for a complete body of tests could produce a "biological age". But that would requires the medical disciplines to unite in weighing and validating each of these factors and agreeing on a benchmark "age index".

However, some scientists from The University of North Carolina believe to have found the "silver bullet" in a single blood test that can measure the body's rate of aging at a molecular level.  According to their research, the concentration of a protein named "p16INK4a" significantly increases in aging tissue. Though even if this method will establish itself as a method for assessing the rate of aging, determining a person's biological age versus their calendar age is a different challenge - but that is what people want to know.

The fact that we can't agree on the standard or method to articulate a biological age shouldn't discourage us from trying, until now, we haven't even been able to agree on the spelling of the term, are we Aging or Ageing?

References:

Gompertz equation
Telomerase
Measuring Aging