Scientists disagree over many issues relating to aging. But there is a general consensus as to what the aging process is.
The aging process is characterized by the progressive physiological deterioration at the cellular level of all organs and systems in the body. The damage accretes so slowly that we hardly notice it. This physiological deterioration commences in most humans while they are still in their 20s. We’re not just slowing down physically; all of our organs are wearing down. For example, scientists have confirmed that physical deterioration of the brain commences in typical healthy humans before they reach the age of 30. Other studies have confirmed that all organs and systems exhibit observable physical damage at a relatively young age.
Over the years, this physiological deterioration progresses to the point where disorders or functional declines become apparent. Among the functional declines resulting from this physiological deterioration are longer reaction times, a lower metabolic rate, declines in homeostatic capacity, declines in memory and cognitive functions, declines in sexual activity, declines in kidney, pulmonary, and immune functions, declines in exercise performance and multiple endocrine changes.
At some point (which may be decades later), as the physiological deterioration leads to further and further impairment in function, an organ or system malfunctions to such an extent that the condition is recognized as one or more of the aging-associated diseases. Chronic degenerative diseases (cardiovascular disease, osteoporosis, dementia, etc.) are generally the result of this accreting deterioration causing a progressive loss of function in all of the body’s organs and systems. Functional impairment starts at a very young age, but the condition is not recognized as a disease until a weak link fails. Inevitably, as a chronic degenerative disease continues to progress, there will be a catastrophic failure of some organ or system, and the subject dies.
Historically, doctors have focused on specific diseases. They try to prevent or ameliorate the effects of cardiovascular disease, or dementia, or osteoporosis. More recently, there has been a growing recognition that all of the chronic degenerative diseases have the same root cause. A group of academicians and scientists have argued, with increasing success, that the only way to effectively combat any chronic disorder is to prevent or reverse the underlying cause. They identify that underlying cause as the “aging process itself.” That’s why there has been a lot of attention in the press of late regarding efforts to delay or reverse aging. The idea is that if you can delay the aging process, you can delay the onset of all of the aging related disorders.
Although there is no consensus on the issue, most scientists would agree that the cause of the physiological deterioration is entropy. Entropy is embodied in the Second Law of Thermodynamics. In common parlance, entropy is a characteristic shared by all animate and inanimate objects in the universe -- everything deteriorates and wears out over time. Even in the absence of outside forces, everything deteriorates, collapses, breaks down and wears out. Living organisms, such as humans, are not exempt. Entropy, as embodied in the Second Law of Thermodynamics, is inevitable and irreversible.
An important concept that is accepted by most academicians is that all functional modalities are affected by the aging process in pretty much the same way. There may be variances as to which function fails first (the weakest link), as the result of genetic predisposition, lifestyle and medical interventions. But generally someone who is very advanced in the aging process is suffering moderate to severe dysfunctionality over multiple modalities. Significantly improving functionality in any modality is not possible without remedying the underlying cause (physiological deterioration). That implies that one cannot significantly improve functionality in any modality with significantly improving all of them. And that’s what the scientists who are trying to reverse aging are trying to accomplish.
Decline in exercise performance is one obvious example of functional impairment resulting from the aging process. The decline is the result of the deterioration of the skeletal muscle system. There is no particular disease that is associated with this deterioration, but there is no mistaking the fact that most elderly humans suffer significant physical impairment. The thing is, we absolutely do know how to improve functionality in the exercise performance modality. Anyone of any age who undertakes a training regimen that involves frequent intense exercise will substantially improve his or her exercise performance.
Combine the last two paragraphs. You cannot improve the functionality of one modality (such as exercise performance) without improving the functionality of all (e.g., cardiovascular performance, brain function, etc.). And the mechanism has to be the repair and rejuvenation of the underlying physiological deterioration. The point is that the benefits of intense exercise go well beyond the long accepted “training effect.” When we engage in intense exercise, among other things, we activate processes that rejuvenate and repair the accumulated physiological deterioration that leads to the loss of function across all modalities. As the scientists predict, improving one modality (functionality of the skeletal muscle system) improves all modalities.
As humans age, they typically exhibit both the functional declines described above and certain cosmetic changes. It’s critical to keep in mind that these are separate phenomena. Evolution cares a great deal about humans maintaining functionality throughout their lifespans, and has provided us with a process that accomplishes that purpose. That process does not have a direct effect on cosmetic changes such as hair thinning and graying, losing teeth or the appearance of wrinkles. Similarly, if a miracle anti-aging skin cream performed as advertised, one would not expect it to have a beneficial effect on osteoporosis or dementia.