Some of the decay of aging is going to happen no matter what you choose do on a day to day basis. Your metabolism is running all the time, and it constantly generates damage as a byproduct of that activity. Metabolic waste accumulates in long-lived cells and in the extracellular matrix. Stochastic DNA damage builds up in the cell nucleus to raise cancer risk and in mitochondria to cause dysfunction there. Cells react to damage and dysfunction by becoming senescent or declining in activity. You could live the perfect life and all of this and more will happen regardless: it is wear and tear as a consequence of the evolved structure of your biology.
There is plenty you can do to hurry this along, however. Happenstance and choices made can accelerate existing forms of damage or add new types of damage that make the situation worse, bringing you to a state of being physically older at a given chronological age than would otherwise have been the case. We tend to live longer than our ancestors in part because we've managed to eliminate a large fraction of the burden of infectious disease and the long-term harm it causes to survivors, for example. Our wealth and technology also provides the opportunity to become fat and sedentary in greater numbers, however, which accelerates the pace of damage, and smoking of course merits a chapter of its own in the annals of killing yourself slowly.
So there is primary aging and there is secondary aging. Primary aging is the damage you can do next to nothing about at the moment, and will only be impacted by the development of therapies capable of repairing the accumulation of damage that causes degenerative aging and all of its attendant medical conditions. Secondary aging is what you do to yourself, most people through some combination of excess fat tissue, lack of exercise, and smoking, and is consequently under your control. The balance of influence here is obviously biased towards primary aging in the end: you can't make lifestyle choices that reliably allow you to live to age 90 in the environment of today's medical technology. Three-quarters of people with the best health are dead by that age, and only medical progress will change that statistic.
You can, however, make simple choices that shift your life expectancy across the range of a decade, out there in the future ahead. You can change your future health for the better and reduce your expected medical expenses at the same time. It seems worth making that effort, especially at this time of very rapid development in biotechnology: a few years here or a few years there might mean the difference between being alive to benefit from the first effective clinical rejuvenation treatments, or dying just on the cusp of that new age of medicine. You never know, and certainly there are those of us trying to speed up the development of those rejuvenation treatments.
Here is an interesting approach to putting some better numbers on the split between primary and secondary aging. All too many people focus on secondary aging when it comes to their health, and that is where their concerns and vision stop. But if we want to see significant progress in funding and support for effective treatment of the causes of aging, then it is very necessary to convince more of these individuals that they are overlooking the most important part of the problem:
Non-communicable chronic diseases are the greatest cause of mortality in the world, yearly claiming more than 34.5 million lives worldwide (66% or 2/3 of global deaths, or nearly 100,000 deaths daily). Hence major efforts are directed toward their alleviation. Yet, a crucial point is often missing in these considerations, namely, the due emphasis on the fact that these diseases are age-related diseases, and their main risk factor is not necessarily related to environmental risks or life-style choices, but to the aging process itself! There is an appreciation that the incidence of non-communicable diseases increases with age steeply, unlike the effects of other environmental and life-style factors whose influence may be considered steady. Yet, the exact weight of age in relation to other risk factors remains uncertain. Hence, there is a need to be able to determine this weight in order to provide a fuller diagnostic and prognostic assessment for age-related diseases and design interventions that would be able to affect the entire array of risk factors.
Such an ability would be especially valuable for heart disease, the main age-related disease and cause of death in the world. As of 2010, it was estimated that the cardiovascular and circulatory diseases represented the largest proportion among all causes of mortality. Yet, it is also known that cardiovascular diseases, and ischemic heart disease in particular, can be highly susceptible to therapeutic and lifestyle interventions, capable of dramatically extending the health and longevity of the subjects. Hence it is of primary importance to be able to assess the entire array of risk factors as well as the effects of therapeutic interventions on the risk factors, either individually or in combinations, including age. If age is the main risk factor, then it may well be that the primary target of the therapeutic and lifestyle intervention would be the aging process itself.
Here we apply the information theoretical measure of normalized mutual information (uncertainty coefficient) to determine precisely the weight of various risk factors in heart disease, and the particular weight of age as a risk factor, individually and combined with other factors. We show that individual parameters, including age, often show little correlation with heart disease. Yet in combination, the correlation improves dramatically. For diagnostic parameters specific for heart disease the increase in the correlative capacity thanks to the combination of diagnostic parameters, is less pronounced than for the less specific parameters. Age shows the highest influence on the presence of disease among the non-specific parameters and the combination of age with other diagnostic parameters substantially improves the correlation with the disease status. Hence age is considered as a primary "metamarker" of aging-related heart disease, whose addition can improve diagnostic capabilities.
There is a growing realization that a promising and cost-effective strategy to combat severe non-communicable diseases is to give a greater focus of health research from attempting to address individual diseases and symptoms to addressing their underlying root cause and main risk factor - the degenerative process of aging. Such an approach has already yielded in the past valuable strategies to combat non-communicable diseases. Historical examples include probiotic diets, cell therapy and adjuvant immunotherapy that were born from biological research of aging. Further emphasis on treating, delaying or even reversing the seemingly "general" and "systemic" biological processes of aging may likely produce not just a general improvement of the functional state of the aged, but also further advances in the treatment of specific age-related non-communicable diseases, such as heart disease. The current work, for the first time quantitatively demonstrating the weight of age (aging) as a risk factor for heart disease, gives further support to this approach. It further emphasizes the need to intervene into the basic aging processes for developing effective therapies for age-related diseases.