The components of regimen for prolonging survival and decreasing mortality rate are reviewed.
The role of meditation and meditation-like practices in reducing oxidative stress and other forms of life-span reducing stress, as well as in reducing metabolic rate to extend longevity is analyzed.
Physical aerobic exercise and special dietary programs with calorie restriction are also mentioned as the other primary components of the life-span prolonging regimen.
Several studies on meditation have demonstrated effects that are consistent with a lengthening of both the (mean) life span and the "health span."
Most recently, a large-scale epidemiological study comparing hypertensive practitioners of Transcendental Meditation (TM) with matched hypertensive controls over two decades revealed a 23% decrease in all-cause mortality (primary outcome), while secondary analyses showed a 30% decrease in the rate of cardiovascular mortality and a 49% decrease in cancer-related mortality.
Other studies on TM that have attempted to evaluate practitioners against controls with respect to putative aging-related biomarkers, including blood pressure, lipid peroxide levels, and standardized sensory and cognitive measures have found meditation to be a successful anti-aging intervention according to such criteria.
Other studies have proposed a role for meditation in significantly reducing age-related increases in blood pressure and in prolonging survival, but these studies did not explicitly parse out the effects of meditative practice from other related factors, such as cloistered seclusion and social support.
The mechanisms by which meditation may retard aging and prolong survival and the health span are currently under investigation.
As with a number of other putative anti-aging interventions, evidence has pointed to the counteracting the oxidative stress and other (e.g., nitrosative, mental) forms of stress, and inflammation, and to general promotion of innate reparative and regenerative processes.
McEwen, Sapolsky, and others have summarized evidence for the role of psychological or emotional stress in the acceleration or exacerbation of fundamental aging processes.
Recently, a landmark study conducted by Elizabeth Blackburn and colleagues demonstrated that the chronic and severe emotional stress induced in caregivers of severely ill family members actually led to telomere shortening in the caregivers; moreover, the data indicated that the degree of shortening actually correlated with the degree of perceived stress.
Furthermore, another recent (pilot) study by Waelde et al. at Stanford University demonstrated that meditative practice could significantly counteract the deleterious effects of caregiver stress in practitioners, as evaluated with standard scales of anxiety and depression.
Oxidative stress is considered a primary agent of aging in many leading theories of aging, and is conceptualized as a product of oxygen radical formation during normal metabolic functioning and/or resulting from deficiencies in protective endogenous antioxidant, free radical scavenging capacities.
Several studies on meditation have demonstrated reduced indices of oxidative stress during meditation as measured by reduced levels of lipid peroxides, malondialdehyde concentration, and urinary vinyl mandelic acid levels, and such reduced levels of oxidative stress have been hypothesized to reflect a slower rate of aging.
In particular, the idea that normal metabolic functioning, which causes oxidative radical byproducts, in turn causes aging over time (i.e., the "rate of living" theory of aging), is currently a subject of broad and intense debate, with proponents and critics offering many explanations to resolve apparent inconsistencies and contradictions in the data.
If, as some contend, reduced metabolic rate leads to the (relative) retardation of aging, then the practice of the classic meditative regimen may indeed be associated with significant retardation of aging and/or extension of life span and health span on the basis of much data on the metabolism-lowering effects of meditation.
Of particular interest in this regard are studies by researchers from Stanford, Harvard, Rockefeller University, and other research institutions on the special ability of some long-term, virtuoso yoga practitioners to induce and maintain profoundly lowered metabolic rates during meditation, with reductions ranging from 38–64% below resting levels! Such lowered metabolism is actually within the range of hibernating animals, and hibernation has been associated with extended longevity in some studies because of lowered metabolism, according to some investigators.
Several studies of meditation and meditation-like practices (self-hypnosis; systematic stylized forms of relaxation, etc.) have also demonstrated a range of anti-inflammatory effects and dampening of inflammation-like immune processes, and much recent research in gerontology has focused on elucidating the aging-accelerating effects of chronic inflammation and related immune processes.
According to these studies, meditation and such meditation-like practices, may lead to reductions in levels of tumor necrosis factor-? (TNF-α), interleukin-2 (IL-2), interferon-γ (IFN-γ), as well as reduced inflammatory/immune responses to a range of antigens, allergens, and irritants, including lipopolysaccharide (LPS), histamine, capsaicin, varicella zoster, Mantoux antigen, dinitrochlorobenzene (DNCB) and diphenylcyclopropenone (DCP), ultraviolet B (UVB), and standardized thermal stimulation.
In addition, anti-inflammatory substances such as IL-4 may be upregulated during meditation.
In fact, recent studies have shown that meditative practices upregulate other important endogenous substances possessing not only anti-inflammatory properties, but antioxidant and anti-stress, as well as general longevity-enhancing, regenerative properties, namely melatonin and DHEA.
The anti-inflammatory, antioxidant, and anti-stress effects of these latter two substances are well established.
Furthermore, the other primary components of the regimen – physical exercise and special dietary programs – appear in general to possess anti-aging effects that are similar to those achieved by meditation.
Aerobic exercise of moderate intensity studied in the Western clinical/laboratory setting is physiologically similar to that of the classic yoga-meditational regimen; that is, we can cite in particular the dozens to hundreds of rapidly performed repetitions of prostrations, in which the practitioner from an erect standing position bows, then "prostrates" completely on the ground, before rising back up to a fully erect standing position.
While there are no known studies to date that indicate that aerobic exercise can extend the maximum life span in animals or humans, studies have shown that aerobic exercise can increase mean life span in laboratory animals, and certainly the health span in animals and humans.
Exercise intensity, duration, frequency, and other factors appear to play important roles in anti-aging outcomes, as does the role of training.
These salubrious effects appear to be most likely due to stress-reducing, anti-inflammatory, and antioxidant effects.
Such effects may in turn be mediated by increases in the activity of melatonin, DHEA, and ILs–10 and among others; while the exercise-induced enhancement of the latter three substances appears to be robust as well as replicated, the data with respect to exercise and melatonin appear to be more equivocal.
It has been well known for decades in gerontological research that restriction of caloric intake (calorie restriction or CR) by between roughly one- and two-thirds, while maintaining nutritional balance ("undernutrition without malnutrition," maintaining necessary vitamins, minerals, protein, etc), can extend the mean and maximum life span of model organisms, and delay or prevent degenerative physiological changes and age-related disease.
It is less well-known that the "classic" monastic or ascetic diet is actually similar or identical to the standard CR diet, and is focused on nutrient-dense staples including beans and legumes (such as "lentils"), nuts and seeds, milk, yoghurt, and other nutritious dairy products, and fruits and vegetables, often taken in one or two meals per day (caloric restriction of roughly one- to two thirds).
While most research has been conducted on model organisms (yeast, nematodes, Drosophila, rodents), nonhuman primate studies, and several recent human studies, have recently been undertaken.
While these latter studies are not of sufficient duration yet to determine whether calorie restriction will extend the mean or maximum life span of nonhuman primates and humans, data already generated have demonstrated apparent aging-retarding changes consistent with the results in model organisms (including reductions in blood glucose, insulin resistance or its analogues, blood pressure in higher organisms, etc.) in which maximum life span has been extended.
More recent studies have determined that modifications of the CR paradigm, including decreased restriction of caloric intake (i.e., more food permitted), increased time between meals rather than meal-skipping (independently of total calories), and "intermittent fasting" (alternating daily eating schedule), can also produce many of the salutary effects of the standard CR diet. And such modifications can also be found in the range of ascetic dietary regimens.
Although the mechanisms responsible for the life span extending and health enhancing effects of CR remain a topic of intensive investigation, much research points to the importance of anti-inflammatory and antioxidant (decreased radical oxygen species [ROS] generation and/or increased activation of endogenous free radical scavenging) mechanisms.
Furthermore, more recent research has shown that CR can enhance regenerative stem cell activation in several tissues, although it also possesses significant and robust anticancer properties as well, and both regenerative and oncostatic properties have an obvious significance for health enhancement and life span extension.
In this regard, CR has been found to retard the age related decline in melatonin and DHEA, both of which possess anti-inflammatory, antioxidant, and regenerative properties.