A number of studies on meditation have demonstrated effects that are consistent with a lengthening of both the (mean) life span and the “health span.” Recently, a large-scale epidemiologic 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.
More recently, a study on the benefits of meditation looked at the components of the metabolic syndrome in patients with coronary heart disease, found that four months of practice led to significant improvements in fasting glucose levels, insulin levels, insulin sensitivity, systolic blood pressure, and heart rate variability; although utilizing a patient population, these results are obviously suggestive for aging in general, particularly in light of the fact that blood pressure, glucose and insulin levels, and insulin sensitivity are generally regarded as biomarkers of aging. Other studies on TM that have attempted to evaluate practitioners against controls with respect to putative agingrelated 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. Still 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.
Since the early “classic” studies on natural remedies for anxiety and metabolic rate in meditators to the present, the preponderance of evidence suggests that forms of meditation intended to reduce overall systemic arousal, or in other terminology to elicit the relaxation response, do in fact lower metabolic rate. Furthermore, of particular interest in the present context is the evidence for profound reductions in metabolism demonstrated by long-termvirtuoso practitioners of meditation (and yoga). This body of research and analysis, undertaken by scientists affiliated with the Scripps Institute, Stanford, Harvard, and Rockefeller Universities, and other institutions, discovered that such putative, long-term virtuoso practitioners, could lower their metabolic rate by as much as 40– 64%, which is actually within the range of hibernating animals!
In fact, other evidence suggests that such practitioners may in fact enter states of “quiescence” 18 that are strikingly similar to hibernation states entered into by animals such as the bear. Genomic analysis suggests that genes common to hibernators are found generally in mammals, including nonhuman and human primates, and include genes regulating enzymes that are critical for the induction, maintenance, and survival of hibernation states. Primates that hibernate have recently been discovered, and the “hibernation induction trigger” (HIT) isolated from the plasma of typical hibernators when injected into primates induces an apparently orchestrated suite of physiological and behavioral responses common to most hibernators (hypophagia, hypothermia, hypometabolism, etc.). In the field of physical/physiological anthropology, researchers discovered that some peoples, in particular Native Australians (“Aboriginals”), enter into periods of torpor on a near daily basis, while studies from earlier in the century found seasonal hibernationlike states in large groups of “peasants” existing in prolonged cold under prolonged conditions of food deprivation. Humans are often successfully able to physiologically tolerate extremes in temperature, metabolism, and related physiological functions (e.g., hydration levels), according to a wide, if disparate, range of data from studies of medical hypothermia, cold water near-drowning,wheelwell jetliner stowaway survivors, and other survivors of accidents (skiing, etc.) under extremely cold ambient conditions.
Focused studies on particular virtuoso yoga/meditation practitioners have found a range of phenomena which are, remarkably, also common to hibernators: reductions in respiratory rate to as low as 1/min, which at times may alternate with periodic apneas (i.e., “intermittent respiratory pattern”), followed by hyperventilation during arousal; cardiac activity in which initial tachycardia preceding entry into hibernation is followed by prolonged bradycardia; reductions in body temperature (from 3 to 132 F, in the range of some hibernators, including bears) and metabolism (e.g., from 4065%); as well as other physiological and biochemical phenomena (e.g., decreased plasma creatinine and urea, reduced kidney function, others); whereas arousal from such states in hibernating animals and the yogis examined may actually involve strikingly similar patterns of tachycardia, violent shivering, hyperventilation, and emergence from an obvious stuporous mental state.
In particular, the reduced metabolic rate associated with “quiescent states” such as hibernation, torpor, estivation, and diapause, appears to be associated with a slowed rate of aging, according to recent review of the data published by Stuart and Brown and Storey and Storey. In lower model organisms such as Caenorhabditis elegans, animals entering the hypometabolic dauer stage of diapause live 6 months, as compared to control animals not entering this state, which typically live for a maximum of 3 weeks. In higher organisms, such as the bat, regular daily torpor results in a 50% increase in life span. Furthermore, Lyman at Harvard found a similar magnitude of life span increase in Turkish hamsters allowed to hibernate, in comparison to those not allowed to, which latter group exhibited similar life spans as non-hibernating Turkish hamsters under wild conditions.
