Meditation, Stress, and Aging

Meditation, yoga, tai chi and other practices often are mentioned in passing as being good for health. However, it is surprising how little medical research has been devoted to testing such claims. Perhaps equally surprising is that until recently little work had been undertaken to quantify the impact of stress on aging. Of course, people often talk about reducing stress and note that too much stress is not good for us, but how much is too much and what, exactly, is the impact on the length of life? It took the interest of a Nobel Prize Winner finally to direct research at medical schools towards these questions. A paper by Epel and Blackburn on the impact of stress on the length of telomeres, a direct cellular measure of successful aging, only appeared in the Proceedings of the National Academy of Sciences in December 2004.¹ More than a decade later, meditation has begun to be accepted as a low cost /no cost approach to health benefits.

Stress and Adrenal Fatigue

In medical circles, two syndromes often are discussed with regard to what laymen consider to be the consequences of stress. The first is adrenal insufficiency. Adrenal insufficiency is a condition in which the adrenal glands do not produce adequate amounts of steroid hormones, primarily cortisol; it also may include impaired production of aldosterone (a mineralocorticoid), which regulates sodium conservation, potassium secretion, and water retention. Craving for salt or salty foods due to the urinary losses of sodium is common. Adrenal insufficiency is a medical condition that requires intervention beyond dietary supplements.

Adrenal fatigue occupies a bit of a nether world in many medical circles, meaning that allopathic medicine is not quite sure that it is real. According to the Mayo Clinic, adrenal fatigue is a term often applied to a collection of nonspecific symptoms, such as body aches, fatigue, nervousness, sleep disturbances and digestive problems. However, it also is used as a catch-all for the exhaustion caused by placing demands upon the body that are beyond its normal recovery capacity. Very important in this picture is cortisol, a hormone manufactured in the adrenals, but also exhibits a metabolism that is regulated strongly in various peripheral tissues, such as in fat stores.

The counter-regulatory or "stress" hormone cortisol plays crucial everyday roles in the regulation of blood sugar levels, inflammation and the circadian rhythm. Cortisol should be relatively low late in the day as we unwind and prepare for sleep and should rise quite significantly starting an hour or two before waking. The circadian pattern of cortisol release generally is considerably more important than is its total 24-hour level.

Acute demands outside the normal range and chronic stress alter this picture. Recurrent increases in stress levels, both from psychological and physiological sources, can result in excess cortisol production or alterations in cortisol release timing leading to a disrupted homeostasis and directly affecting the hypothalamic-pituitary-adrenal (HPA) axis, the nervous system, and an array of other body systems.

Immediate responses to stress
Typical acute phase reactions to stress are increases in heart and respiratory rates, elevations in blood pressure and blood sugar, and a general increase in cellular metabolism.

Post-stress reactions
Those in good health, especially younger individuals, quickly recovery equilibrium. However, stress in excess of immediate recovery capacity can lead to bouts of hyperglycemia, fatigue, insomnia, irritability, anxiety, etc.

Poor recovery from stress
Chronic stress disrupts the normal equilibrium of the body. Chronic elevations of cortisol and the neurotransmitters epinephrine and norepinephrine initially cause people to feel energetic, yet unable to rest. Indeed, there is increasing dysregulation of an array of hormonal systems, including growth hormone, glucocorticoids, adrenocorticotropic hormone (ACTH), mineral corticoids, angiotensin, and others. Ultimately a number of vicious cycles can be set in motion. These include set points involving mineral corticoids and insulin. One example of this is a cycle involving blood sugar, insulin and cortisol:

chronic ↑ blood sugar => ↑ insulin + ↑ leptin => insulin resistance + leptin resistance => ↑ cortisol => ↑ blood sugar

Depending on the individual's starting constitution and habits, this can lead to elevations of blood sugar and lipids, water retention, mood swings, a loss of lean tissue followed by a gain in fat tissue, generalized fatigue and other symptoms.

The goal of any program aimed at controlling stress and reducing adrenal fatigue is to promote adaptation. One classic way of thinking about this issue is to consider the medical concept of allostasis, the process of achieving stability, or homeostasis, through physiological or behavioral changes. This can be carried out by means of alterations in HPA axis hormones, the autonomic nervous system, cytokines, or a number of other systems, and is generally adaptive in the short term. This adaptation calls upon mediators such as adrenalin, cortisol and other chemical messengers with the obvious corollary of increasing demands on precursor substrates and the production of downstream metabolites.

Repeated episodes of allostasis increase allostatic load. This means that repeated episodes of stress increase the demands that are placed on the body. Even the body's attempts at rebalancing can lead to cumulative damaging effects. The burden of the level of responses required either repeatedly or chronically itself becomes an insult (stressor) in its own right.^2,3

Meditation, Stress and Telomeres
The pioneering work of Epel and Blackburn linked perceived stress to shorter telomeres in healthy women as well as in Alzheimerfs caregivers, victims of domestic abuse and earlylife trauma, and people with major depression and posttraumatic stress disorder. Telomeres are a repeating DNA (deoxyribonucleic acid) sequence that "caps" or shields the ends of the chromosomes each time that cells divide and the DNA is copied. With successive cell divisions, the protective caps wear down. Blackburn received a Nobel Prize for discovering an enzyme called telomerase that can protect and rebuild telomeres. This enzyme slows the slide towards telomeres becoming too short to protect the chromosomes and leading to a loss of the ability of cells to divide. The length of telomeres thus is one measure of how many cycles the cells have left, a measure of aging. The key finding regarding stress and aging is that stress and our ability to cope with stress strongly affect telomere length. Subsequent work in other labs revealed that the stress hormone cortisol reduces the activity of telomerase. Oxidative stress and inflammation—the physiological fallout of stress—appear to erode telomeres directly.^4,5

There are various ways of attempting to control stress its negative effects, including exercise, social support groups, eating advice, and so forth. One of the most successful in trials is meditation. As reported in an excellent 2104 BBC review,⁶

In one ambitious project, Blackburn and her colleagues sent participants to meditate at the Shambhala mountain retreat in northern Colorado. Those who completed a three-month-long course had 30 percent higher levels of telomerase than a similar group on a waiting list. A pilot study of dementia caregivers, carried out with UCLA's Irwin and published in 2013, found that volunteers who did an ancient chanting meditation called Kirtan Kriya, 12 minutes a day for eight weeks, had significantly higher telomerase activity than a control group who listened to relaxing music. And a collaboration with UCSF physician and self-help guru Dean Ornish, also published in 2013, found that men with low-risk prostate cancer who undertook comprehensive lifestyle changes, including meditation, kept their telomerase activity higher than similar men in a control group and had slightly longer telomeres after five years.

Western style research thus increasingly is validating meditation as a tool for combatting known markers for aging. The next issue is whether meditation improves individual conditions, such as high blood pressure and high blood sugar.

Meditation and Specific Conditions
Telomere length and the production of telomerase to regenerate telomeres are indirect measurements of health. Impacts on these markers can suggest anti-aging benefits, but true clinical findings involve endpoints, not markers, i.e., were subjects followed long enough to demonstrate an actual increase in longevity? With long-lived animals such as human beings, this type of follow-through is difficult. However, meditation has been tested in regard to specific medical conditions, including blood pressure, blood sugar and mental aging. Results have been positive in all three.

Blood Pressure
Although statistical reviews typically have found that clinically meaningful changes in health related to blood pressure usually take place only when systolic blood pressure (SBP, the upper figure) exceeds 140 and diastolic blood pressure (DBP) exceeds 90, in recent years increasing attention has been paid to the category of prehypertension. Nearly 60 million Americans have blood pressure (BP) in the prehypertensive range (SBP of 120– 139 and/or DBP of 80–89). These numbers do not yet warrant medication, yet may signal that changes in diet, exercise and other habits should be undertaken to prevent the emergence of the clinical condition that does require treatment.

Mindfulness-based stress reduction (MBSR) is a change in habits that has been tested under controlled conditions. In a trial published in 2013, it involved body scanning exercises, sitting meditation and yoga exercises performed in eight supervised group sessions totaling 2½ hours per week. Subjects also were encouraged to practice at home. The trial examined 56 men and women averaging 50.3 years of age with BP in the prehypertensive range randomized to eight weeks of either MBSR or active control conditioning consisting of progressive muscle relaxation training (PMR) (the control arm).⁷

Patients in the MBSR group exhibited significant reductions in blood pressure measurements; systolic blood pressure decreased by an average of 4.8 millimeters of mercury (mm Hg) compared to 0.7 mm Hg with the control group, which did not receive the mindfulness intervention. Diastolic blood pressure also was lower in the mindfulness-based intervention group with a reduction of 1.9 mm Hg compared to an increase of 1.2 mm Hg in the control group.

Blood Sugar
As is true of blood pressure, in free-living populations meditation and other mind-body practices long have been associated with better body mass index and blood sugar regulation.⁸ Nevertheless, without prospective clinical trials, such benefits cannot be definitively claimed to be due to any given factor. Over the last handful of years, studies have gone some way towards remedying this issue.

In 2015, the Endocrine Society presented information on the effects of MBSR on fasting blood glucose in overweight and obese women. The NIH National Center for Complementary and Alternative Medicine (NCCAM) and the NIH National Center for Research Resources and the National Center for Advancing Translational Sciences funded the study.⁹ A pilot randomized controlled trial of 86 overweight or obese women (similar in age and body mass index) tracked eight weeks of either MBSR or health education control (HEC) with tests of fasting blood work and completed questionnaires at baseline, eight weeks and then at 16 weeks. The MBSR group's mindfulness scores significantly increased and its perceived stress scores significantly decreased compared to the HEC group's scores. Fasting glucose dropped significantly and quality of life improved significantly in the MBSR group, but not in the HEC group. Other measures were similar between the two groups.

Results with the MBSR intervention were good with regard to blood sugar just as with blood pressure. A different form of meditation may be even more successful. Traditional Buddhist walking meditation in a 2016 trial improved not only fasting blood glucose and blood pressure, but also glycosylated hemoglobin (HbA1c, a measure of long term blood sugar control) and other factors above the results found with walking alone in diabetic test groups.¹⁰ Twenty-three type 2 diabetics were split into two groups that performed a 12-week exercise program that consisted of walking on the treadmill at an exercise intensity of 50–70 percent maximum heart rate for 30 min/session, 3 times/week. In the Buddhism-based walking meditation exercise (WM) training program, the participants performed walking on the treadmill while concentrating on foot stepping by voiced "Budd" and "Dha" with each footstep that contacted the floor to practice mindfulness while walking.

Both arms in this trial improved. After 12 weeks, maximal oxygen consumption increased and fasting blood glucose level decreased significantly in both groups. In contrast, walking meditation exceeded simple treadmill exercise in other areas. There were significant decreases in HbA1c and both systolic and diastolic blood pressure only in the WM group. Again, arterial stiffness was improved only in the WM group and blood cortisol levels were reduced only in the WM group.

Brain Aging
Another area, one that concerns all of us who are getting a bit older, is brain aging. Observational studies and a number of studies have indicated that meditation can exert a positive influence, yet the question of "how" remains poorly determined. Does it involve telomeres, inflammation, stress regulation, macroscopic brain anatomy or other mechanisms? Answers suitable to the Western allopathic medical model only now are beginning to be uncovered.

A review published in 2017 attempts to survey the relevant issues.¹¹ It judges that "preliminary evidence for possible age-defying effects of meditation mostly stems from cross-sectional studies and/or from using indirect markers associated with aging. In contrast, controlled longitudinal studies between meditation and diminished brain aging are still missing." Nevertheless, "[w]ithout a doubt, the accumulating scientific evidence is very encouraging, especially given that meditation is relatively easy to integrate in everyone's every-day life."

Conclusions
A philosophical person—a lover of wisdom—indulges his appetites neither too much nor too little, but just enough to lay them to sleep and prevent them from interfering with higher activities. He collects himself in meditation to pursue spiritual investigations, seeking and discovering unrealized realities of the past, present, and future. Through identifying with his Higher Self in meditation he avoids being the victim of fantastic and uncivilized vagaries and most effectively attains Truth.

Plato, Commonwealth 9, 571d¹²

We tend to think of meditation as an "Eastern" tradition, but, in fact, very similar practices existed in the ancient Greco-Roman world until the closure of the Platonic Academy in 529 AD by Justinian I. A major goal of meditation is to attain inner balance neither by indulging the passions nor by stifling them. Many different techniques exist. Overall, the goal of classic meditation exercises was and remains spiritual benefit. Modern research has discovered that even those not directly interested in religious or philosophical paths can obtain quite real and tangible benefits from meditative practices. These benefits include stress reduction, a balancing of blood pressure and blood sugar and, perhaps, greater longevity.

References:

1. Epel ES, Blackburn EH, Lin J, Dhabhar FS, Adler NE, Morrow JD, Cawthon RM. Accelerated telomere shortening in response to life stress. Proc Natl Acad Sci USA. 2004 Dec 7;101(49):17312–5.
2. McEwen BS, Seeman T. Protective and damaging effects of mediators of stress. Elaborating and testing the concepts of allostasis and allostatic load. Ann N Y Acad Sci. 1999;896:30–47.
3. McEwen BS. Central effects of stress hormones in health and disease: Understanding the protective and damaging effects of stress and stress mediators. Eur J Pharmacol. 2008 Apr 7;583(2–3):174–85.
4. Marchant J. Can Meditation Help Prevent the Effects of Aging? July 1, 2014. http://www.bbc.com/future/story/20140701-canmeditation- delay-ageing
5. Epel E, Daubenmier J, Moskowitz JT, Folkman S, Blackburn E. Can meditation slow rate of cellular aging? Cognitive stress, mindfulness, and telomeres. Ann N Y Acad Sci. 2009 Aug;1172:34–53.
6. Marchant (op. cit.)
7. Hughes JW, Fresco DM, Myerscough R, van Dulmen MH, Carlson LE, Josephson R. Randomized controlled trial of mindfulness-based stress reduction for prehypertension. Psychosom Med. 2013 Oct;75(8):721–8.
8. Younge JO, Leening MJ, Tiemeier H, Franco OH, Kiefte-de Jong J, Hofman A, Roos-Hesselink JW, Hunink MG. Association Between Mind-Body Practice and Cardiometabolic Risk Factors: The Rotterdam Study. Psychosom Med. 2015 Sep;77(7):775–83.
9. The Endocrine Society. "Stress reduction may reduce fasting glucose in overweight and obese women." ScienceDaily, 6 March 2015. www.sciencedaily.com/releases/2015/03/150306181815.htm
10. Gainey A, Himathongkam T, Tanaka H, Suksom D. Effects of Buddhist walking meditation on glycemic control and vascular function in patients with type 2 diabetes. Complement Ther Med. 2016 Jun;26:92–7.
11. Kurth F, Cherbuin N, Luders E. Promising Links between Meditation and Reduced (Brain) Aging: An Attempt to Bridge Some Gaps between the Alleged Fountain of Youth and the Youth of the Field. Front Psychol. 2017 May 30;8:860.
12. An admittedly idiosyncratic, yet helpful translation found at http://www.hermes-press.com/meditation0.htm

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