According to the World Health Organization, as many as 17 million people worldwide die each year from cardiovascular disease (CVD),¹ and it continues to be the leading cause of death in the United States.²  Stress, particularly psychosocial stress (caused by the social environment), is one of the major contributing factors of hypertension and CVD.  Acute stress is not as damaging as chronic stress, because the latter can overwhelm the body with a prolonged imbalance between an overactive sympathetic nervous system (associated with the “fight or flight” response) and an under-active parasympathetic nervous system (associated with rest, repair, and digestion)³: this is incredibly taxing both mentally and physically, as the body does not have sufficient opportunity to rejuvenate. 

Allostatic load, or the wear and tear on the body due to chronic stress, leads to declines in cognitive (i.e., mental) and physical functioning, and increases the likelihood of CVD.² Social and emotional factors (like hostility, anger, depression, socioeconomic issues and social isolation)^4,5 lead to increased stress, which in turn result in CVD risk factors (like obesity, elevated blood pressure, and high cholesterol).²  Evidence suggests that many diseases are caused by stress and the unhealthy lifestyle habits associated with it,⁶ like smoking, malnutrition and physical inactivity.²  Because psychosocial stress has been so heavily implicated in illness, including the recurrence and progression of cancer,⁷ there is a growing interest in psychosocial strategies,² like meditation, that are geared toward prevention.

Research seems to indicate that meditation is an effective method of stress management: it increases a sense of control and decreases anxiety.⁸  It appears that many of the benefits of meditation are because of its ability to reduce stress and thus restore health.²  In a study of a stress reduction program based on mindfulness meditation,⁷ subjects experienced an overall reduction in total mood disturbance (as measured by POMS: Profile of Mood States) of 65% compared to a 12% reduction in wait-list controls (i.e., subjects who were assigned to a wait-list and did not receive any training).  Vigour appeared to increase, while measures of anxiety, depression, and confusion decreased.⁷

As chronic stress overworks the sympathetic nervous system, it is likely that strategies favouring the parasympathetic nervous system (PNS) would be effective in reversing or limiting the effects of stress, and thus reducing the likelihood of CVD and promoting overall health.⁷  Meditation seems to encourage PNS activation, preventing maladaptive lifestyle choices (like substance abuse and poor diet)⁹: studies have shown that meditators are more relaxed, exhibiting reduced heart rate, respiratory rate and blood pressure.^9-13  Indeed, in a group of 127 subjects with mild hypertension, meditation was found to be twice as effective as a Progressive Muscle Relaxation program in reducing both systolic and diastolic blood pressure.⁹  Even among people with normal blood pressure, meditators had 20 mm Hg lower systolic blood pressure¹³ and 9 mm Hg lower diastolic blood pressure¹² than population norms and control subjects, respectively: these differences were independent of diet and exercise patterns. 

Meditation is correlated with an increase in β-endorphins, which reduce fear and pain, while producing sensations of joy and euphoria.¹⁰  It is also effective in reducing carotid atherosclerosis¹⁴ (i.e., the clogging, narrowing and hardening of arteries).  Smoking and alcohol abuse are major risk factors for CVD: meditation was found to be more effective in controlling and eliminating these habits than cessation counselling, pharmacological treatments, education programs, relaxation training, hypnosis or acupuncture.¹⁵  Angina patients, after being trained in Transcendental Meditation, improved duration of exercise by 14.7% (compared to 1.6% in controls) and maximal workload by 11.7% (compared to a reduction of 0.1% in controls), suggesting that meditation is effective in reducing exercise-induced ischemia¹¹ (i.e., inadequate flow of oxygenated blood).  According to Blue Cross/Blue Shield records, meditation practitioners with more than 6 months experience had 87% fewer hospital admissions related to heart and blood vessel diseases than non-meditators¹⁶; pregnancy-related admissions were essentially the same between the two groups, suggesting no difference in access to conventional care.¹⁶

Meditation is unique in that it provides the benefits of rest, and somewhat paradoxically, facilitates alertness at the same time.^17,18  In this way, it is not exactly the same as eyes-closed relaxation or mindfulness training.  This “restful awareness” allows for rejuvenation and insight, and provides “a means of monitoring and regulating [one’s] arousal.”⁷  For example, in situations that normally elicit an intense emotional reaction, the practitioner can choose to stay calm.  With continued practice, significant health benefits can be had, but it seems that those who practice meditation less than three times a week receive little or no benefit¹⁹: it is for this reason that most programs suggest a once or twice daily regimen.  This healthful practice not only alleviates physical symptoms, but also emotional ones as well: a Vietnam War veteran who suffered from post-traumatic stress disorder (i.e., “shell shock”), after learning a meditation technique, said, “I feel after I meditate that I no longer have the same intensity of tension, rage, and guilt inside – it’s as if a huge burden has been lifted.”¹⁷

References

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2. Walton KG, Schneider RH, Salerno JW, Nidich SI. Psychosocial stress and cardiovascular disease. Part 3: Clinical and policy implications of research on the transcendental meditation program. Behav Med. 2005 Winter; 30(4): 173-83.
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