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Chapter 18 Yoga for Cardiovascular Disease Prevention: Science behind the Art ASHA MOORTHY • JAIN T. KALLARAKKAL

(sensory withdrawal), dharana (concentration), dhy-ana (mediation) and samadhi (integration). The tra-ditional yogic practices are focused on development and unifi cation of both physical and spiritual as-pects. The modern yogic styles comprise mainly three aspects: physical postures (asana), breathing exercises (pranayama) and meditation (dhyana).

YOGA AND THE CARDIOVASCULAR SYSTEM

Yoga has shown to positively affect cardiovascular (CV) parameters. The effects of yoga on the CV sys-tem are thought to be mediated through neurologi-cal pathways such as the hypothalamic–pituitary–adrenal (HPA)/sympathoadrenal medullary (SAM) axes and the autonomic nervous system (ANS). The physical postures or asanas act through the neural networks such as the default mode network (DMN) 2 . The increased muscle activity and changes as seen in the CV and respiratory systems while performing the various asanas and pranayama are thought to be due to an increase in nitric oxide levels and an-tioxidant capacity in the blood vessels. This leads to changes in the endothelial function and arterial wall stiffness levels, thereby leading to blood pres-sure lowering with regular practice of yoga. A sig-nifi cant reduction in heart rate and blood pressure 3 , improved lipid profi le (total cholesterol, LDL, tri-glycerides) and reduction of body fat and BMI have also been reported with the practice of yoga.

STRESS, ANXIETY AND DEPRESSION

There has been a signifi cant accumulation of evidence highlighting the interrelated effects of negative affective states such as stress, anxiety and depression on CHD. There is evidence to support

INTRODUCTION

Coronary heart disease (CHD) is a leading cause of mortality and morbidity worldwide. There have been many advances in the management option for these conditions and while primary prevention is still considered an important aspect in reducing its prevalence, the management and secondary pre-vention have become priority considerations for the treating physicians. The current lifestyle mea-sures including high-stress levels, unhealthy dietary patterns and an increasingly ageing population re-quire interventions at all levels of prevention and management of CHD.

Currently the focus is on cardiac rehabilitation (CR) programmes which combine patient educa-tion, exercise (strength and aerobic) and stress man-agement with the aim to reduce the risk factors and improve functional capacity of individuals, thereby to reduce mortality associated with the condition. This can reduce CHD mortality by 20%–25% along-side their widespread acceptance and adoption into numerous national and professional management guidelines 1 .

YOGA

Practicing yoga regularly has been to shown to im-prove the physical and mental well-being by vari-ous physical and mental techniques. Yoga has its roots in the ancient traditions of the early civiliza-tions of the central Asian regions.

Yoga originated almost 5000 years ago and is heavily infl uenced by yogic sutras from 200 BCE. The yoga practice is defi ned and standardized into ‘eight limbs’ or key facets including yamas (obser-vance), niyamas (self-discipline), asana (physical postures), pranayama (breath regulation), pratyahara

142 SECTION II — Preventive Cardiology

that application of yoga in healthy, psychosocially affected and various pathological populations sig-nifi cantly reduces stress, anxiety and depression ( Fig. 18-1 ).

YOGA AND CHD RISK FACTORS

Hypertension : Nonpharmacological measures such a lowering the sodium intake have been shown to reduce the blood pressure by about 5–7 mm Hg (systolic)/ 2.7 mm Hg (diastolic) in hypertensive subjects. Moderately intense exercise at 40%–60% of maximum oxygen consumption (brisk walk for 30–45 min, 4–5 days/week) is also known to lower the blood pressure in some individuals. A random-ized controlled trial to estimate the effects of regu-lar yogic practice for 1 h/day even for a short pe-riod of time 11 weeks) showed it to be as effective as medical therapy in controlling blood pressure in hypertensive subjects 4 .

Impaired barorefl ex sensitivity is a known cause for essential hypertension. Yoga practice has been shown to restore barorefl ex sensitivity and thus is responsible for the benefi cial effects as seen in these patients. Head-up or head-down tilt asanas are found to be particularly benefi cial in these patients 5 .

Obesity and lipid profi le : A randomized controlled study was conducted for 1 year to assess the effects of yoga on body weight and body density and found very positive outcomes 6 . Signifi cant reduc-tions in body mass index, total serum and LDL cholesterol and fi brinogen in those who had ele-vated levels have also been shown with regular practice of yoga. The improved serum lipid pro-fi les were seen in patients with known ischaemic heart disease as well as in healthy subjects 7 .

Diabetes mellitus: Yoga has been shown to be benefi cial adjuvant for diabetic patients. In a group of diabetics who practiced yoga regularly, there was a signifi cant reduction in the fre-quency of hyperglycaemia and a decrease in the need for oral hypoglycaemics to maintain ade-quate blood sugar control 8 .

YOGA IN CHD PATIENTS

A reduction in the angina episodes per week were reported with regular practice of yoga exercises for a period of 1 year in a randomized controlled study with angiographically proven coronary artery disease patients. The study also showed an improvement in the exercise capacity and decrease in body weight in these patients. There were signifi cant reductions in

Cerebral cortex

Default modenetwork

Hypothalamus

Autonomicnervous system

Adrenal medulla

Catecholamines

Pro-inflammatorycytokines

Cardiovascular and metabolic variables:heart rate, blood pressure

heart rate variabilityendothelial function

lipids, body mass index

Negative affectivestates

Negativebehaviours

Pituitary

Corticotropin releasinghormone

Central mechanismAdrenocorticotropichormone

Cortisol

Adrenal cortex Hypothalamic-pituitaryadrenal axis

Sympatho-adrenalmedullary axis

Figure 18-1. Potential central and neuroendocrine pathways affected by yogic practice.

143Chapter 18 — Yoga for Cardiovascular Disease Prevention: Science behind the Art

serum cholesterol levels (total cholesterol, LDL cho-lesterol and triglyceride levels) as compared with control groups. The need for revascularization proce-dures was also reduced in the yoga group. Follow-up angiography at 1 year showed signifi cant lesion re-gression when compared to the control group (20% vs. 2%). Also, fewer lesions showed further progres-sion (5% vs. 37%) in the yoga group when compared with the control group 9 .

POST–MYOCARDIAL INFARCTION

Yoga practice combined with traditional pharma-cotherapy and physiotherapy has shown to be benefi cial in the recovery process following myo-cardial infarction. It has contributed to sleep, ap-petite and general well-being. Subjects who prac-ticed pranayama or controlled yogic breathing achieved higher work rates with reduced oxygen consumption per unit work. Their blood lactate levels were also signifi cantly low at rest 10 .

Yoga has the ability to control the sympathetic overdrive thus mimicking beta blockade. The breathing techniques (pranayams) have been shown to ameliorate the chronic hypoxia induced by chronic heart failure. These exercises train the respi-ratory muscles and can also improve dyspnoea and exercise capacity.

RISKS INVOLVED IN PRACTICING YOGA

Yoga is a safe form of exercise, especially when prac-ticed under the guidance and supervision of a qualifi ed trainer.

CONCLUSION

Considering the scientifi c evidence discussed, yoga can be benefi cial in the primary and secondary prevention of CV disease, and it can play a primary or a complementary role. Benefi cial effects of yoga have been demonstrated in total antioxidant sta-tus, NYHA functional class and angina episodes, ST

REFERENCES

1. Taylor, G. H., Wilson, S. L., & Sharp, J. ( 2011 ) Medical , psychological, and sociodemographic factors associated with adherence to cardiac rehabilitation programs: A systematic review. Journal of Cardiovascular Nursing , 26 , 202 – 209 .

2. Gard, T., Noggle, J. J., Park, C. L., Vago, D. R., & Wilson, A. ( 2014 ) Potential self-regulatory mechanisms of yoga for psychological health . Frontiers in Human Neurosci-ence , 8 , 770 .

3. Chauvet-Gélinier, J. C., Trojak, B., Vergès-Patois, B., Cottin, Y., & Bonin, B. ( 2013 ) Review on depression and coronary heart disease . Archives of Cardiovascular Diseases , 106 , 103 – 110 .

4. Murugesan, R., Govindarajalu, N., & Bera, T. K. ( 2000 ). Effect of selected yogic practices on the management of hypertension . Indian Journal of Physiology and Pharma-cology , 44 , 207 – 210 .

5. Jayasinghe, S. R. ( 2004 ). Yoga in cardiac health (a re-view) . European Journal of Cardiovascular Prevention and Rehabilitation , 11 , 369 – 375 .

6. Bera, T. K., & Rajapurkar, M. V. ( 1993 ). Body composi-tion, cardiovascular endurance and anaerobis power of yogic practitioner . Indian Journal of Physiology and Pharmacology , 37 , 225 – 228 .

7. Mahajan, A. S., Reddy, K. S., & Sachdeva, U. ( 1999 ). Lipid profi le of coronary risk subjects following yogic lifestyle intervention . Indian Heart Journal , 51 , 37 – 40 .

8. Jain, S. C., Uppal, A., Bhatnagar, S. O., & Talukdar, B. ( 1993 ). A study of response pattern of non-insulin de-pendent diabetics to yoga therapy . Diabetes Research and Clinical Practice , 19 , 69 – 74 .

9. Manchanda, S. C., Narang, R., Reddy, K. S., Sachdeva, U., Prabhakaran, D., Dharmanand, S., et al . ( 2000 ). Retarda-tion of coronary atherosclerosis with yoga lifestyle inter-vention . Journal of the Association of Physicians of India , 48 , 687 – 694 .

10. Raju, P. S., Madhavi, S., Prasad, K. V., Reddy, M. V., Reddy, M. E., Sahay, B. K., et al . ( 1994 ). Comparison of effects of yoga and physical exercise in athletes . Indian Journal of Medical Research , 100 , 81 – 86 .

segment depression and exercise duration. To con-clude, yoga in CHD may prove to be an invaluable adjunctive component to existing cardiac rehabili-tative interventions.