New Delhi, Dec. 16: Yoga may protect people from cardiovascular diseases by lowering their associated risk factors, a study by researchers at Harvard University and the Netherlands has suggested, bolstering evidence for what some already practice in India.
The new study, a meta-analysis of 32 earlier studies that had explored the effects of yoga on cardiovascular and metabolic health, has found that yoga can lead to reductions in body weight, blood pressure, cholesterol, triglycerides and heart rate.
The researchers also observed through a subgroup of the studies they analysed that the effects of practising yoga asanas on the risk factors was as good as the effects of aerobic exercise. Their findings were published yesterday in the European Journal of Preventive Cardiology.
“We can say with confidence that the evidence for the benefits of yoga is promising,” Myriam Hunink, a clinical epidemiologist at Erasmus University in the Netherlands who led the meta-analysis, told The Telegraph over telephone. “When we quantitatively pool the results from multiple studies, the power of the results increases — this increases the confidence in the findings,” Hunink said.
Yoga specialists in India said the results are not surprising but add evidence to a reservoir of scientific literature that has accumulated over the past two decades through studies by several research groups in India.
“We are already prescribing yoga to patients with cardiovascular diseases,” said Nagarathna Raghuram, a physician and dean of the division of yoga and life sciences at the Swami Vivekananda Yoga Anusandhana Samsthana (SVYASA) University, Bangalore, that also runs a hospital.
The study by Hunink and her colleagues found that several risk factors for cardiovascular diseases improved more in those practising yoga than in those not practising any exercise, but yoga had effects comparable to those from exercise.
They observed that the practice of yoga asanas on average reduced the body weight by 2.3kg, blood pressure by 4.9 mmHg, cholesterol by 18 mg/dl, triglycerides by 29 mg/dl and heart rate improved by 5.27 beats per minute.
The detailed physiological mechanisms to explain the effects remain unclear. “But the comparable effects of yoga and exercise tells us that something similar to what aerobic exercise also happens with yoga,” Hunink said.
Doctors who have studied the physiological effects of yoga believe mechanisms involve stress reduction. “Yoga acts through the body and mind management,” Nagarathna told this newspaper. “The observed reductions in risk factors may be regulated through lowered stress.”
Nagarathna and her colleagues have shown through a study in Bangalore that yoga can significantly improve the quality of life of patients with cardiovascular disease who have undergone cardiac surgery.
The SVYASA study, conducted in partnership with doctors at the Narayana Hrudayalaya Institute of Cardiac Sciences and just published in the Indian Heart Journal, has found that patients who practised a combination of yogic breathing, meditation and relaxation after surgery had better levels of heart pumping efficiency, body weight and cholesterol than patients who did not adopt yoga.
Since the mid-1990s, groups of doctors at the All India Institute of Medical Sciences, New Delhi, and other institutions in Mumbai and Pondicherry have documented the beneficial effects of yoga on cardiovascular diseases.