Yoga helps patients regain health after heart attacks faster to return to a normal life and reduces the risk of hospitalization and death, according to the world's largest yoga study in cardiac rehabilitation conducted in India and released on Sunday.
Research, funded by the Indian Medical Research Council and the Medical Research Council in the UK, suggested that daily sessions of breathing, exercise and relaxation are safe for patients and significantly improve their quality of life.
Doctors in 24 hospitals in India spent over three years tracking the health of almost 4,000 patients after heart attacks. Approximately half of the patients, with the standard prescription of drugs and diet, also joined a well-organized yoga program developed by scientists from India and Great Britain.
"We now have strong evidence to show that this affordable yoga regime is safe and beneficial to patients," said Dorairaj Prabhakaran, a cardiologist and vice president of the Public Health Foundation in India, New Delhi, who led the study. He announced the results at the American Heart Association scientific session in Chicago on Sunday.
Patients received instruction on the yoga program from trained instructors in their hospitals in 13 sessions spread over three months and audio-visual material to continue daily self-service sessions at home.
Doctors observed slightly lower percentages of hospitalization and death risk among patients who participated in 10 or more of the 13 planned training sessions.
"We believe that yoga helps reduce the number of cardiovascular events in those who have completed at least 75 percent of training sessions," says Ambuj Roy, a professor of cardiology at the All India Institute of Medical Sciences in New Delhi, a participating hospital.
Although AIIMS physicians began to study the physiological effects of yoga on the cardiovascular system over 20 years ago, researchers point out that such traditional practices are often seen with suspicion by mainstream medicine.
'This important clinical trial with the highest scientific standards underlines the potential role of traditional practices that play a complementary role in managing chronic diseases,' said Sanjay Kinra, head of epidemiology at the London School of Hygiene and Tropical Medicine and co-chairman of the study.
The American Society of Cardiology, after analyzing the available evidence, published a "scientific statement" in September 2017, saying that the potential benefits of meditation in patients with known coronary artery disease are in general "moderate and suggest but definitely not benefit".
"Our study increases the evidence – the results should prompt cardiologists to consider prescribing yoga as part of cardiac rehabilitation," said Bhishav Mohan, a professor of cardiology at Dayanand Medical College and Hospital in Ludhiana, where 700 patients joined the study.
Mohan points out that standard cardiac rehabilitation involves gradual exercises in which patients are asked to use the treadmill or carry weights under the supervision of trained medical personnel. "Such practices are too expensive for many households – our data suggest that yoga can be an alternative to such a rehabilitation," said Mohan.
Researchers are convinced that research results are particularly relevant in India, where the incidence of coronary heart disease has increased from 10 million in 1990 to 24 million people in 2016.
Although this study did not investigate the mechanisms by which yoga provides benefits, Mohan said independent research suggests physiological changes that have positive cardiovascular effects due to yoga practice.
"One of the well-established physiological effects is yoga, which involves lowering the levels of catecholamines, which are hormones produced by the adrenal glands," said Mohan. "Excessive catecholamines are harmful to the body."