In a study reported in the June 12 issue of the Archives of Internal Medicine, researchers report that the practice of transcendental meditation can significantly decrease insulin resistance, lower blood pressure and decrease heart rate variability.
"It's possible to use the mind-body connection to tap into the body's own inner intelligence to bring about changes in physiology to reverse the risk of diabetes and heart disease," said Dr. Robert Schneider, director of the Institute for Natural Medicine and Prevention at the Maharishi University of Management in Maharishi Vedic City, Iowa. Schneider is also a co-author of the book Total Heart Health.
Of the reduction in insulin resistance, Schneider noted, "a reduction like this would make a drug company a lot of money. The only other things that could bring about such a reduction are intensive exercise or a large weight loss."
Insulin resistance is one of the key players in metabolic syndrome, a group of cardiovascular risk factors that occur simultaneously, thus increasing the risk of heart disease. When the body doesn't properly use insulin, excess glucose remains in the blood, which affects many of the body's functions. Excess glucose causes a rise in triglycerides and other blood fats. It also impairs kidney function, which can lead to high blood pressure.
In collaboration with researchers from the University of Southern California Keck School of Medicine and Cedars-Sinai Medical Center, Schneider and his colleagues recruited 103 people who had already been diagnosed with heart disease to study the effects of transcendental meditation on heart disease risk factors. Eighty-four of these recruits completed the 16 weeks of the study.
The average age of the study participants was about 67, and slightly more than 40 percent were male. The average body mass index was 28, which means the average study volunteer was overweight, but not obese. About one-third had a history of high blood pressure, and 9 percent had diabetes.
The study participants were randomized into one of two groups for the study. One group received training in and practiced transcendental meditation twice a day for 20 minutes at a time for four months, while the other group received health education about heart disease.
Schneider explained that transcendental meditation involves sitting quietly while your mind settles into a quieter and quieter state until you're not thinking at all, literally "transcending the thinking process," he said.
The researchers found that systolic blood pressure -- that's the top number -- dropped by more than 3 points in the meditation group and went up more than 2 points in the health education group during the study period.
Meditation also had positive effects on heart rate variability, another measure of heart health. A decrease in heart rate variability is a negative sign, and those in the health education group had a decrease in heart rate variability during the study period, while those in the meditation group saw a slight increase in heart rate variability.
The most significant change, according to Schneider, was seen in insulin resistance. In a measurement that compares fasting blood glucose and insulin levels, the health education group went up 0.52 while the meditation group went down by 0.75 -- a "significant" change, according to the authors.
"This is important. It's not earthshaking news, but [these researchers] have extended the information on transcendental meditation to include insulin resistance and metabolic syndrome," said Dr. Louis Teichholz, medical director of cardiology and complementary medicine at Hackensack University Medical Center.
Teichholz said these benefits probably aren't limited to transcendental meditation, but likely include other forms of relaxation, such as yoga, tai chi, guided imagery, biofeedback and even exercise. Schneider, however, pointed out that right now, transcendental meditation is the only method that's been proven in randomized clinical trials.
He said meditation and other forms of relaxation have beneficial effects because they activate the parasympathetic part of the autonomic nervous system, which helps calm down the body's fight-or-flight response, which is triggered by the body's sympathetic nervous system. When the sympathetic system is activated by stress, it causes the body to release hormones, and those hormones can help make the body resistant to insulin. However, when the parasympathetic system is activated, the body's cells become more responsive to insulin, Teichholz explained.
"You can't always change the stress," he said. "But it's not the stress that matters, but how you respond to it. If you can respond in a different way, you can negate some of the negative effects of stress."