Archive for the ‘Yoga Science Cardiovascular Disease’ Category

Research paper by Jayaram Gadham, Srikanth Sajja, V. Rooha. International Journal of Research in Medical Sciences. 2015;3(5):1061-1065. doi: 10.5455/2320-6012.ijrms20150506

In this 3-month randomized study, investigators examined the effects of a yoga intervention on weight, blood pressure, and lipid profile in 50 male patients. At the end of the study, they found a statistically significant decrease in systolic blood pressure (SBP), diastolic blood pressure (DBP) and body-mass index (BMI).

Study participants (age range, 35 to 55 years) exhibited one, two, or all three of the inclusion criteria: obesity, hypertension, and dyslipidemia. All were assigned to a daily, 1-hour yoga session at a local yoga center. The session consisted of 30 minutes of pranayama and 30 minutes of asana. 

Measurements of the study variables taken before and after the 3-month intervention showed a significant decreases in SBP (baseline mean, 135.6 ± 4.39 vs 125.18 ±9.29 at 3 mo), DBP (baseline mean, 88.86 ±3.51 vs 83.2 ±48 at 3 mo), and BMI (baseline mean, 27.040 ±2.03 vs 26.278±1.94 at 3 mo). Decreases in total cholesterol, very low-density lipoprotein cholesterol, and triglycerides were also observed, but were not statistically significant; there was also an observed but non-significant increase in high-density lipoprotein cholesterol.

“Yoga provides one of the best means of self-improvement and gaining full potential of one’s body, mind and soul,” investigators observed. “Yoga and certain asanas have beneficial effect on . . . cardiovascular risk factors like obesity, hypertension and dyslipidemia. Randomized controlled trials are needed to confirm and elucidate the effects of standardized yoga programs. There is a need to provide a better recognition of yoga by the health care community as a complement to conventional medical care.”

Summary by Louise Fecher

Research paper by Paula Chu, Rinske A. Gotnik, Gloria Y. Yeh, Sue J. Goldie, MG Myriam Hunink. European Journal of Preventive Cardiology. December 2014. [Epub ahead of print] doi: 10.1177/2047487314562741

In this study, the investigators examined data from 37 peer-reviewed, randomized, controlled trials that explored the potential effects of yoga on cardiovascular health. For meta-analysis, the investigators pooled (ie, combined) data from 32 of the 37 trials. Their conclusions, which were widely reported at the end of 2014 in the mainstream press (including Forbes.com) were that yoga may be beneficial to managing and improving risk factors associated with cardiovascular disease (CVD) and metabolic syndrome.

The total number of participants in all trials was 2768 (47% men, 53% women), with a mean age of 50 years. Of these, 1287 participants were randomized to a yoga intervention and 1461 were randomized to a control group. Study duration varied, ranging from 3 weeks to 52 weeks. Data were analyzed from the participants who completed the studies: 1094 in the yoga groups and 1301 in control groups.

Their conclusions . . . were that yoga may be beneficial to managing and improving risk factors associated with cardiovascular disease (CVD) and metabolic syndrome.

The yoga interventions used in the trials varied in style (from gentle to vigorous), frequency, and duration. Control groups varied as well and included conventional medical therapy, education, diet, and exercise. For analysis, the investigators divided the control groups into two subgroups–non-exercise and exercise–to determine the effectiveness of yoga in active vs nonactive controls.

When compared with non-exercise controls, yoga subjects showed significant improvement of risk factors for all primary outcomes: body mass index (BMI), systolic blood pressure (SBP), and low- and high-density lipoprotein cholesterol (LDL-C, HDL-C). Significant improvement was also seen in the yoga subjects in most secondary outcomes–body weight, diastolic blood pressure (DBP), total cholesterol (TC), triglycerides (TG), and heart rate–but not in fasting blood glucose (FBG) or glycosylated hemoglobin (HbA1c).

“This review demonstrates the potential of yoga to have an impact on concrete, physiological outcomes that represent some of the greatest health burdens today.”         -Chu et al, 2014

Furthermore, when yoga was used in addition to medication in patients with type 2 diabetes or coronary artery disease, significant improvement was found in body weight, BMI, blood pressure, lipid levels, FBG, HbA1c, and heart rate.

When yoga subjects were compared with aerobic exercise controls (including running and cycling), the investigators found no significant difference in the benefits provided by the two approaches for body weight, SBP, DBP, heart rate, BMI, LDL-C, HDL-C, TC, TG, and FBG. The authors suggested that the similar effectiveness of the two strategies may be due to comparable underlying working mechanisms, “with some possible physiological aerobic benefits occurring with yoga practice, and some stress-reducing, relaxation effect occurring with aerobic exercise.”

The investigators concluded that yoga may prove to be a cost-effective treatment and prevention strategy for CVD and metabolic syndrome. “This review demonstrates the potential of yoga to have an impact on concrete, physiological outcomes that represent some of the greatest health burdens today,” they wrote.

Summary by Louise Fecher

Research paper by Heather Mason, Matteo Vandoni, Giacomo deBarbieri, Erwan Codrons, Veena Ugargol, Luciano Bernardi. Evidence-Based Complementary and Alternative Medicine. 2013, Article ID 743504. doi:10.1155/2013/743504  

In this assessment, investigators observed the effects of ujjayi breath and slow breathing on cardiovascular and respiratory variables in yoga-naive subjects. They began with the premise, derived from previous research, that a reduced breathing rate (approximately 5-6 breaths per minute) increases cardiac-vagal baroreflex sensitivity (BRS, a measure of the heart’s capacity to regulate blood pressure in different situations), improves oxygen saturation, and lowers blood pressure. The investigators’ intent was to examine whether ujjayi breath offered additional positive effects to slow breathing alone.

Investigators recruited 17 healthy nonsmokers (8 male, 9 female; average age, 26 to 28 years) who had never practiced yoga. Participants received approximately 10 minutes of training in ujjayi breathing technique prior to testing. Participants were then connected to monitoring devices to measure cardiac and respiratory variables. The testing phase comprised 7 breathing conditions: 

• Spontaneous breathing (baseline)
• Fast breathing (15 breaths per minute, 2-second inspiration and expiration) without ujjayi
• Slow breathing (6 breaths per minute, 5-second inspiration and expiration) without ujjayi
• Slow breathing (6 breaths per minute, 5-second inspiration and expiration) with ujjayi on both inspiration and exhalation
• Slow breathing (6 breaths per minute, 5-second inspiration and expiration) with ujjayi on exhalation only
• Slow breathing (6 breaths per minute, 3-second inspiration and 7-second expiration) without ujjayi
• Slow breathing (6 breaths per minute, 3-second inspiration and 7-second expiration) with ujjayi on exhalation only

Data analysis showed that fast breathing reduced BRS, while all slow breathing conditions increased BRS vs spontaneous breathing. This increase was significant for all slow breathing conditions without ujjayi, and for slow breathing with ujjayi on exhalation alone, but was not significant for slow breathing with ujjayi on inspiration and exhalation. The authors suggested that the increased respiratory effort required to perform ujjayi, particularly for yogic breathing-naive subjects, might have caused the reduction of BRS benefit.

All of the breathing conditions significantly increased oxygen saturation vs baseline. When ujjayi was added to slow breathing, oxygen saturation increased further. With the exception of slow breathing with equal inspiration/expiration, all slow breathing conditions increased heart rate vs baseline. Overall, ujjayi breathing increased heart rate more than slow breathing alone. 

All of the breathing conditions significantly increased oxygen saturation vs baseline. When ujjayi was added to slow breathing, oxygen saturation increased further. 

All slow breathing conditions, with and without ujjayi, reduced blood pressure vs baseline. The greatest decrease in blood pressure was seen with slow breathing without ujjayi with equal inspiration/expiration.

Investigators concluded that while ujjayi breathing offered the maximum oxygen saturation of all observed breathing conditions, slow breathing with similar inspiration/expiration times appeared the most effective and simple way to increase BRS and oxygen saturation and lower blood pressure in yoga-naive subjects.

Summary by Louise Fecher

Research paper by Indla Devasena, Pandurang Narhare. International Journal of Biological & Medical Research. 2011;2(3):750-753.

In this 6-month study, investigators observed the effects of a daily yoga practice on heart rate and blood pressure in 50 healthy participants over the age of 40. Data analysis showed significant reduction in heart rate (HR) and highly significant reduction in diastolic blood pressure (DBP) and systolic blood pressure (SBP) after 6 months of yoga.

“Psychological stresses of our modern life precipitate various cardiovascular and other disorders by distorting basic neuroendocrine mechanism,” the authors wrote in the introduction to their article, adding that “[c]hronic exposure to psychosocial stimuli will result in the development of increase in blood pressure, coronary thrombosis and heart failure.”

The 50 participants (20 female, 30 male) had yoga experience prior to entering the study. They were trained for the study by a certified yoga teacher, and instructed to perform yoga for 1 hour daily, beginning at 6 am, for 6 months. The yoga protocol included a variety of asana (standing, sitting, prone, and supine poses) and pranayama. Each session concluded with meditation and savasana. 

Cardiovascular status of each participant was assessed after 2, 4, and 6 months of daily yoga practice. Data analysis showed that resting HR decreased significantly after 2 months of yoga. There was further reduction in HR after 4 months, and more reduction by the end of the study (baseline mean HR 77.8 ±4.8 bpm vs 71.3 ±5.2 bpm at 6 mo). 

Both SBP and DBP were reduced vs baseline at the 2-, 4-, and 6-month assessments. By the 6-month assessment, the reduction was highly significant for both variables (baseline mean SBP 131.4 ±10.2 vs 123.5 ± 9.9 at 6 mo; baseline mean DBP 85.6 ± 6.8 vs 79.6 ±7.3 at 6 mo).

Additionally, participants experienced a statistically significant weight loss at 6 months vs baseline (baseline mean weight 64.1 ± 10.7 kg vs. 62.2 ± 9.9 kg at 6 mo).

Investigators further analyzed the data by comparing measurements from participants <50 years to measurements from participants >50 years of age. Both age subgroups experienced reductions in HR, SBP, and DBP; however, the reductions were greater in <50 group. The different response between the two subgroups was significant for HR and weight, highly significant for DBP, but not statistically significant for SBP.

The investigators concluded that their results “justify the incorporation of yoga as part of our lifestyle in prevention of age-related cardiovascular complications.” They also noted that the difference in response of the <50 and >50 age subgroups  may indicate that beginning a yoga practice at an earlier age, before the onset of age-related cardiovascular changes, may be more beneficial. 

Summary by Louise Fecher

Article from Harvard Health Publications website. Published November 1, 2010. Accessed February 12, 2015.

This general article about yoga briefly reviewed the ways that yoga can potentially benefit cardiovascular health, including reducing high blood pressure, enhancing cardiac rehabilitation, and lowering cardiovascular risk factors. According to the Harvard Health Publications website, “Taking fewer but deeper breaths each minute temporarily lowers blood pressure and calms the sympathetic nervous system, which is responsible for generating stress hormones.”

“Taking fewer but deeper breaths each minute temporarily lowers blood pressure and calms the sympathetic nervous system, which is responsible for generating stress hormones.” -Harvard Health Publications

Carol Krucoff, a yoga therapist at Duke Integrative Medicine, was quoted in the article. She recommended that persons interested in starting yoga, particularly if over 30 years of age, should choose a class that offers “the full package”–poses, breathing, and meditation–over one that includes simply “yoga-flavored exercise.”

Summary by Louise Fecher

Research paper by Ramesh L Bijlani, Rama P Vempati, Raj K Yadav, et al. The Journal of Alternative and Complementary Medicine. 2005;11(2):267-274. doi:10.1089/acm.2005.11.267

In this short-term study, investigators at the Integral Health Clinic in New Delhi, India, examined the effects of an 8-day lifestyle modification program, based on the principles of yoga, on biological markers for cardiovascular disease and diabetes mellitus. At the end of the program, significant improvements were seen in key variables, leading investigators to conclude that  “a simple, inexpensive, essentially educational intervention can make an appreciable contribution to primary prevention as well as management.”

Data were collected from 98 subjects who attended a lifestyle intervention program between May 2001 and November 2002. The participants ranged in age from 20 to 74 years and included both males and females. The 8-day outpatient course was offered to groups of 6 to 8 patients at a time for 3 to 4 hours daily. The comprehensive program included: 

• Educational sessions about yoga, nutrition, stress management, and disease management
• Yoga practice sessions with asana, pranayama, meditation, and deep relaxation 
• Educational films and handouts
• A one-to-one session with a physician for individualized advice 

Meals were not provided, but participants were encouraged to adopt a predominately vegetarian diet that included primarily grains, leafy green vegetables, and fruit. 

…[S]ignificant improvements were seen in key variables, leading investigators to conclude that  “a simple, inexpensive, essentially educational intervention can make an appreciable contribution to primary prevention as well as management.”

Fasting blood samples were drawn on day 1 of the program to assess baseline values, then again on day 10 to assess the effects of the intervention.  (The program included a 2-day weekend break.) Complete fasting plasma glucose (FPG) data were collected for 77 of the 98 participants; other study data were complete for all 98 participants.

Data analysis revealed that FPG, serum total cholesterol, low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein (VLDL) cholesterol, total cholesterol/high-density lipoprotein (HDL) cholesterol ratio, and triglycerides were significantly lower post-intervention. HDL was significantly higher post-intervention. (These changes were more apparent in subjects with hyperglycemia or hypercholesterolemia.)

“Mental stress . . . has been shown to raise serum cholesterol, and mental relaxation through meditation and other relaxation techniques has been shown to lower serum cholesterol. Therefore, it is not surprising that the biochemical profile of the patients improved when attention was paid to physical activity, stress reduction, and diet,” the investigators wrote.

Because the study did not include a control group, the investigators could not assess all factors that could have contributed to the observed changes, such as the subjects’ belief in the efficacy of the intervention (ie, placebo effect), the psychological benefit of receiving group support, and the opportunity to spend time in a non-stressful environment. “There is need for further studies to examine the long-term compliance and impact of the intervention,” they concluded. 

Summary by Louise Fecher