Journal of Medical Sciences and Health

Introduction

Stress, lifestyle changes and dyslipidemia are modifiable risk factors. Behavioral methods are recommended by the national cholesterol education program as the first line of prevention and treatment for hypercholesterolemia and other risk factors.[3] In recent years, there has been significant uptake of meditation and related relaxation techniques, as a means of alleviating stress and maintaining good health. Raja yoga meditation is a behavioral intervention which is practiced in India and all over the world. It appears to be the easy, practicable method of meditation, which one can follow on the day to day basis.[4] Some studies done on Raja-yoga meditators have shown increased parasympathetic activity in meditators and improvement in the lipid profile of meditators than non-meditators.[5-7] However, we have not come across any study done on the lipid profile of Raja-yoga meditators in central India. Therefore, we planned this study to find out the effect of Raja-yoga meditation on the lipid profile and fasting blood sugar (FBS) level of healthy volunteers of central India who were practicing it for 5 and more years for at least 1 h daily.

Material and Methods

The objectives of the study were explained to the participants, and their written informed consent was obtained. Equal numbers of male and female participants were included in each group. Anthropometric parameters like height and weight were measured, and body mass index (BMI) was calculated. The participants were called at 8 am after an overnight fast. Under all strict aseptic precautions, about 5 ml fasting blood sample was taken from each participant of both the groups with the help of disposable syringe and needle by venepuncture. Blood was collected in a plain bulb for lipid profile and fluoride bulb for FBS level. All the laboratory determinants were carried out in the Biochemistry Department of our Institute. The blood sample from plain bulb was centrifuged to separate serum for estimation of lipid profile. Serum total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) were estimated by kits provided by Accurex Biomedical Pvt. Ltd; Thane, India.[8] Low-density lipoprotein cholesterol (LDL-C) and very LDL-C (VLDL-C) were measured using the indirect method - The Friedewald equation.[9] FBS level was quantitatively estimated in the laboratory of biochemistry with the help of semiauto analyzer Tranasia Erba chem - 5-plus.

Statistical methods The data were analyzed to obtain the arithmetic mean for age, height, weight, TC, TG, HDL-C, LDL-C, VLDL-C and FBS. Difference in the mean values was subjected to Student’s t-test. Significance level was set as P < 0.05: Significant, P < 0.01: Highly significant, P < 0.001: Very highly significant.

Results

Discussion

Almost any type of stress causes an immediate and marked increase in ACTH secretion by the anterior pituitary gland, followed within minutes by greatly increased adrenocortical secretion of cortisol. Cortisol promotes mobilization of fatty acids from adipose tissue. This increases the concentration of free fatty acids in the plasma. Cortisol also seems to have a direct effect to enhance the oxidation of fatty acids in the cell. The mechanism, by which cortisol promotes fatty acid mobilization, is not completely understood. However, part of the effect probably results from diminished transport of glucose into the fat cells. Alpha glycerophosphate derived from glucose is required for both deposition and maintenance of TG in these cells and in its absence fat cells begin to release fatty acids.[14] Kamei et al.[15] examined changes in brain waves and blood levels of serum cortisol during yoga exercise in seven yoga instructors and found that alpha power increased, and serum cortisol decreased. They stated that there was an inverse correlation between the alpha power and the cortisol levels in yogis. The decreased stress hormone level (cortisol) may support the biological mechanism of meditation in improving the lipid profile of meditators.

All nucleated cells synthesize cholesterol, but only hepatocytes can efficiently metabolize and excrete cholesterol from the body. The predominant route of cholesterol elimination is by excretion into the bile, either directly or after conversion to bile acids. Cholesterol in peripheral cells is transported from the plasma membranes of peripheral cells to the liver by an HDL-mediated process termed reverse cholesterol transport.[16] Thus, HDL plays an important role in lowering the cholesterol level in the blood and exerts its cardio-protective effect. The significantly increased HDL level in meditators than non-meditators in our study probably protect from the development of CVD.

Meditation via its action on the hypothalamus decreases the stress which causes a decrease in the secretion of corticotropin-releasing factor, ACTH and consequently the stress hormone cortisol.[17,18] Decreased cortisol causes decrease fat mobilization and decreased gluconeogenesis. This may be the probable mechanism in improving the lipid profile and FBS levels of meditators than non-meditators.

The lipid profile of both the groups in our study was in a normal reference range though the values of TG, TC and HDL-C were significantly less in meditators. Maintaining low cholesterol content is one of the important measures to protect against the development of atherosclerosis and its progression to serious vascular disease. Studies have shown that for each 1 mg/dl decrease in LDL-C in the plasma, there is about 2% decrease in mortality from atherosclerotic heart disease.[19]

Cortisol released in response to stress potentiates glucose stimulus for insulin secretion. Prolonged secretion of cortisol in large quantities can occasionally lead to exhaustion of beta cells of islets of Langerhans and thereby increase the risk of developing diabetes mellitus.[20] Considering the possibility of Raja yoga meditation in alleviating the stress levels and thereby the blood glucose level in response to stress by above mechanism, we estimated fasting blood glucose levels and compared in both the groups. All the study participants showed the FBS values in the normal range (80-90 mg/dl).[20]

But there was no significant difference in the mean value of FBS level of meditators and non-meditators. Similar findings were also obtained by Sivasankaran et al.[10] Another study reported improvement in the FBS level which was statistically significant to the extent P < 0.001, but this study involved hath yoga as an intervention and was done in Type 2 diabetic patients in the longitudinal set up.[21]

Our study shows that the lipid profile of meditators who were practicing Raja Yoga meditation for minimum 5 years for at least 1 h daily is better than the non-meditators. The significantly increased HDL level in meditators than non-meditators in our study can protect the individual from the development of CVD. Raja yoga meditation can be looked upon an effective means for minimizing the development of CVD and maintaining good health. However, there are few limitations to our study. The study was carried out on the small group to see the effect of Raja yoga in a cross-sectional way. The longitudinal study should be carried out which should periodically assess the parameters of lipid profile.