Prof. J.P.N. Mishra
Quantitative evaluation of total cholesterol, triglyceride and differential cholesterol have shown a specific trend of change. Total cholesterol, triglyceride, low density lipoprotein (LDL) and very low density lipoprotein (VLDL) were found to be on lower side that too with a statistical significance, whereas high density lipoprotein (HDL) was reported to be increased significantly in the experimental group of subjects practicing Preksha Meditation practice module.
Prashad at el (2006) have also reported similar findings following the practice of pranayama and yogic exercise in normal healthy volunteers. They also found significant reduction in the level of serum triglyceride, free fatty acids & very low density lipoprotein cholesterol at the end of stage one, significantly increased high density lipoprotein cholesterol at the end of state 1 & 2, while there were no change in low density lipoprotein cholesterol level at either of the stages. A comprehensive life style education program based on yoga reduces risk factors for cardiovascular disease and Diabetes Mellitus in terms of significantly reduced fasting plasma glucose, serum total cholesterol, low density lipoprotein cholesterol, very low density lipoprotein cholesterol and the ratio of total cholesterol to high density lipoprotein cholesterol. However at the same time total triglyceride were at significantly lower side and high density lipoprotein cholesterol at significantly higher side. The changes were more marked in the subjects of hyperglycemia and hypercholesterolemia. On the basis of these findings it was then concluded that life style modification and stress management education program leads to favorable metabolic effects even within a period of two weeks (Bijlani at el 2005). Practice of Raja yoga meditation (short & long term duration) brings in significant reduction in total serum cholesterol and increase in high density lipoprotein cholesterol (Vyas et al, 2002).
While investigating interrelationship of obesity index and lipid profile following yogic life style Kurhade at el (2001) have observed elevation in high density lipoprotein level and lowering of low density lipoprotein and very low density lipoprotein cholesterol. The effect of yogic life style on lipid status was studied in angina patients & normal subjects with risk factors of coronary artery diseases byMahajan at el (1999). The subjects practicing yoga showed a regular decrease in all lipid parameters except high density lipoprotein cholesterol. The effect started from fourth weeks and lasted for forteen weeks. The authors, thus, concluded that effect of yogic life style on some of modifiable risk factors would probably explain the preventive and therapeutic benefit observed.
Bhaskaracharyula at el (1986) have stated that two weeks of practicing selected yogasanas have yielded significant increase in serum high density lipoprotein and a trend of reduction in serum cholesterol, triglyceride, low.density lipoprotein, very low density lipoprotein. Mishra & Pandey (1996) have also reported a significant increase in high density lipoprotein level following practice of Preksha yoga for short duration. Specialized Kriya yoga training program undertaken by healthy adults of both sexes have brought in significant reduction in total serum cholesterol, low density lipoprotein cholesterol and low density lipoprotein to high density lipoprotein ratio (Schmidt, 1997)
Lamb (2004) has also reported improvement in biochemical profile in terms of increase in high density lipoprotein cholesterol and decrease in total cholesterol, low density lipoprotein and very low density lipoprotein cholesterol.
It has been stated that sustained exercise increases the oxygen demand of the muscles, and whether the demand is met depends primarily on the adequacy of cardiac output and proper function of respiratory system. After several weeks of training the healthy individual increases cardiac output and thereby increase the rate of oxygen delivery to the tissues (Tortora, 2006). Physical conditioning (asanas, pranayama, meditation and relaxation) also causes an interesting effect upon the systemic blood pressure. After a conditioning period the relaxed individual show a reduction in systolic pressure and this lower pressure itself helps reduced myocardial oxygen requirements. Additional benefits to be gained from physical conditioning are an increase in high density lipoprotein, a substance that seems to counter the impact of cholesterol in heart disease, a decrease in triglyceride levels and improved in lung functions.
Most of the body's cholesterol is endogenous (internally synthesized) rather than dietary and to some extent the body compensates for variations in dietary intake, high intake somewhat inhibits hepatic cholesterol synthesis. However, the liver synthesizes a certain amount of cholesterol regardless of intake, and severe restriction of dietary cholesterol does not necessarily result in proportionate drawn in blood cholesterol. Dietary fatty acids also strongly influence cholesterol levels.
Vigorous exercises also lowers blood cholesterol levels. The mechanism is somewhat round about: Exercise reduces the sensitivity of the right atrium of the heart to blood pressure, so the heart secretes less atrial natriuretic factor. Consequently, the kidneys excrete less sodium and water, and the blood volume rises. This dilutes the lipoproteins in the blood, and the adiposites compensate by producing more lipoprotein lipase (Saladin, 2004). Thus the adiposites consume more blood triglyceride. This shrink the very low density lipoprotein particles, which shed some of their cholesterol in the process, and high density lipoprotein pick up this free cholesterol for removal by the liver.
Blood cholesterol is not only important measure of healthy lipid concentrations, however a high low density lipoprotein concentration is a warning sign because, as we can see from the function of low density lipoprotein, it signifies a high rate of cholesterol deposition in the arteries (Saladin, 2004). A high proportion of high density lipoprotein, on the other hand, is beneficial because it indicates that cholesterol is being removed from the arteries and transported to the liver for disposal.
Hormones are the primary regulators of fat metabolism and some important hormones which are involved in this process are insulin, glucagon, epinephrine, norepinephrine, human growth hormone and thyroxin. Probably the most dramatic increase that occurs in fat metabolism is that observed during exercise. This results almost entirely from release of epinephrine & norepinephrine by the adrenal medullae as a result of sympathetic stimulation. These two hormones directly activate hormone sensitive triglyceride lipase that is present in abundance in the fat cells and this causes very rapid break down of triglyceride and mobilization of fatty acids (Guyton, 1991). Following our experimental intervention most probably the parasympathetic nervous system got activated, resulting in alteration not only in fat mobilizations but also increased ratio of high density lipoprotein to low density lipoprotein. However exact mechanism of action in this regard needs to be investigated.
