Obesity is a growing health problem worldwide. It is associated with an increased cardiovascular risk on the one hand of obesity itself and on the other hand of associated medical conditions (hypertension, diabetes, insulin resistance, and sleep apnoea syndrome). Obesity has an important role in atherosclerosis and coronary artery disease. Obesity leads to structural and functional changes of the heart, which causes heart failure. Obesity is closely related to coronary atherosclerosis.

As body weight increases, the volume of blood also increases. The increased blood volume forces an abnormally high output of blood to be pumped from the heart even at rest. This makes the heart work harder. The heart chambers stretch and expand. The added workload thickens the heart muscle of the lower left chamber (left ventricle). The thickening effects both squeezing (contraction) and relaxation of the heart. Over time, the heart may not be able to keep up with the load. Congestive heart failure with shortness of breath or fluid buildup in the lungs may be the result.
Obese people often have high blood pressure. High blood pressure adds to the work of the heart. The heart muscle gets even thicker because of the increased pressure. Normal heart contraction and relaxation are affected, and the heart can no longer pump normally. High blood pressure and abnormal heart function may be improved by losing weight, but drug treatment is often needed.
Obesity also increases the risk of developing diabetes. Diabetes increases the risk of developing heart disease.

Many obese people notice shortness of breath when they lie down to sleep because having a large abdomen can interfere with the function of diaphragm. Some very obese people also develop an obstruction of the airway to the lungs when they sleep. The effect of gravity on the thickened tissues and muscles of the throat and neck may serve to block the passage of air to the lungs. This interrupts breathing temporarily, a condition called apnoea. The periods of apnoea reduce the amount of oxygen in the blood. The reduced blood oxygen due to apnoea can affect the heart’s rhythm and may be responsible for some cases of sudden death during sleep.

Low blood oxygen may also cause an increase in blood pressure in the lungs. Persistent increase in lung blood pressure eventually puts a strain on the right ventricle of the heart. The right ventricle, which pumps blood through the lungs, cannot keep up with the demand. Symptoms of breathlessness or fluid buildup in the body may result.
Obesity can change your cholesterol levels. Cholesterol is the fat which is responsible for the development of coronary heart disease or blockages in the arteries of the heart. It is present in very small quantity in the blood. The total quantity of cholesterol in blood is about 7.5 grams. The total body storage of cholesterol is very low. Cholesterol never leads to obesity. It is present only in animal products. In our body cholesterol is useful for many functions especially the cells wall formation. It also leads to absorption of fatty foods in the body. It is the composition of bile acids. So cholesterol is important but not very important and is not responsible for fatty process of obesity.