OBESITY AND CARDIOVASCULAR DISEASE
While weight gain and obesity adversely affect the heart and the entire cardiovascular system in many ways, I think it is important to point out a few of the ways doctors and researchers can actually measure that negative impact. One simple method is to measure the blood pressure in people of different weights, and in the same person over time as his or her weight changes. Such studies find that weight gain is associated with elevated blood pressure increasing the body weight by 22 pounds or more (10 kg) is associated with a 3 mm of Mercury higher systolic blood pressure and a 2.3 mm higher diastolic blood pressure. This is rather significant and increases the incidence of coronary heart disease and stroke.
By contrast, weight loss translates into reduced blood pressure and reduced risk. In more than half of individuals, decreasing even one 1 kg, or a mere 2.2 pounds of body weight reduced the systolic blood pressure 1-4 mm of Mercury and the diastolic 1-2 mm of Mercury according to several studies. While these are not huge numbers, they represent a tangible improvement in health and measurable reduction in risk of heart attack.
The ability of the heart muscle to squeeze and pump blood is also adversely affected by weight gain. A 2006 study in the Journal of the American College of Cardiology demonstrates that right ventricular function suffers as body mass index rises. This association remained present when the right ventricular function changes were adjusted for age, for diabetes and insulin usage and blood pressure. This cardiac function is measured using several techniques – images with ultrasound, images with nuclear isotope labeling, and with inserted catheters that use measuring instruments. In all of these measurement methods, heart performance suffers when body weight rises. This means less energy, less blood available to the tissues that need it most during exertion, and more chance of fatigue or loss of vital blood supply to organs thirsty for it, like the kidneys.