How does hypertension develop? How does obesity aggravate it?
What will be an ideal response?
The underlying causes of most cases of hypertension are not fully understood, but much is known about the physiological factors that affect blood pressure. Blood pressure arises from contractions in the heart muscle that pump blood away from the heart (cardiac output) and the resistance blood encounters in the arterioles (peripheral resistance). When either cardiac output or peripheral resistance increases, blood pressure rises. Cardiac output is raised when heart rate or blood volume increases; peripheral resistance is affected mostly by the diameters of the arterioles. Blood pressure is therefore influenced by the nervous system, which regulates heart muscle contractions and the arteriole’s diameters, and hormonal signals, which may cause fluid retention or blood vessel constriction. The kidneys play a key role in regulating blood pressure by controlling the secretion of the hormones involved in vasoconstriction and retention of sodium and water.
Most people with hypertension—an estimated 70 percent—are overweight or obese. Obesity is recognized as a major cause of high blood pressure, and the combination of obesity and hypertension greatly increases the risk for CVD. Obesity raises blood pressure by altering kidney function, increasing blood volume, and promoting blood vessel damage through insulin resistance.
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