Hypertension, or high blood pressure, has long been associated with obesity. While obesity may contribute to several related conditions which cause hypertension, other causes may play a part. Diet and lifestyle choices which may contribute to obesity may also worsen your blood pressure. Genetics can also add to the negative effects of obesity.
Obesity and Blood Vessel Health
As noted on Nature.com, an abundance of adipose, or fat, tissue contributes to insulin resistance. The resultant increase in insulin production has several possible outcomes, including a thickening of the walls of your blood vessels. As they thicken, the walls of your vessels become more rigid. More rigid veins and arteries are less able to bend and flex to accommodate blood flow, and without your veins' ability to stretch, your blood pressure will increase. High circulating LDL and lower HDL ratios associated with obesity also contribute to plaque formation, which further narrows the blood vessels. Obesity also contributes to homocysteine, which can result in further inflammation.
Cardiac Hypertrophy and Cardiac Output
In a 2007 review published by the American Physiological Society, cardiac hypertrophy is noted as a common effect of obesity. When either a cardiac chamber or the entire heart become enlarged, cardiac output increases. Cardiac output may also increase due to heightened adrenalin levels. This increase in adrenaline caused your heart to work harder. This increased activity circulates your blood circulates more quickly and increases pressure as blood flows through the limited space within your thickened, hardened blood vessels.
Kidney Functions and Blood Volume
Obesity and related conditions, such as diabetes, can also affect your kidneys and cause them to retain salt and water. When your kidneys retain water, your body's blood volume increases. There is a direct correlation between blood volume and blood pressure, which is detailed by the Santa Barbara City College Department of Biological Sciences. The increase in blood volume causes an increase in venous return of blood to the heart, resulting in an increase in stroke volume. Your blood pressure then rises in response to this increase in cardiac activity.
Effects of Salt and Sodium
In June 2010, researchers from the Medical College of Georgia documented the connections between excess fat and sodium retention. This causes increased sodium sensitivity in some cases and, because obesity is often linked to unhealthy dietary habits, your sensitivity to salt may be further aggravated by high salt content in your food. An excess of sodium can increase rigidity in the peripheral arteries. Your blood pressure is affected by this heightened rigidity. Hardening of the blood vessel walls due to other factors related to obesity can further compound this problem.
- Science Daily: Connection Elucidated Between Obesity, Salt Sensitivity and High Blood Pressure
- Biological Sciences Santa Barbara City College: Cardiac Output
- Physiological Reviews: Cardiac Remodeling in Obesity
- Nature: Mechanisms linking obesity to insulin resistance and type 2 diabetes
- ThisIsDiabetes.com: Diabetes and Circulatory Disease