As defined by Medline Plus, blood pressure is "a measurement of the force applied to the walls of the arteries as the heart pumps blood through the body." The amount of force and volume of blood, as well as the size and flexibility of the arteries determines your blood pressure. The amount of muscle you have may also play a role in your blood pressure.
When you get your blood pressure tested, there are two numbers, a top number and bottom. The top number is a systolic measurement, which is the pressure in your arteries when your heart contracts. The bottom number as a diastolic measurement, which is the pressure in your arteries between heartbeats.
Your blood pressure constantly changes, but at a state of rest, you should typically have a systolic number less than or close to 120. Your diastolic number should be less than or close to 80. Your doctor usually pays more attention to your systolic reading, because it can be a major risk factor for people older than 50, the American Heart Association states.
Blood Pressure Regulation
When your stress level goes up, so does your blood pressure. But once your stress level returns to normal, your blood pressure does the same. According to a 2004 article published in "Science Daily," researchers at the Medical College of Georgia discovered that people with more muscle regulate blood pressure better in high-stress situations than people with a higher amount of fat. Leaner people's blood pressure returns to normal quicker than fatter people. (See reference 3)
High Blood Pressure Link
Previous studies and the study done by MCG researchers found a link between lean body mass and high blood pressure. In other words, people with leaner body masses have higher blood pressures when exercising. However, this isn't necessarily a bad thing, according to Dr. Gregory Harshfield, an author of the MCG study, because your blood pressure should elevate during periods of exercise. (See reference 3)
Researchers in the MCG study found that people with more fat had more difficulty excreting sodium, which is the body's way of returning to normal blood pressure levels after stressful situations. Researchers found that people with leaner bodies were better able to return to normal blood pressure through excretion of sodium than people with more fat.