Your blood pressure is a good indication of the health of your cardiovascular system. When your blood pressure is high, your heart is working under stressful conditions. A high blood pressure, also called hypertension, is categorized as such when you have chronic readings of 140/90 mmHg or higher. Prehypertension, the precursor to high blood pressure, is considered to be chronic readings over 120/80 mmHg. Your body weight is one major influence on your blood pressure.
Body Mass Index
The body mass index is a way of predicting your percent body fat by taking into account your height versus your weight. Individuals with a body mass index of 19 to 24 are considered normal. According to "Exercise Physiology" by George A. Brooks, Thomas D. Fahey, Kenneth M. Baldwin, men with a BMI of 25 to 30 and women with a BMI of 27 to 30 are considered moderately obese. Those with a BMI between 30 to 40 are categorized as massively obese and any person with a BMI over 40 is morbidly obese.
Obesity and Blood Pressure
Being obese puts you at an increased risk for developing hypertension. A larger person means there is more tissue to deliver blood to. The resistance surrounding the heart is greater when there is a larger amount of fat. In addition, venous return diminishes when there is less lean body mass to help the blood fight gravity and return back to the heart.
BMI and Blood Pressure
Your body mass index is directly related to your blood pressure. According to a study published in a 1994 issue of the "Journal of Hypertension" by Daniel W. Jones and colleagues, it does not matter what your weight is, it affects your blood pressure. This study found that with every increase on the BMI table, blood pressure increases approximately the same. Overweight to obese subjects experienced a 1 mmHg increase in diastolic pressure for every increase in body mass while normal BMI individuals experienced an increase in 0.89 mmHg diastolic pressure.
Problems with Body Mass Index
There is one major problem with the BMI scale; it cannot be used universally for all individuals. For example, if you are a body builder or serious weight trainer, the table does not take into account your lean body mass. You cannot tell the BMI table that most of your weight is from muscle, so you may be categorized as overweight or obese. You might try other methods, such as the skin fold test, to approximate your percent body fat.
Reducing Blood Pressure and Weight
Reducing your body fat is beneficial to controlling and preventing high blood pressure. According to a study published in "Obesity Research" in 2000 by I.L. Mertens, just a 5 to 10 percent weight loss can improve high blood pressure.