According to the Centers for Disease Control and Prevention, body mass index (BMI) and hypertension, or high blood pressure, are related. BMI is a measure of the health of an individual's weight. Being overweight is associated with high blood pressure. Conversely, losing weight can help decrease blood pressure. Therefore, it is important to monitor both BMI and blood pressure.
About BMI
BMI accounts for body mass and stature. It is a better predictor of body fat than measurements of mass or stature alone. It is calculated using the following formula: BMI = body mass (kg) ÷ stature (m^2). For example, an individual who weighs 220 lb. (100 kg) and is 6 ft. tall (1.83 m) has a BMI of 29.9 (100 ÷ 1.83^2 = 29.9). BMI between 18.5 and 24.9 is classified as normal, between 25.0 and 29.9 is overweight, and 30.0 or higher is obese.
About Hypertension
The Centers for Disease Control and Prevention defines blood pressure as the force blood applies to the arterial walls as it circulates through the body. It is measured while the heart beats, called systolic pressure, and while it rests, called diastolic pressure. Measurements are read as systolic pressure over diastolic pressure (SBP/DBP). According to a report published by the United States Department of Health and Human Services, blood pressure measurements less than 120/80 are classified as normal, 120 to 139/80 to 89 is prehypertension, 140 to 159/90 to 99 is stage 1 hypertension, and 160/100 or greater is classified as stage 2 hypertension. The report indicates that hypertension increases the risk for cardiovascular disease.
How Are BMI and Hypertension Associated?
Since obesity is a risk factor for hypertension, and BMI is a predictor of obesity, BMI and hypertension are associated. When BMI is above normal, hypertension is also more likely. The report by the United States Department of Health and Human Services recommends overweight and obese individuals take steps to decrease their BMI to within the normal range.
Lowering BMI
Decreasing body fat is the most effective way to lower BMI. McArdle, Katch and Katch recommend creating a negative energy balance to lose weight by expending more calories than consuming on a daily basis. This can be done by exercising more, eating less or both. The negative energy balance should equal about 500 calories daily to lose approximately one pound per week.
Limitations
BMI does not always predict obesity accurately. For example, resistance training adds muscle mass that will increase BMI without increasing body fat. Therefore, if blood pressure is normal while BMI is above normal, taking steps to decrease BMI may not be necessary.
References
- Centers for Disease Control and Prevention: High Blood Pressure
- The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure; U.S. Department of Health and Human Services; December 2003
- "Sports and Exercise Nutrition (Third Edition)"; William D. McArdle, Frank I. Katch and Victor L. Katch; 2009
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