Literature Review
BODY MASS INDEX (BMI)
Being overweight or obese increases the risk of having high blood pressure and increases the risk of cardiovascular disease associated with hypertension. The definition of overweight and obese are based upon a calculation called Body Mass Index (BMI).
Body Mass Index (BMI) is a number calculated from a person's weight and height. BMI is a fairly reliable indicator of body fatness for most people. BMI does not measure body fat directly, but research has shown that BMI correlates to direct measures of body fat, such as underwater weighing and dual energy x-ray absorptiometry (DXA).
BMI is an inexpensive and easy-to-perform method when compared to skinfold thickness measurements (with calipers), underwater weighing, bioelectrical impedance, dual-energy x-ray absorptiometry (DXA), and isotope dilution where these methods are not always readily available, and they are either expensive or need highly trained personnel. Furthermore, many of these methods can be difficult to standardize across observers or machines, complicating comparisons across studies and time periods.
A person is said to be overweight if their BMI is greater than 25, while a person with a BMI greater than 30 is said to be obese. Obesity raises blood pressure and makes high blood pressure more difficult to control.
Formula:
The formula for BMI is weight (in kilograms) divided by height (in metres) squared.
Example: Weight = 68 kg, Height = 1.65 m
Calculation: BMI = 68 ÷ (1.65)2 = 24.98
For adults 20 years old and older, BMI is interpreted using standard weight status categories that are the same for all ages and for both men and women. The standard weight status categories associated with BMI ranges for adults are shown in the following table.
BLOOD PRESSURE
Blood pressure is the pressure of the blood against the walls of the arteries. To determine one’s blood pressure, doctor measures the maximum pressure (systolic) and the lowest pressure (diastolic) made by the beating of the heart.
The systolic pressure is the maximum pressure in an artery at the moment when the heart is beating and pumping blood through the body. The diastolic pressure is the lowest pressure in an artery in the moments between beats when the heart is resting.
The systolic pressure is always stated first. For example: 120/80 (120 over 80); systolic = 120, diastolic = 80.
Both the systolic and diastolic pressure measurements are important - if either one is raised, it means you have high blood pressure (hypertension).
The blood pressure in our body is always changing and it is part of the human physiology. It is very rare that someone's blood pressure is always the same because we are always active and we are always doing different things like eating, sitting, standing, walking, breathing, moving around and doing so many other things throughout a day.
Every time that we do something different, our blood pressure changes and it react to the different positions that we are in. It is important that doctors and other professionals have the set rate for each person that relates to blood pressure and what it should be, because it is just impossible for anyone to take his or her blood pressure all the time throughout the day.
This is why mean arterial pressure is important. Mean arterial pressure is a term used in medicine to describe a notional average blood pressure in an individual. It is defined as the average arterial pressure during a single cardiac cycle. Therefore, MAP is a useful medical measurement that indicates both overall health and risk for developing various cardiovascular diseases such as hypertension.
MAP is calculated based on the formula as shown below:
DBP: Diastolic Blood Pressure
Normal values of MAP vary widely but usually range between 77-97 mmHg.
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